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<!-- DFIN New ActiveDisclosure (SM) XBRL Linkbase Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date :2022-05-10T16:00:29.4637+00:00 -->
<!-- Copyright (c) 2022 Donnelly Financial Solutions, Inc. All Rights Reserved. -->
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Common Stock, Value, Issued, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Common Stock, Value, Issued, Beginning Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Common Stock, Value, Issued, Ending Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressStateOrProvince_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, State or Province</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressStateOrProvince_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, State or Province</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Liabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Liabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandElevenPlanAndTwoThousandTwentyOnePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2011 Plan and 2021 Plan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandElevenPlanAndTwoThousandTwentyOnePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Two Thousand Eleven Plan And Two Thousand Twenty One Plan [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandElevenPlanAndTwoThousandTwentyOnePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Two Thousand Eleven Plan And Two Thousand Twenty One Plan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Risk-free interest rate</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandTwentyOneEmployeeStockPurchasePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Two Thousand Twenty One Employee Stock Purchase Plan [ Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandTwentyOneEmployeeStockPurchasePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Two thousand twenty one employee stock purchase plan.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandTwentyOneEmployeeStockPurchasePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2021 Employee Stock Purchase Plan</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ISOMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">I S O [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ISOMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">ISO</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ISOMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ISO</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Aggregate Future Minimum Lease Payments</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfStockDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Class of Stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfStockDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Class of Stock [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfStockByClassTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Stock by Class [Table Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfStockByClassTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reserved Common Stock for Future Issuances</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeniorSecuredTwentyTwentyTermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Senior Secured Twenty Twenty Term Loan [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeniorSecuredTwentyTwentyTermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Senior secured 2020 term loan.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeniorSecuredTwentyTwentyTermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Senior Secured 2020 Term Loan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RedeemableConvertiblePreferredStockIssuedAndOutstandingTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Redeemable Convertible Preferred Stock Issued and Outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RedeemableConvertiblePreferredStockIssuedAndOutstandingTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Redeemable Convertible Preferred Stock Issued And Outstanding [Table Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RedeemableConvertiblePreferredStockIssuedAndOutstandingTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Redeemable convertible preferred stock issued and outstanding.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted-average shares of common stock outstanding, basic and diluted</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Number of Shares Outstanding, Basic and Diluted</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Redeemable Convertible Preferred Stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Redeemable Convertible Preferred Stock [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfStockholdersEquityNoteWarrantsOrRightsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfStockholdersEquityNoteWarrantsOrRightsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Fair Value of Warrants Calculated Using Black-Scholes Model</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted average contractual term, vested and exercisable</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsReceivableNetCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accounts receivable, net</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsReceivableNetCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts Receivable, after Allowance for Credit Loss, Current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsReceivableNetCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Accounts Receivable, after Allowance for Credit Loss, Current, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GrossProfitAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Gross Profit [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GrossProfitAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Gross profit</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockAndWarrantsIssuedDuringPeriodValuePreferredStockAndWarrants_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Conversion of preferred stock warrants to common stock warrants upon the closing of the IPO</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockAndWarrantsIssuedDuringPeriodValuePreferredStockAndWarrants_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock and Warrants Issued During Period, Value, Preferred Stock and Warrants</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Recurring and Nonrecurring [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SignificantAccountingPoliciesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Significant Accounting Policies</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CityAreaCode_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">City Area Code</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CityAreaCode_lbl" xlink:role="http://www.xbrl.org/2003/role/label">City Area Code</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_IssuanceOfOptionsUnderStockPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Issuance of options under stock plan.</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_IssuanceOfOptionsUnderStockPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of Options under Plan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Weighted Average Valuation Assumptions Used to Estimate Fair Value of Employee Stock Options</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquityParOrStatedValuePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Redeemable convertible preferred stock, par value</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_PercentageOfVotingPowerRequiredToOwn_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of voting power required to own</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_PercentageOfVotingPowerRequiredToOwn_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percentage of Voting Power Required to Own</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BasisOfAccountingPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Basis of Presentation</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BasisOfAccountingPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Basis of Accounting, Policy [Policy Text Block]</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasicAndDilutedOtherDisclosuresAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Cash and cash equivalents at beginning of period</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Cash and cash equivalents at end of period</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RestrictedStockUnitsOutstandingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Restricted stock units outstanding.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RestrictedStockUnitsOutstandingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restricted Stock Units Outstanding [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RestrictedStockUnitsOutstandingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restricted stock units outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TrancheOneLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Tranche One Loans</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TrancheOneLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Tranche One Loans [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TrancheOneLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Tranche one loans.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AmortizationOfFinancingCostsAndDiscounts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accretion of debt discount and amortization of debt issuance costs</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AmortizationOfFinancingCostsAndDiscounts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Amortization of Debt Issuance Costs and Discounts</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AmortizationOfFinancingCostsAndDiscounts_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Amortization of Debt Issuance Costs and Discounts, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Conversion of preferred stock to common stock upon initial public offering</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common Stock issued on conversion of convertible preferred stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period, Value, Conversion of Convertible Securities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Statement [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesARedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Series A redeemable convertible preferred stock.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesARedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Series A Redeemable Convertible Preferred Stock [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesARedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Series A</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesARedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Series A Redeemable Convertible Preferred Stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net cash used in investing activities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Cash Provided by (Used in) Investing Activities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Disclosure [Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Redeemable convertible preferred stock:</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Temporary Equity [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued compensation</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Employee-related Liabilities, Current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Employee-related Liabilities, Current, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialLiabilitiesFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total liabilities measured at fair value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialLiabilitiesFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Liabilities Fair Value Disclosure</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialLiabilitiesFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Financial Liabilities Fair Value Disclosure, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Property and equipment, net</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property and equipment, net</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment, Net</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Property, Plant and Equipment, Net, Beginning Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Property, Plant and Equipment, Net, Ending Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares issued</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Shares, Issued</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Common Stock, Shares, Issued, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAdditionalGeneralDisclosuresAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease right-of-use assets</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Right-of-Use Asset</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ProceedsFromPaycheckProtectionProgramLoan_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from Paycheck Protection Program loan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ProceedsFromPaycheckProtectionProgramLoan_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds From Paycheck Protection Program Loan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ProceedsFromPaycheckProtectionProgramLoan_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Proceeds from Paycheck Protection Program loan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ProceedsFromPaycheckProtectionProgramLoan_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Proceeds from Paycheck Protection Program loan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_SecurityExchangeName_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Security Exchange Name</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_SecurityExchangeName_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Security Exchange Name</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_RangeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statistical Measurement</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_RangeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statistical Measurement [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2025</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Maturity, Year Three</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FurnitureAndFixturesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Furniture and Fixtures</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FurnitureAndFixturesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Furniture and Fixtures [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Line of Credit Facility, Unused Capacity, Commitment Fee Percentage</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Line of credit facility, unused capacity, commitment fee percentage</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total other noncurrent liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other noncurrent liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Liabilities, Noncurrent</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputPriceVolatilityMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Input, Price Volatility [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputPriceVolatilityMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Input Price Volatility</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Subsequent Event Type</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Event Type [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Line of Credit Facility, Maximum Borrowing Capacity</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maximum borrowing capacity</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentCovenantMinimumRevenue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Covenant Minimum Revenue</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentCovenantMinimumRevenue_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Debt instrument covenant minimum revenue.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentCovenantMinimumRevenue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt instrument covenant minimum revenue</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Disclosure [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentPeriodEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Period End Date</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentPeriodEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Period End Date</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ReplacementCostOfDevice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Replacement cost of device</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ReplacementCostOfDevice_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Replacement cost of Device</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementLocationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Statement Location</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementLocationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Statement Location [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsidiary or Equity Method Investee, Sale of Stock by Subsidiary or Equity Investee [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccruedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accrued Liabilities, Current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccruedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Accrued Liabilities, Current, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccruedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued expenses</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCreditFacilityLenderDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Line of Credit Facility, Lender [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WarrantsAndRightsOutstandingTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Term (in years)</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WarrantsAndRightsOutstandingTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Warrants and Rights Outstanding, Term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WarrantsAndRightsOutstandingTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Warrant term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WarrantMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Warrants</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WarrantMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Warrant [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_FundingOfTwoThousandNineteenTermLoanTranche3Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Funding of Two Thousand Nineteen Term Loan Tranche 3 [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_FundingOfTwoThousandNineteenTermLoanTranche3Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Funding of 2019 Term Loan Tranche 3</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_FundingOfTwoThousandNineteenTermLoanTranche3Member_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Funding of two thousand Nineteen term loan tranche 3.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares authorized</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Shares Authorized</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UseOfEstimates_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Use of Estimates</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UseOfEstimates_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Use of Estimates, Policy [Policy Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less: current portion of operating lease liability</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current portion of lease liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Liability, Current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_AccruedAccretionOnMaturityPayments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accrued Accretion On Maturity Payments</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_AccruedAccretionOnMaturityPayments_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Accrued accretion on maturity payments.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_AccruedAccretionOnMaturityPayments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued amount related accretion on maturity payments</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Supplemental disclosure of cash flow information</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Supplemental Cash Flow Information [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementClassOfStockAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Class of Stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementClassOfStockAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Class of Stock [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Adjustments to reconcile net loss to net cash used in operating activities:</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandAndTwentyOnePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2021 Plan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandAndTwentyOnePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Two Thousand And Twenty One Plan [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandAndTwentyOnePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Two thousand and twenty one plan.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Redeemable convertible preferred stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCreditFacilityCommitmentFeeAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Line of Credit Facility, Commitment Fee Amount</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCreditFacilityCommitmentFeeAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Line of credit facility commitment fee amount</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2024</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">2024</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Maturity, Year Two</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Long-term Debt Instruments [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Expense, Debt</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest Expense, Debt, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest expense, debt</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandAndElevenPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Two Thousand And Eleven Plan [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandAndElevenPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2011 Plan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandAndElevenPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Two thousand and Eleven plan.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_VestingAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Vesting [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_FundingOfTranche1AndTranche2UnderTwoThousandNineteenTermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Funding of Tranche 1 and Tranche 2 under Two Thousand Nineteen Term Loan [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_FundingOfTranche1AndTranche2UnderTwoThousandNineteenTermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Funding of Tranche 1 and Tranche 2 under 2019 Term Loan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_FundingOfTranche1AndTranche2UnderTwoThousandNineteenTermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Funding of tranche 1 and tranche 2 under two thousand Nineteen term loan.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestPaidNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash paid for interest</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestPaidNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Paid, Excluding Capitalized Interest, Operating Activities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PostemploymentBenefitsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Postemployment Benefits [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressAddressLine2_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, Address Line Two</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressAddressLine2_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, Address Line Two</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current Fiscal Year End Date</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Current Fiscal Year End Date</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Organization consolidation and presentation of financial statements disclosure.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net change in cash and cash equivalents</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Term loan.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Term Loan [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Term Loan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segment Information</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting Disclosure [Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentFrequencyOfPeriodicPayment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Frequency of Periodic Payment</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentFrequencyOfPeriodicPayment_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt instrument, frequency of periodic payment</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Assets</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Assets [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_AccruedAndOtherCurrentLiabilitiesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Accrued and Other Current Liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_AccruedAndOtherCurrentLiabilitiesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accrued And Other Current Liabilities [Table Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_AccruedAndOtherCurrentLiabilitiesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Accrued and other current liabilities.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Conversion of preferred stock to common stock upon initial public offering, Shares</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Conversion of redeemable convertible preferred stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period, Shares, Conversion of Convertible Securities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityNoteStockSplit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stockholders' Equity Note, Stock Split</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityNoteStockSplit_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Stock split, description</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityNoteStockSplit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock split</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2023</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, Year One</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsPayableCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Accounts Payable, Current, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsPayableCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accounts payable</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsPayableCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts Payable, Current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument, Name</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Name [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrentStatementOfFinancialPositionExtensibleList_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, par value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Par or Stated Value Per Share</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Shares, Outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning Balance, shares</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending Balance, shares</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional paid-in-capital</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Additional Paid in Capital, Common Stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Additional Paid in Capital, Common Stock, Beginning Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Additional Paid in Capital, Common Stock, Ending Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TrancheThreeLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Tranche Three Loans</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TrancheThreeLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Tranche Three Loans [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TrancheThreeLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Tranche three loans.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Loss before income taxes</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss before income tax</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentType_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Type</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentType_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Type</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_VestingDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Vesting [Domain]</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Preferred Stock, Value, Issued, Ending Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Preferred Stock, Value, Issued, Beginning Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Preferred Stock, Value, Issued, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Operating lease liabilities - noncurrent</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Noncurrent portion of lease liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Liability, Noncurrent</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_OptionsGrantedToNewHiresMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Options Granted To New Hires [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_OptionsGrantedToNewHiresMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Options granted to new hires.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_OptionsGrantedToNewHiresMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Options Granted to New Hires</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts Payable and Other Accrued Liabilities, Current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued and other current liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total accrued and other current liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total current assets</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Assets, Current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForDoubtfulAccounts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Provision for doubtful accounts receivable</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForDoubtfulAccounts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts Receivable, Credit Loss Expense (Reversal)</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_OtherNonCurrentLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other noncurrent liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_OtherNonCurrentLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Non Current Liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_OtherNonCurrentLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other non current liabilities.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeStockOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of common stock under employee stock purchase plan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeStockOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Options to Purchase Common Stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeStockOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Payment Arrangement, Option [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongtermDebtTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-term Debt, Type [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted Average Remaining Contractual Term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Provision for income taxes</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Expense (Benefit)</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Income Tax Expense (Benefit), Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Supplemental noncash disclosure</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RedeemableConvertiblePreferredStockIssuanceCostValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Series F redeemable convertible preferred stock issuance cost</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RedeemableConvertiblePreferredStockIssuanceCostValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Redeemable Convertible Preferred Stock Issuance Cost Value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RedeemableConvertiblePreferredStockIssuanceCostValue_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">redeemable convertible preferred stock issuance cost value.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForRepurchaseOfRedeemableConvertiblePreferredStock_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Series F issuance costs</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForRepurchaseOfRedeemableConvertiblePreferredStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments for Repurchase of Redeemable Convertible Preferred Stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasicAndDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net loss per share attributable to common stockholders, basic and diluted</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasicAndDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share, Basic and Diluted</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasicAndDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Earnings Per Share, Basic and Diluted, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AreaOfLand_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease office space</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AreaOfLand_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Area of Land</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Antidilutive Securities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Antidilutive Securities [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Beginning Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Shares, Outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Common Stock, Shares, Outstanding, Beginning Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Common Stock, Shares, Outstanding, Ending Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Class of Warrant or Right</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Class of Warrant or Right [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Segment Reporting Information</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Segment Reporting Information, by Segment [Table Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PlanNameAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Plan Name</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PlanNameAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Plan Name [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt instrument, term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less: Accumulated depreciation</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Beginning Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Ending Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Forfeited/cancelled</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shares Available for Grant, Options forfeited/cancelled</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Line of Credit Facility, Current Borrowing Capacity</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Line of credit facility, current borrowing capacity</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockIssuedOnConversionOfConvertiblePreferredStock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common Stock issued on conversion of convertible preferred stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockIssuedOnConversionOfConvertiblePreferredStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Issued On Conversion Of Convertible Preferred Stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockIssuedOnConversionOfConvertiblePreferredStock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Common Stock issued on conversion of convertible preferred stock.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingExpenses_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating expense</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingExpenses_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Operating expense</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingExpenses_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total operating expenses</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingExpenses_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Expenses</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IPOMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">IPO [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IPOMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">IPO</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Inventory, Net, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Inventory, net</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Inventory, Net</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Balances as of June 30, 2021</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Weighted-Average Exercise Price</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Weighted-Average Exercise Price</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash flows from operating activities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Cash Provided by (Used in) Operating Activities [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_WarrantsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Warrants Fair Value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_WarrantsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Warrants fair value.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_WarrantsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Warrants fair value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ExerciseOfCommonStockWarrantsShares_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Exercise of common stock warrants, shares</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ExerciseOfCommonStockWarrantsShares_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Exercise of Common Stock Warrants, Shares</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ExerciseOfCommonStockWarrantsShares_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Exercise of common stock warrants shares.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Class of Warrant or Right, Exercise Price of Warrants or Rights</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Class of warrant exercise price</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ConversionAndReclassificationOfPreferredStockWarrantsToCommonStockWarrantsUponInitialPublicOffering_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Conversion of reclassification of preferred stock warrants to common stock warrants upon initial public offering</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ConversionAndReclassificationOfPreferredStockWarrantsToCommonStockWarrantsUponInitialPublicOffering_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Conversion and Reclassification of Preferred Stock Warrants to Common Stock Warrants Upon Initial Public Offering</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ConversionAndReclassificationOfPreferredStockWarrantsToCommonStockWarrantsUponInitialPublicOffering_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Conversion and reclassification of preferred stock warrants to common stock warrants upon initial public offering.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2024</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net loss attributable to common stockholders</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net loss</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net loss and comprehensive loss</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Net loss</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RevolvingCreditFacilityTwoThousandTwentyMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Revolving Credit Facility Two Thousand Twenty [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RevolvingCreditFacilityTwoThousandTwentyMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Revolving credit facility 2020.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RevolvingCreditFacilityTwoThousandTwentyMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revolving 2020</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lease, borrowing rate</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Weighted Average Discount Rate, Percent</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ResearchAndDevelopmentExpenseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Research and Development Expenses</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ResearchAndDevelopmentExpenseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Research and Development Expense [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalPeriodFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Fiscal Period Focus</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalPeriodFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Fiscal Period Focus</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock issuance costs</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Temporary Equity, Stock Issued During Period, Value, New Issues</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Issuance of Series E convertible preferred stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConvertiblePreferredStockNonredeemableOrRedeemableIssuerOptionValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Convertible Preferred Stock, Nonredeemable or Redeemable, Issuer Option, Value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConvertiblePreferredStockNonredeemableOrRedeemableIssuerOptionValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Redeemable convertible preferred stock outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_AccountingForPayrollProtectionProgramPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accounting for Payroll Protection Program</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_AccountingForPayrollProtectionProgramPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounting For Payroll Protection Program [Policy Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_AccountingForPayrollProtectionProgramPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Accounting for payroll protection program.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountingPoliciesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounting Policies [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressAddressLine1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, Address Line One</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressAddressLine1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, Address Line One</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Aggregate intrinsic value of options exercised</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Number of Shares</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Number of Shares</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentPercentageOfPrepaymentPremiumYearOne_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Percentage of Prepayment Premium Year One</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentPercentageOfPrepaymentPremiumYearOne_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of prepayment premium year one</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentPercentageOfPrepaymentPremiumYearOne_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Debt instrument percentage of prepayment premium year one.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total current liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities, Current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareReconciliationAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Numerator:</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareReconciliationAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share Reconciliation [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProfitLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net loss</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProfitLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Income (Loss), Including Portion Attributable to Noncontrolling Interest</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProfitLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressPostalZipCode_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, Postal Zip Code</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressPostalZipCode_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, Postal Zip Code</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Fair Value Disclosure</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Debt Instrument, Fair Value Disclosure, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair value of outstanding debt</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Average Intrinsic Value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total future minimum lease payments</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquityCarryingAmountAttributableToParent_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Preferred stock par value of $0.001 per share; 10,000,000 shares authorized; no shares issued and outstanding as of March 31, 2022 and December 31, 2021, respectively</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquityCarryingAmountAttributableToParent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Convertible preferred stock par value of $0.001 per share; 10,000,000 shares authorized; no shares issued and outstanding as of March 31, 2022 and December 31, 2021, respectively</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquityCarryingAmountAttributableToParent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Carrying Value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquityCarryingAmountAttributableToParent_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquityCarryingAmountAttributableToParent_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquityCarryingAmountAttributableToParent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Temporary Equity, Carrying Amount, Attributable to Parent</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromIssuanceInitialPublicOffering_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from issuance of common stock upon initial public offering, net of underwriting discounts and commissions</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromIssuanceInitialPublicOffering_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Proceeds, net of underwriting discounts and commissions</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromIssuanceInitialPublicOffering_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Issuance Initial Public Offering</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CostOfGoodsAndServicesSoldAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cost of goods sold</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CostOfGoodsAndServicesSoldAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cost of Goods and Services Sold [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shares Available for Grant, Additional shares reserved</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TemporaryEquityIssuanceCost_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance Costs</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TemporaryEquityIssuanceCost_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Temporary Equity Issuance Cost</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TemporaryEquityIssuanceCost_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Temporary equity issuance cost.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net cash used in operating activities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Cash Provided by (Used in) Operating Activities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other noncurrent liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Other Noncurrent Liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementEquityComponentsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equity Components</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementEquityComponentsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity Components [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseCostTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Operating Lease Expense Recognized and Supplemental Cash Flow</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseCostTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lease, Cost [Table Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current assets:</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Assets, Current [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityRegistrantName_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Registrant Name</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityRegistrantName_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Registrant Name</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesFRedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Series F Redeemable Convertible Preferred Stock [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesFRedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Series F</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesFRedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Series F Redeemable Convertible Preferred Stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesFRedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Series F redeemable convertible preferred stock.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentInterestPaymentExtendedTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Debt instrument interest payment extended term.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentInterestPaymentExtendedTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Interest Payment Extended Term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentInterestPaymentExtendedTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt instrument interest payment extended term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentPercentageOfPrepaymentPremiumYearThree_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Debt instrument percentage of prepayment premium year three.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentPercentageOfPrepaymentPremiumYearThree_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Percentage of Prepayment Premium Year Three</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentPercentageOfPrepaymentPremiumYearThree_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of prepayment premium year three</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GainLossOnSaleOfPropertyPlantEquipment_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Loss on disposal of property and equipment</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GainLossOnSaleOfPropertyPlantEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Gain (Loss) on Disposition of Property Plant Equipment</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GainLossOnSaleOfPropertyPlantEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Gain (Loss) on Disposition of Property Plant Equipment, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantGrantedInPeriod_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Shares Available for Grant, Granted</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantGrantedInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Share-based compensation arrangement by share-based payment award, number of shares available for grant, granted in period.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantGrantedInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant, Granted in Period</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityNoteDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stockholders' Equity</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityNoteDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stockholders' Equity Note Disclosure [Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityInteractiveDataCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Interactive Data Current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityInteractiveDataCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Interactive Data Current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressCityOrTown_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, City or Town</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressCityOrTown_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, City or Town</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2022 (remainder)</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">2022 (remainder)</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Maturity, Remainder of Fiscal Year</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentInterestPaymentTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Debt instrument interest payment term.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentInterestPaymentTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Interest Payment Term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentInterestPaymentTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt instrument interest payment term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputExpectedTermMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Input, Expected Term [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputExpectedTermMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Input Expected Term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SupplementalBalanceSheetDisclosuresTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Balance Sheet Components</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SupplementalBalanceSheetDisclosuresTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Supplemental Balance Sheet Disclosures [Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Expected term (in years)</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_TradingSymbol_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Trading Symbol</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_TradingSymbol_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Trading Symbol</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash flows from investing activities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Cash Provided by (Used in) Investing Activities [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less: imputed interest</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, Undiscounted Excess Amount</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based Payment Arrangement, Restricted Stock Unit, Activity</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesFRedeemableConvertiblePreferredStockAndWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Series F redeemable convertible preferred stock and warrants.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesFRedeemableConvertiblePreferredStockAndWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Series F Redeemable Convertible Preferred Stock and Warrants [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesFRedeemableConvertiblePreferredStockAndWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Series F Redeemable Convertible Preferred Stock and Warrants</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesFRedeemableConvertiblePreferredStockAndWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Series F Redeemable Convertible Preferred Stock and Warrants</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialLiabilitiesFairValueDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Liabilities:</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialLiabilitiesFairValueDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Liabilities Fair Value Disclosure [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_LocalPhoneNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Local Phone Number</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_LocalPhoneNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Local Phone Number</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Number of Shares, Vested and expected to vest as of March 31, 2022</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total stockholders' equity (deficit)</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stockholders' Equity Attributable to Parent</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsOfDebtIssuanceCosts_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Debt issuance costs - third party</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsOfDebtIssuanceCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments of Debt Issuance Costs</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Subsequent Event Type</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Event Type [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeasePayments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash paid for operating leases</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeasePayments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Payments</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Preferred Stock, Shares Issued</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Preferred Stock, Shares Issued</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Preferred Stock, Shares Issued, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SeriesEPreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Series E</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SeriesEPreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Series E Preferred Stock [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_RangeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statistical Measurement</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_RangeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statistical Measurement [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntitySmallBusiness_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Small Business</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntitySmallBusiness_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Small Business</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ToolsDiesAndMoldsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Tools and Equipment</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ToolsDiesAndMoldsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Tools, Dies and Molds [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Preferred Stock, Shares Outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Preferred Stock, Shares Outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Preferred Stock, Shares Outstanding, Ending Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Preferred Stock, Shares Outstanding, Beginning Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Organization, Consolidation and Presentation of Financial Statements [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Hierarchy and NAV</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Hierarchy and NAV [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OverAllotmentOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Over-Allotment Option [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OverAllotmentOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Underwriters' Option</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditFacilityAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Facility [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditFacilityAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit Facility</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-term Debt, Excluding Current Maturities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term debt</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total accrued and other current liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Total accrued and other current liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_VariableRateAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Variable Rate</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_VariableRateAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Variable Rate [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_VariableRateDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Variable Rate</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_VariableRateDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Variable Rate [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TrancheTwoLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Tranche Two Loans</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TrancheTwoLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Tranche Two Loans [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TrancheTwoLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Tranche two loans.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAdjustmentOfWarrants_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Adjustment of Warrants</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAdjustmentOfWarrants_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Change in fair value of redeemable convertible preferred stock warrant</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConversionOfStockSharesIssued1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Conversion of Stock, Shares Issued</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConversionOfStockSharesIssued1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share of common stock issued upon warrant exercised</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromShortTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Short-term Debt</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromShortTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Proceeds from Short-term Debt, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromShortTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loan received</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedContributionPlanTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Defined Contribution Plan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedContributionPlanTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Contribution Plan [Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Class of Warrant or Right, Outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Warrant outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockWarrantsIssuedOnConversionOfPreferredStockWarrantsAndTheReclassificationOfTheWarrantLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock warrants issued on conversion of preferred stock warrants and the reclassification of the warrant liability</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockWarrantsIssuedOnConversionOfPreferredStockWarrantsAndTheReclassificationOfTheWarrantLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Warrants Issued on Conversion of Preferred Stock Warrants and the Reclassification of the Warrant Liability</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockWarrantsIssuedOnConversionOfPreferredStockWarrantsAndTheReclassificationOfTheWarrantLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Common stock warrants issued on conversion of preferred stock warrants and the reclassification of the warrant liability.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted-Average Exercise Price, Granted</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sale of Stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Sale of Stock [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquitySharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Redeemable convertible preferred stock, shares issued</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquitySharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Temporary Equity, Shares Issued</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquitySharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Shares Issued</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity [Abstract]</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ConversionAndReclassificationOfPreferredStockWarrantsToCommonStockWarrantsUponInitialPublicOfferingShares_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Conversion and Reclassification of Preferred Stock Warrants to Common Stock Warrants Upon Initial Public Offering, Shares</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ConversionAndReclassificationOfPreferredStockWarrantsToCommonStockWarrantsUponInitialPublicOfferingShares_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Conversion and Reclassification of Preferred Stock Warrants to Common Stock Warrants Upon Initial Public Offering, Shares</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PlanNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Plan Name</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PlanNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Plan Name [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfStockLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Class Of Stock [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfStockLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Class of Stock [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCreditFacilityAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lender Name [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2023</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">2023</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Maturity, Year One</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Depreciation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Depreciation</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Depreciation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Depreciation</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Depreciation_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Depreciation, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseTermOfContract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseTermOfContract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Term of Contract</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueNewIssues_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of common stock in connection with initial public offering, net of issuance costs</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueNewIssues_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period, Value, New Issues</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalOther_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred initial public offering cost recorded to additional paid in capital</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalOther_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Adjustments to Additional Paid in Capital, Other</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Liabilities Measured on Recurring Basis [Table Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Fair Value Measurement of Liabilities of Measured on Recurring Basis</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputExpectedDividendRateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Input, Expected Dividend Rate [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputExpectedDividendRateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Input Expected Dividend Rate</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_LineOfCreditFacilityCollateralFeesPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Line Of Credit Facility Collateral Fees Percentage</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_LineOfCreditFacilityCollateralFeesPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Line of credit facility collateral fees.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_LineOfCreditFacilityCollateralFeesPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Line of credit facility collateral fees</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Expense</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest Expense, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpense_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Interest expense</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentUnamortizedDiscount_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less: debt discount related to warrant liability and issuance costs</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentUnamortizedDiscount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Unamortized Discount</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentUnamortizedDiscount_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Debt Instrument, Unamortized Discount, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock-based compensation expense</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Payment Arrangement, Noncash Expense</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Share-based Payment Arrangement, Noncash Expense, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Prepaid expenses and other current assets</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Prepaid Expense and Other Assets, Current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Payment Arrangement, Option, Activity [Table Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Stock Option Activity</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-Lived Tangible Asset</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Lived Tangible Asset [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-term Debt, Gross</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Principal payments due</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingInformationLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting Information [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_NoncashOperatingLeaseCost_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Noncash operating lease expense</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_NoncashOperatingLeaseCost_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Noncash Operating Lease Cost</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_NoncashOperatingLeaseCost_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Noncash Operating Lease Cost</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredOfferingCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Deferred initial public offering cost recorded to additional paid in capital</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredOfferingCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total deferred costs</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredOfferingCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Offering Costs</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredOfferingCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred offering costs</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementInputsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Measurements</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementInputsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Measurement and Measurement Inputs, Recurring and Nonrecurring [Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Less: Current portion</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-term Debt, Current Maturities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Long-term Debt, Current Maturities, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AlternativeInvestmentMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Alternative investment, measurement input</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AlternativeInvestmentMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Alternative Investment, Measurement Input</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net cash provided by (used in) financing activities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Cash Provided by (Used in) Financing Activities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commitments and Contingencies Disclosure [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">New operating lease assets obtained in exchange for operating lease liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Right-of-Use Asset Obtained in Exchange for Operating Lease Liability</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredFinanceCostsNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Issuance Costs, Net</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredFinanceCostsNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Debt Issuance Costs, Net, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredFinanceCostsNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt issuance costs</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Assets_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total assets</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Assets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Assets</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel2Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Inputs, Level 2</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel2Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Inputs, Level 2 [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeBenefitsAndShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock based compensation</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeBenefitsAndShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Employee Benefits and Share-based Compensation</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred costs, current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts Receivable, Allowance for Credit Loss</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Accounts Receivable, Allowance for Credit Loss, Ending Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Accounts Receivable, Allowance for Credit Loss, Beginning Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of common stock upon exercise of stock options, shares</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Exercise of options under stock plan</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued compensation</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Employee Related Liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Increase (Decrease) in Employee Related Liabilities, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ShareBasedCompensationArrangementByShareBasedPaymentExercisePricePercentageGranted_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Exercise price percentage of an ISO granted</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ShareBasedCompensationArrangementByShareBasedPaymentExercisePricePercentageGranted_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share Based Compensation Arrangement By Share Based Payment Exercise Price Percentage Granted</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ShareBasedCompensationArrangementByShareBasedPaymentExercisePricePercentageGranted_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Share based compensation arrangement by share based payment exercise price percentage granted.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statement [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total liabilities, redeemable convertible preferred stock and stockholders' equity (deficit)</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentQuarterlyReport_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Quarterly Report</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Class of Warrant or Right</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesCRedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Series C Redeemable Convertible Preferred Stock [Member]</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesCRedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Series C redeemable convertible preferred stock.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfCashFlowsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Cash Flows [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockWarrantsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common Stock Warrants</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockWarrantsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Warrants [Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockWarrantsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Common stock warrants.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Additional Paid-in Capital [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional Paid-In Capital</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_Security12bTitle_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Title of 12(b) Security</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_Security12bTitle_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Title of 12(b) Security</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_LongTermDebtMaturityAfterYearThree_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Thereafter</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_LongTermDebtMaturityAfterYearThree_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Thereafter</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_LongTermDebtMaturityAfterYearThree_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Maturity, after Year Three</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_LongTermDebtMaturityAfterYearThree_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Amount of long-term debt payable, sinking fund requirement, and other securities issued that are redeemable by holder at fixed or determinable price and date, maturing after third fiscal year following current fiscal year.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel3Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Inputs, Level 3</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel3Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Inputs, Level 3 [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_MidCapFinancialServicesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Mid Cap Financial Services [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_MidCapFinancialServicesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Mid Cap Financial Services.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_MidCapFinancialServicesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Mid Cap Financial Services</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Award Type</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Award Type [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Vesting percentage</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_AlternativeInvestmentMeasurementInputPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Alternative Investment Measurement Input Period</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_AlternativeInvestmentMeasurementInputPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Period of input used to measure alternative investment.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_AlternativeInvestmentMeasurementInputPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Warrants expiration term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Hierarchy and NAV</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Hierarchy and NAV [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock option grant period</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentIncomeInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investment Income, Interest</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentIncomeInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest income</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Organization Consolidation And Presentation Of Financial Statements Disclosure [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Organization Consolidation And Presentation Of Financial Statements Disclosure [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Organization consolidation and presentation of financial statements disclosure.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Property and Equipment, Net</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment [Table Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantForfeitedInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shares Available for Grant, Forfeited/cancelled</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantForfeitedInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Share-based compensation arrangement by share-based payment award, number of shares available for grant, forfeited in period.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantForfeitedInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant, Forfeited in Period</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Inputs, Level 1</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Inputs, Level 1 [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Share of common stock purchased</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock-based compensation expense</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restricted Stock [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Weighted-Average Exercise Price, Vested and exercisable as of March 31, 2022</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Vested and exercisable as of June 30, 2021</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquityLiquidationPreference_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Temporary Equity, Liquidation Preference</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquityLiquidationPreference_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Liquidation Amount</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquityLiquidationPreference_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Convertible preferred stock, aggregate liquidation preference</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsidiarySaleOfStockLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsidiary, Sale of Stock [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Number of Shares, Granted</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of options under plan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Shares Available for Grant, Option granted</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCurrentReportingStatus_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Current Reporting Status</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCurrentReportingStatus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Current Reporting Status</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentPercentageOfPrepaymentPremiumYearTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Debt instrument percentage of prepayment premium year two.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentPercentageOfPrepaymentPremiumYearTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Percentage of Prepayment Premium Year Two</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentPercentageOfPrepaymentPremiumYearTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of prepayment premium year two</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Input Type</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Input Type [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted average, Grant</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Stock-Based Compensation Expense by Function</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2022</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComputerEquipmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Computer Equipment and Software</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComputerEquipmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Computer Equipment [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DeferredOfferingCostsPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Offering Costs</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DeferredOfferingCostsPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Offering Costs [Policy Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DeferredOfferingCostsPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Deferred offering costs.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpensesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Selling, General and Administrative Expenses</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpensesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Selling, General and Administrative Expenses [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongtermDebtTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-term Debt, Type [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCostsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred costs, current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCostsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Deferred Costs, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCostsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Costs, Current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementLocationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Statement Location</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementLocationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Statement Location [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_WarrantDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Redeemable Convertible Preferred Stock Warrants</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_WarrantDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Warrant Disclosure [Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_WarrantDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">The entire disclosure for warrants.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Changes in Level 3 Fair Value Instruments</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationAwardTrancheOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Payment Arrangement, Tranche One [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationAwardTrancheOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">At the End of One Year</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Class Of Warrant Or Right [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Class of Warrant or Right [Table]</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ExerciseOfCommonStockWarrants_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Exercise of Common Stock Warrants</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_ExerciseOfCommonStockWarrants_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Exercise of common stock warrants.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentCovenantMaximumRevenue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Covenant Maximum Revenue</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentCovenantMaximumRevenue_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Debt instrument covenant maximum revenue.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentCovenantMaximumRevenue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt instrument covenant maximum revenue</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Preferred stock, shares authorized</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Preferred Stock, Shares Authorized</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Weighted-Average Exercise Price, Expected to vest as of March 31, 2022</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Expected to vest as of June 30, 2021</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccruedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued and other current liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccruedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Accrued Liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccruedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Increase (Decrease) in Accrued Liabilities, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MinimumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Minimum [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MinimumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Minimum</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted average contractual term, vested and expected</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Frequency</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Frequency [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of common stock upon exercise of stock options</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period, Value, Stock Options Exercised</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Common stock warrants, net exercised</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDebtTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Long-term and Short-term Debt</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDebtTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Debt [Table Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Grant</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesBRedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Series B</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesBRedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Series B redeemable convertible preferred stock.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesBRedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Series B Redeemable Convertible Preferred Stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputRiskFreeInterestRateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Input, Risk Free Interest Rate [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputRiskFreeInterestRateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Input Risk Free Interest Rate</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Class of Warrant or Right, Number of Securities Called by Warrants or Rights</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Warrants issued to purchase shares of convertible preferred stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Warrants to purchase common stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TemporaryEquityOriginalIssuancePricePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Original Issuance Price</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TemporaryEquityOriginalIssuancePricePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Temporary Equity Original Issuance Price Per Share</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TemporaryEquityOriginalIssuancePricePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Temporary equity original issuance price per share.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentPaymentTerms_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Payment Terms</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentPaymentTerms_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt instrument payment terms</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash flows from financing activities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Cash Provided by (Used in) Financing Activities [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrecognized stock-based compensation of unvested options</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFilerCategory_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Filer Category</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFilerCategory_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Filer Category</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalYearFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Fiscal Year Focus</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalYearFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Fiscal Year Focus</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Number of Shares Vested and exercisable as of March 31, 2022</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Vested and exercisable as of June 30, 2021</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestPayableCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short term interest payable</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestPayableCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Payable, Current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConstructionInProgressMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Construction In Process</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConstructionInProgressMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Construction in Progress [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted-average grant-date fair values of options granted</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Retained Earnings (Accumulated Deficit), Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Retained Earnings (Accumulated Deficit), Beginning Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Retained Earnings (Accumulated Deficit), Ending Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated deficit</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Retained Earnings (Accumulated Deficit)</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel">Accumulated deficit</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_InterestPayableNonCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long term interest payable</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_InterestPayableNonCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Payable Non Current</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_InterestPayableNonCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest payable non current.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtDiscountAmortizedTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Debt discount amortized term.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtDiscountAmortizedTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Discount Amortized Term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtDiscountAmortizedTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt discount amortized term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityExTransitionPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Ex Transition Period</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityExTransitionPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Ex Transition Period</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseRemainingLeaseTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Remaining lease term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseRemainingLeaseTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Remaining Lease Term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueDisclosuresAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Disclosures [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MaximumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Maximum [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MaximumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maximum</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RedeemableConvertiblePreferredStockOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Redeemable convertible preferred stock outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RedeemableConvertiblePreferredStockOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">redeemable convertible preferred stock outstanding.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Central Index Key</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Central Index Key</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_IncentiveStockOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Incentive Stock Option [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_IncentiveStockOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Incentive stock option.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_IncentiveStockOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Incentive Stock Option</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Vested</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Input Type</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Input Type [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Expense</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease expense</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_IssuanceOfOptionsAndRestrictedStockUnitsUnderStockPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of options and restricted stock units under stock plan</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_IssuanceOfOptionsAndRestrictedStockUnitsUnderStockPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Issuance of options and restricted stock units under stock plan [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityTaxIdentificationNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Tax Identification Number</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityTaxIdentificationNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Tax Identification Number</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EquityComponentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity Component [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Preferred stock par value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Preferred Stock, Par or Stated Value Per Share</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Expected volatility</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandNineteenWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">2019 Warrants [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandNineteenWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2019 Warrants</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandNineteenWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Two Thousand Nineteen Warrants [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TwoThousandNineteenWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Two thousand Nineteen warrants.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segments</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segments [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted-average period expected to recognize</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TrancheOneAndTwoLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Tranche One And Two Loans [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TrancheOneAndTwoLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Tranche one and two loans.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TrancheOneAndTwoLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Tranche One and Two Loans</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Accounts receivable</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Accounts Receivable</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Events [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseholdImprovementsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Leasehold Improvements</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseholdImprovementsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Leasehold Improvements [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockOptionsIssuedAndOutstandingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Common stock options issued and outstanding.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockOptionsIssuedAndOutstandingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Options Issued And Outstanding [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockOptionsIssuedAndOutstandingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock options issued and outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statement [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Selling, general and administrative</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Selling, General and Administrative Expense</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Selling, General and Administrative Expense, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFileNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity File Number</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share Based Compensation Arrangement By Share Based Payment Award [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecuritiesNetOfAdjustments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Conversion of preferred stock warrants to common stock warrants upon the closing of the IPO</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecuritiesNetOfAdjustments_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Stock Issued During Period, Value, Conversion of Convertible Securities, Net of Adjustments, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecuritiesNetOfAdjustments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period, Value, Conversion of Convertible Securities, Net of Adjustments</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherNoncurrentAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Other Noncurrent Assets</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherNoncurrentAssets_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Other noncurrent assets</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Retained Earnings [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated Deficit</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesDRedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Series D redeemable convertible preferred stock.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesDRedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Series D Redeemable Convertible Preferred Stock [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesDRedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Series D</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesDRedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Series D Redeemable Convertible Preferred Stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revenue</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Revenue from Contract with Customer, Excluding Assessed Tax</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Revenue from Contract with Customer, Excluding Assessed Tax, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsOfStockIssuanceCosts_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Series E issuance costs</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsOfStockIssuanceCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Common stock issuance cost</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsOfStockIssuanceCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Estimated offering costs</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsOfStockIssuanceCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments of Stock Issuance Costs</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accounts payable</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Accounts Payable</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Increase (Decrease) in Accounts Payable, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseDiscountRate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease, discount rate</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseDiscountRate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Discount Rate</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current liabilities:</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities, Current [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockAvailableForFutureGrantMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Common stock available for future grant.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockAvailableForFutureGrantMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Available For Future Grant [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockAvailableForFutureGrantMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock available for future grant</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equity Incentive Plans</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Payment Arrangement [Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Subsequent Event</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Event [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commitments and Contingencies</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commitments and Contingencies Disclosure [Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Average Intrinsic Value, Vested and expected as of March 31, 2022</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableAggregateIntrinsicValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted average contractual term, vested and expected</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Present value of future minimum lease payments</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Present value of future minimum lease payments</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Liability</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesERedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Series E</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesERedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Series E redeemable convertible preferred stock.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesERedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Series E Redeemable Convertible Preferred Stock [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesERedeemableConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Series E Redeemable Convertible Preferred Stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common Stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment, Gross</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Property, Plant and Equipment, Gross, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Property, Plant and Equipment, Gross, Beginning Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Property, Plant and Equipment, Gross, Ending Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property and equipment, gross</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CoverAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cover [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditFacilityDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit Facility</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditFacilityDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Facility [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TotalBaseRentUnderLeaseAgreement_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total base rent under lease agreement</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TotalBaseRentUnderLeaseAgreement_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Total base rent under lease agreement</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TotalBaseRentUnderLeaseAgreement_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Total base rent under lease agreement.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value, Ending Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value, Beginning Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquitySharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Redeemable convertible preferred stock, shares outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquitySharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Temporary Equity, Shares Outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquitySharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Shares Outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquitySharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning Balance, shares</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TemporaryEquitySharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending Balance, shares</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfExtinguishmentOfDebtTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Repayment Schedule Relating to the Company's Debt</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfStockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Stockholders' Equity [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Property Plant And Equipment [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Balance - June 30, 2020</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending Balance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Payment Arrangement [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentPrincipalAndInterestPaymentTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Debt instrument principal and interest payment term.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentPrincipalAndInterestPaymentTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Principal and Interest Payment Term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentPrincipalAndInterestPaymentTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt instrument principal and interest payment term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueOfFinancialInstrumentsPolicy_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value of Financial Instruments</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueOfFinancialInstrumentsPolicy_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value of Financial Instruments, Policy [Policy Text Block]</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedStockUnitsRSUMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restricted Stock Units (RSUs) [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedStockUnitsRSUMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restricted Stock Units RSU</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-Lived Tangible Asset</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Lived Tangible Asset [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Segment Reporting Information, by Segment [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAccruedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other accrued liabilities</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentTransitionReport_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Transition Report</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentTransitionReport_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Transition Report</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted average, Vested</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Weighted Average Grant Date Fair Value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from exercise of common stock options</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Stock Options Exercised</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Defined contribution plan, maximum annual contributions per employee</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCreditFacilityCommitmentFeeDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Line of Credit Facility, Commitment Fee Description</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCreditFacilityCommitmentFeeDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Line of credit facility, commitment fee description</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RedeemableConvertiblePreferredStockWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Redeemable Convertible Preferred Stock Warrants</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RedeemableConvertiblePreferredStockWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Redeemable Convertible Preferred Stock Warrants [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RedeemableConvertiblePreferredStockWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Redeemable convertible preferred stock warrants liabilities.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ResearchAndDevelopmentExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Research and Development Expense</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ResearchAndDevelopmentExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Research and Development Expense, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ResearchAndDevelopmentExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Research and development</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CostOfGoodsAndServicesSold_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CostOfGoodsAndServicesSold_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cost of goods sold</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CostOfGoodsAndServicesSold_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cost of Goods and Services Sold</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CostOfGoodsAndServicesSold_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Cost of Goods and Services Sold, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_PaymentsOfStockIssuanceCostsRelatedToInitialPublicOffering_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Payments of costs related to initial public offering</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_PaymentsOfStockIssuanceCostsRelatedToInitialPublicOffering_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments Of Stock Issuance Costs Related To Initial Public Offering</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_PaymentsOfStockIssuanceCostsRelatedToInitialPublicOffering_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Payments of stock issuance costs related to initial public offering.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeniorSecuredTwoThousandNineteenTermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Senior Secured Two Thousand Nineteen Term Loan [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeniorSecuredTwoThousandNineteenTermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Senior secured 2019 term loan.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeniorSecuredTwoThousandNineteenTermLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Senior Secured 2019 Term Loan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DividendsCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dividends declared</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DividendsCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Dividends, Common Stock, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total stock-based compensation expense</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Payment Arrangement, Expense</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPeriodIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Change in fair value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPeriodIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease)</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPeriodIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Period Increase (Decrease), Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementBusinessSegmentsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segments</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementBusinessSegmentsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segments [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryWriteDown_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Provision for excess and obsolete inventories</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryWriteDown_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Inventory Write-down</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfFinancialPositionAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Financial Position [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dividend yield</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stockholders' equity (deficit):</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockVoteForEachShare_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of votes entitled per share of common stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockVoteForEachShare_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock Vote for Each Share</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_CommonStockVoteForEachShare_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Common stock, vote for each share.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NatureOfOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Company and Nature of Business</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Temporary equity, stock issued during period shares, new issues.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Temporary Equity Stock Issued During Period Shares New Issues</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of Series E convertible preferred stock, shares</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WarrantsAndRightsNoteDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Warrants and Rights Note Disclosure [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted-Average Exercise Price, Exercised/released</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_UnpaidInitialPublicOfferingCostsInAccountsPayableAndAccruedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Unpaid initial public offering costs in accounts payable and accrued liabilities.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_UnpaidInitialPublicOfferingCostsInAccountsPayableAndAccruedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Unpaid Initial Public Offering Costs In Accounts Payable And Accrued Liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_UnpaidInitialPublicOfferingCostsInAccountsPayableAndAccruedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unpaid initial public offering costs in accounts payable and accrued liabilities</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInInventories_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Inventory</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNoncurrentLiabilitiesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Other Noncurrent Liabilities</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Thereafter</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Maturity, Year Four</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Changes in operating assets and liabilities:</link:label>
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    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Common Stock, Shares Outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock reserved for future issuance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Capital Shares Reserved for Future Issuance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Common stock reserved for future issuance</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Frequency</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Frequency [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ReclassificationsOfTemporaryToPermanentEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reclassification of the related redeemable convertible preferred stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ReclassificationsOfTemporaryToPermanentEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Reclassifications of Temporary to Permanent Equity</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AwardTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Award Type</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AwardTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Award Type [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtLongtermAndShorttermCombinedAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total amounts outstanding</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtLongtermAndShorttermCombinedAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt, Long-term and Short-term, Combined Amount</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_UnderwritingDiscountsAndCommission_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Underwriting Discounts And Commission</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_UnderwritingDiscountsAndCommission_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Underwriting discounts and commission.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_UnderwritingDiscountsAndCommission_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Underwriting discounts and commissions</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityShellCompany_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Shell Company</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityShellCompany_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Shell Company</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockPricePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sale of stock, price per share</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockPricePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Sale of Stock, Price Per Share</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Liabilities, redeemable convertible preferred stock, and stockholders' equity (deficit)</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities and Equity [Abstract]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentInterestRateEffectivePercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Interest Rate, Effective Percentage</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentInterestRateEffectivePercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt instrument, effective interest rate</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityIncorporationStateCountryCode_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Incorporation, State or Country Code</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityIncorporationStateCountryCode_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Incorporation, State or Country Code</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesCRedeemableConvertiblePreferredStockAndWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Series C redeemable convertible preferred stock and warrants.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesCRedeemableConvertiblePreferredStockAndWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Series C Redeemable Convertible Preferred Stock and Warrants [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesCRedeemableConvertiblePreferredStockAndWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Series C Redeemable Convertible Preferred Stock and Warrants</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SeriesCRedeemableConvertiblePreferredStockAndWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Series C Redeemable Convertible Preferred Stock and Warrants</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net Loss per Share Attributable to Common Stockholders</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share [Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LondonInterbankOfferedRateLIBORMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">London Interbank Offered Rate (LIBOR) [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LondonInterbankOfferedRateLIBORMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">London Interbank Offered Rate (LIBOR)</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AmendmentFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amendment Flag</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AmendmentFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Amendment Flag</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfStockByClassTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Stock By Class [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfStockByClassTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Stock by Class [Table]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DryEyeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Dry Eye [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DryEyeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Dry eye.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DryEyeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dry Eye</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNonoperatingIncomeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other (expense) income, net</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNonoperatingIncomeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Nonoperating Income (Expense)</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNonoperatingIncomeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other Nonoperating Income (Expense), Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of shares sold</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Sale of Stock, Number of Shares Issued in Transaction</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Common stock issued</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash and cash equivalents</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Cash and cash equivalents at beginning of period</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Cash and cash equivalents at end of period</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash and Cash Equivalents, at Carrying Value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Cash and Cash Equivalents, at Carrying Value, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">New Accounting Pronouncements Not Yet Adopted</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">New Accounting Pronouncements, Policy [Policy Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityCurrentStatementOfFinancialPositionExtensibleList_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentFairValueAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Debt Instrument Fair Value, Amount</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentFairValueAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument Fair Value Amount</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_DebtInstrumentFairValueAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument, Fair Value Amount</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term Debt</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Long-term Debt, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-term Debt</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Term Loan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Total repayments</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel">Total repayments</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SurgicalGlaucomaMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Surgical Glaucoma [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SurgicalGlaucomaMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Surgical Glaucoma.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_SurgicalGlaucomaMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Surgical Glaucoma</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsRecurringMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Recurring</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsRecurringMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Recurring [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Events [Text Block]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Subsequent Events</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_OptionsGrantedMeritAwardsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Options Granted Merit Awards [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_OptionsGrantedMeritAwardsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Options Granted Merit Awards</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_OptionsGrantedMeritAwardsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Options granted merit awards.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_PaycheckProtectionProgramLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">PPP Loan</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_PaycheckProtectionProgramLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Paycheck Protection Program Loan [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_PaycheckProtectionProgramLoanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Paycheck Protection Program loan.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Antidilutive Securities, Name</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Antidilutive Securities, Name [Domain]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property Plant And Equipment [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment [Line Items]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssetsNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other Assets, Noncurrent, Total</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssetsNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other noncurrent assets</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssetsNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Assets, Noncurrent</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Average Intrinsic Value, Vested and exercisable as of March 31, 2022</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CostOfSalesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cost of Goods Sold</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CostOfSalesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cost of Sales [Member]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sale of Stock</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Sale of Stock [Axis]</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_FairValueOfWarrants_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Of Warrants</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_FairValueOfWarrants_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Fair value of warrants.</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_FairValueOfWarrants_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair value of warrants</link:label>
    <link:label xml:lang="en-US" xlink:type="resource" xlink:label="sght_RedeemableConvertiblePreferredStockTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Redeemable Convertible Preferred Stock</link:label>
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    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_lbl"/>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GrossProfit" xlink:to="us-gaap_GrossProfit_lbl"/>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="sght_RedeemablePreferredStockWarrantsLiabilitiesNonCurrent" xlink:to="sght_RedeemablePreferredStockWarrantsLiabilitiesNonCurrent_lbl"/>
    <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="sght_LeaseCommencementDate" xlink:to="sght_LeaseCommencementDate_lbl"/>
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