3.23.1 html 282 411 1 false 106 0 false 9 false false R1.htm 100000 - Document - Document and Entity Information Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DocumentDocumentAndEntityInformation Document and Entity Information Cover 1 false false R2.htm 100010 - Statement - CONSOLIDATED BALANCE SHEETS Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_StatementCONSOLIDATEDBALANCESHEETS CONSOLIDATED BALANCE SHEETS Statements 2 false false R3.htm 100030 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_StatementCONSOLIDATEDBALANCESHEETSParenthetical CONSOLIDATED BALANCE SHEETS (Parenthetical) Statements 3 false false R4.htm 100040 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_StatementCONSOLIDATEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVELOSS CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS Statements 4 false false R5.htm 100050 - Statement - CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED SHARES AND STOCKHOLDERS' EQUITY Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_StatementCONSOLIDATEDSTATEMENTSOFCONVERTIBLEPREFERREDSHARESANDSTOCKHOLDERSEQUITY CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED SHARES AND STOCKHOLDERS' EQUITY Statements 5 false false R6.htm 100060 - Statement - CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED SHARES AND STOCKHOLDERS' EQUITY (Parenthetical) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_StatementCONSOLIDATEDSTATEMENTSOFCONVERTIBLEPREFERREDSHARESANDSTOCKHOLDERSEQUITYParenthetical CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED SHARES AND STOCKHOLDERS' EQUITY (Parenthetical) Statements 6 false false R7.htm 100070 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_StatementCONSOLIDATEDSTATEMENTSOFCASHFLOWS CONSOLIDATED STATEMENTS OF CASH FLOWS Statements 7 false false R8.htm 100080 - Disclosure - Nature of the Business and Basis of Presentation Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureNatureOfBusinessAndBasisOfPresentation Nature of the Business and Basis of Presentation Notes 8 false false R9.htm 100090 - Disclosure - Summary of Significant Accounting Policies Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPolicies Summary of Significant Accounting Policies Notes 9 false false R10.htm 100100 - Disclosure - Fair Value Measurements and Marketable Securities Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsAndMarketableSecurities Fair Value Measurements and Marketable Securities Notes 10 false false R11.htm 100110 - Disclosure - Property and Equipment, Net Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosurePropertyAndEquipmentNet Property and Equipment, Net Notes 11 false false R12.htm 100120 - Disclosure - Leases Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureLeases Leases Notes 12 false false R13.htm 100130 - Disclosure - Accrued Expenses and Other Current Liabilities Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureAccruedExpensesAndOtherCurrentLiabilities Accrued Expenses and Other Current Liabilities Notes 13 false false R14.htm 100150 - Disclosure - Equity Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureEquity Equity Notes 14 false false R15.htm 100160 - Disclosure - Share-Based Compensation Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensation Share-Based Compensation Notes 15 false false R16.htm 100180 - Disclosure - Liability Related to the Sale of Future Royalties Sheet http://sperotherapeutics.com/20221231/taxonomy/role/DisclosureLiabilityRelatedToTheSaleOfFutureRoyalties1 Liability Related to the Sale of Future Royalties Notes 16 false false R17.htm 100190 - Disclosure - Restructuring Sheet http://sperotherapeutics.com/20221231/taxonomy/role/DisclosureRestructuring Restructuring Notes 17 false false R18.htm 100200 - Disclosure - Income Taxes Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxes Income Taxes Notes 18 false false R19.htm 100210 - Disclosure - Commitments and Contingencies Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureCommitmentsAndContingencies Commitments and Contingencies Notes 19 false false R20.htm 100220 - Disclosure - Government Contracts Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureGovernmentContracts Government Contracts Notes 20 false false R21.htm 100230 - Disclosure - License, Collaboration and Service Agreements Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureLicenseCollaborationAndServiceAgreements License, Collaboration and Service Agreements Notes 21 false false R22.htm 100250 - Disclosure - Net Loss per Share Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureNetLossPerShare Net Loss per Share Notes 22 false false R23.htm 100260 - Disclosure - Retirement Plan Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureRetirementPlan Retirement Plan Notes 23 false false R24.htm 100270 - Disclosure - Subsequent Events Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureSubsequentEvents Subsequent Events Notes 24 false false R25.htm 100280 - Disclosure - Summary of Significant Accounting Policies (Policies) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPoliciesPolicies Summary of Significant Accounting Policies (Policies) Policies http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPolicies 25 false false R26.htm 100290 - Disclosure - Summary of Significant Accounting Policies (Tables) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPoliciesTables Summary of Significant Accounting Policies (Tables) Tables http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPolicies 26 false false R27.htm 100300 - Disclosure - Fair Value Measurements and Marketable Securities (Tables) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsAndMarketableSecuritiesTables Fair Value Measurements and Marketable Securities (Tables) Tables http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsAndMarketableSecurities 27 false false R28.htm 100310 - Disclosure - Property and Equipment, Net (Tables) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosurePropertyAndEquipmentNetTables Property and Equipment, Net (Tables) Tables http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosurePropertyAndEquipmentNet 28 false false R29.htm 100320 - Disclosure - Leases (Tables) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureLeasesTables Leases (Tables) Tables http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureLeases 29 false false R30.htm 100330 - Disclosure - Accrued Expenses and Other Current Liabilities (Tables) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureAccruedExpensesAndOtherCurrentLiabilitiesTables Accrued Expenses and Other Current Liabilities (Tables) Tables http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureAccruedExpensesAndOtherCurrentLiabilities 30 false false R31.htm 100340 - Disclosure - Share-Based Compensation (Tables) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensationTables Share-Based Compensation (Tables) Tables http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensation 31 false false R32.htm 100350 - Disclosure - Liability Related to the Sale of Future Royalties (Tables) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/DisclosureLiabilityRelatedToTheSaleOfFutureRoyaltiesTables Liability Related to the Sale of Future Royalties (Tables) Tables http://sperotherapeutics.com/20221231/taxonomy/role/DisclosureLiabilityRelatedToTheSaleOfFutureRoyalties1 32 false false R33.htm 100360 - Disclosure - Restructuring (Tables) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/DisclosureRestructuringTables Restructuring (Tables) Tables http://sperotherapeutics.com/20221231/taxonomy/role/DisclosureRestructuring 33 false false R34.htm 100370 - Disclosure - Income Taxes (Tables) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesTables Income Taxes (Tables) Tables http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxes 34 false false R35.htm 100380 - Disclosure - License, Collaboration and Service Agreements (Tables) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureLicenseCollaborationAndServiceAgreementsTables License, Collaboration and Service Agreements (Tables) Tables http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureLicenseCollaborationAndServiceAgreements 35 false false R36.htm 100390 - Disclosure - Net Loss per Share (Tables) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureNetLossPerShareTables Net Loss per Share (Tables) Tables http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureNetLossPerShare 36 false false R37.htm 100400 - Disclosure - Nature of the Business and Basis of Presentation - Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureNatureOfBusinessAndBasisOfPresentationAdditionalInformationDetail Nature of the Business and Basis of Presentation - Additional Information (Detail) Details 37 false false R38.htm 100410 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetail Summary of Significant Accounting Policies - Additional Information (Detail) Details 38 false false R39.htm 100420 - Disclosure - Summary of Significant Accounting Policies - Estimated Useful Lives of Assets (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPoliciesEstimatedUsefulLivesOfAssetsDetail Summary of Significant Accounting Policies - Estimated Useful Lives of Assets (Detail) Details 39 false false R40.htm 100430 - Disclosure - Fair Value Measurements and Marketable Securities - Summary of Financial Assets and Liabilities Measured at Fair Value Recurring Basis (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsAndMarketableSecuritiesSummaryOfFinancialAssetsAndLiabilitiesMeasuredAtFairValueRecurringBasisDetail Fair Value Measurements and Marketable Securities - Summary of Financial Assets and Liabilities Measured at Fair Value Recurring Basis (Detail) Details 40 false false R41.htm 100440 - Disclosure - Fair Value Measurements and Marketable Securities - Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsAndMarketableSecuritiesAdditionalInformationDetail Fair Value Measurements and Marketable Securities - Additional Information (Detail) Details 41 false false R42.htm 100450 - Disclosure - Fair Value Measurements and Marketable Securities - Summary of Gross Unrealized Gains and Losses of Marketable Securities (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsAndMarketableSecuritiesSummaryOfGrossUnrealizedGainsAndLossesOfMarketableSecuritiesDetail Fair Value Measurements and Marketable Securities - Summary of Gross Unrealized Gains and Losses of Marketable Securities (Detail) Details 42 false false R43.htm 100460 - Disclosure - Property and Equipment, Net - Components of Property and Equipment, Net (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosurePropertyAndEquipmentNetComponentsOfPropertyAndEquipmentNetDetail Property and Equipment, Net - Components of Property and Equipment, Net (Detail) Details 43 false false R44.htm 100470 - Disclosure - Property and Equipment, Net - Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosurePropertyAndEquipmentNetAdditionalInformationDetail Property and Equipment, Net - Additional Information (Detail) Details 44 false false R45.htm 100480 - Disclosure - Leases - Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureLeasesAdditionalInformationDetail Leases - Additional Information (Detail) Details 45 false false R46.htm 100490 - Disclosure - Leases - Summary of Components of Operating Lease Expense (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureLeasesSummaryOfComponentsOfOperatingLeaseExpenseDetail Leases - Summary of Components of Operating Lease Expense (Detail) Details 46 false false R47.htm 100510 - Disclosure - Leases - Summary of Supplemental Cash Flow Information Related to Operating Leases (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureLeasesSummaryOfSupplementalCashFlowInformationRelatedToOperatingLeasesDetail Leases - Summary of Supplemental Cash Flow Information Related to Operating Leases (Detail) Details 47 false false R48.htm 100520 - Disclosure - Leases - Summary of Lease Balances Related to Operating and Finance Leases Except Weighted Average Remaining Lease Term And Discount Rate (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureLeasesSummaryOfLeaseBalancesRelatedToOperatingAndFinanceLeasesExceptWeightedAverageRemainingLeaseTermAndDiscountRateDetail Leases - Summary of Lease Balances Related to Operating and Finance Leases Except Weighted Average Remaining Lease Term And Discount Rate (Detail) Details 48 false false R49.htm 100530 - Disclosure - Leases - Summary of Maturity of Operating Lease Liabilities (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureLeasesSummaryOfMaturityOfOperatingLeaseLiabilitiesDetail Leases - Summary of Maturity of Operating Lease Liabilities (Detail) Details 49 false false R50.htm 100540 - Disclosure - Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureAccruedExpensesAndOtherCurrentLiabilitiesScheduleOfAccruedExpensesAndOtherCurrentLiabilitiesDetail Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Detail) Details 50 false false R51.htm 100550 - Disclosure - Equity Transactions - Underwritten Public Offering - Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureEquityTransactionsUnderwrittenPublicOfferingAdditionalInformationDetail Equity Transactions - Underwritten Public Offering - Additional Information (Detail) Details 51 false false R52.htm 100560 - Disclosure - Equity Transactions - Rights Offering - Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureEquityTransactionsRightsOfferingAdditionalInformationDetail Equity Transactions - Rights Offering - Additional Information (Detail) Details 52 false false R53.htm 100570 - Disclosure - Equity - Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureEquityAdditionalInformationDetail Equity - Additional Information (Detail) Details 53 false false R54.htm 100580 - Disclosure - Share-Based Compensation - Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensationAdditionalInformationDetail Share-Based Compensation - Additional Information (Detail) Details 54 false false R55.htm 100590 - Disclosure - Share-Based Compensation - Summary of Stock Option Activity (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensationSummaryOfStockOptionActivityDetail Share-Based Compensation - Summary of Stock Option Activity (Detail) Details 55 false false R56.htm 100600 - Disclosure - Share-Based Compensation - Summary of Activity of Options and RSUs of Performance-Based Options (Details) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensationSummaryOfActivityOfOptionsAndRsusOfPerformanceBasedOptionsDetails Share-Based Compensation - Summary of Activity of Options and RSUs of Performance-Based Options (Details) Details 56 false false R57.htm 100610 - Disclosure - Share-Based Compensation - Summary of Assumptions Used to Determine Fair Value of Stock Option Awards Granted to Employees and Directors (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensationSummaryOfAssumptionsUsedToDetermineFairValueOfStockOptionAwardsGrantedToEmployeesAndDirectorsDetail Share-Based Compensation - Summary of Assumptions Used to Determine Fair Value of Stock Option Awards Granted to Employees and Directors (Detail) Details 57 false false R58.htm 100620 - Disclosure - Share-Based Compensation - Summary of Stock Option Granted Under Equity Incentive Plans (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensationSummaryOfStockOptionGrantedUnderEquityIncentivePlansDetail Share-Based Compensation - Summary of Stock Option Granted Under Equity Incentive Plans (Detail) Details 58 false false R59.htm 100630 - Disclosure - Share-Based Compensation - Summary of Share-Based Compensation Expense (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureShareBasedCompensationSummaryOfShareBasedCompensationExpenseDetail Share-Based Compensation - Summary of Share-Based Compensation Expense (Detail) Details 59 false false R60.htm 100640 - Disclosure - Share-Based Compensation - Restricted Stock Units (Details) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/DisclosureSharebasedCompensationRestrictedStockUnitsDetails Share-Based Compensation - Restricted Stock Units (Details) Details 60 false false R61.htm 100650 - Disclosure - Liability Related to the Sale of Future Royalties- Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/DisclosureLiabilityRelatedToTheSaleOfFutureRoyaltiesAdditionalInformationDetail Liability Related to the Sale of Future Royalties- Additional Information (Detail) Details 61 false false R62.htm 100660 - Disclosure - Liability Related to the Sale of Future Royalties - Schedule of Changes in the Liability Related to the Sale of Future Royalties (Details) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/DisclosureLiabilityRelatedToTheSaleOfFutureRoyaltiesScheduleOfChangesInTheLiabilityRelatedToTheSaleOfFutureRoyaltiesDetails Liability Related to the Sale of Future Royalties - Schedule of Changes in the Liability Related to the Sale of Future Royalties (Details) Details 62 false false R63.htm 100670 - Disclosure - Non-Controlling Interests - Spero Gyrase - Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureNonControllingInterestsSperoGyraseAdditionalInformationDetail Non-Controlling Interests - Spero Gyrase - Additional Information (Detail) Details 63 false false R64.htm 100680 - Disclosure - Restructuring (Additional Information) (Details) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/DisclosureRestructuringAdditionalInformationDetails Restructuring (Additional Information) (Details) Details http://sperotherapeutics.com/20221231/taxonomy/role/DisclosureRestructuringTables 64 false false R65.htm 100690 - Disclosure - Restructuring - Restructuring charges (Details) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/DisclosureRestructuringRestructuringChargesDetails Restructuring - Restructuring charges (Details) Details 65 false false R66.htm 100700 - Disclosure - Restructuring - Schedule of Restructuring charges included in Accrued expenses and other current liabilities (Details) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/DisclosureRestructuringScheduleOfRestructuringChargesIncludedInAccruedExpensesAndOtherCurrentLiabilitiesDetails Restructuring - Schedule of Restructuring charges included in Accrued expenses and other current liabilities (Details) Details 66 false false R67.htm 100710 - Disclosure - Income Taxes - Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesAdditionalInformationDetail Income Taxes - Additional Information (Detail) Details 67 false false R68.htm 100720 - Disclosure - Income Taxes - Schedule of Domestic and Foreign Components of Loss before Income Taxes (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesScheduleOfDomesticAndForeignComponentsOfLossBeforeIncomeTaxesDetail Income Taxes - Schedule of Domestic and Foreign Components of Loss before Income Taxes (Detail) Details 68 false false R69.htm 100730 - Disclosure - Income Taxes - Reconciliation of U.S. Federal Statutory Income Tax Rate to Company's Effective Income Tax Rate (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesReconciliationOfUSFederalStatutoryIncomeTaxRateToCompanySEffectiveIncomeTaxRateDetail Income Taxes - Reconciliation of U.S. Federal Statutory Income Tax Rate to Company's Effective Income Tax Rate (Detail) Details 69 false false R70.htm 100740 - Disclosure - Income Taxes - Net Deferred Tax Assets (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesNetDeferredTaxAssetsDetail Income Taxes - Net Deferred Tax Assets (Detail) Details 70 false false R71.htm 100750 - Disclosure - Income Taxes - Summary of Changes in Valuation Allowance for Deferred Tax Assets (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesSummaryOfChangesInValuationAllowanceForDeferredTaxAssetsDetail Income Taxes - Summary of Changes in Valuation Allowance for Deferred Tax Assets (Detail) Details 71 false false R72.htm 100760 - Disclosure - Government Contracts - Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureGovernmentContractsAdditionalInformationDetail Government Contracts - Additional Information (Detail) Details 72 false false R73.htm 100770 - Disclosure - License, Collaboration and Service Agreements - Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureLicenseCollaborationAndServiceAgreementsAdditionalInformationDetail License, Collaboration and Service Agreements - Additional Information (Detail) Details 73 false false R74.htm 100780 - Disclosure - License, Collaboration and Service Agreements - Schedule of remaining potential milestone payments (Details) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/DisclosureLicenseCollaborationAndServiceAgreementsScheduleOfRemainingPotentialMilestonePaymentsDetails License, Collaboration and Service Agreements - Schedule of remaining potential milestone payments (Details) Details 74 false false R75.htm 100810 - Disclosure - Net Loss per Share - Summary of Basic and Diluted Net Loss per Share Attributable to Common Stockholders (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureNetLossPerShareSummaryOfBasicAndDilutedNetLossPerShareAttributableToCommonStockholdersDetail Net Loss per Share - Summary of Basic and Diluted Net Loss per Share Attributable to Common Stockholders (Detail) Details 75 false false R76.htm 100830 - Disclosure - Net Loss per Share - Summary of Shares Excluded From the Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureNetLossPerShareSummaryOfSharesExcludedFromComputationOfDilutedNetLossPerShareAttributableToCommonStockholdersDetail Net Loss per Share - Summary of Shares Excluded From the Computation of Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) Details 76 false false R77.htm 100840 - Disclosure - Retirement Plan - Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureRetirementPlanAdditionalInformationDetail Retirement Plan - Additional Information (Detail) Details 77 false false R78.htm 100850 - Disclosure - Subsequent Events - Additional Information (Detail) Sheet http://sperotherapeutics.com/20221231/taxonomy/role/Role_DisclosureSubsequentEventsAdditionalInformationDetail Subsequent Events - Additional Information (Detail) Details 78 false false All Reports Book All Reports [ix-0514-Hidden-Fact-Eligible-For-Transform] WARN: 15 fact(s) appearing in ix:hidden were eligible for transformation: dei:CurrentFiscalYearEndDate, us-gaap:ChangeInAccountingPrincipleAccountingStandardsUpdateAdopted, us-gaap:ChangeInAccountingPrincipleAccountingStandardsUpdateImmaterialEffect, us-gaap:LesseeOperatingLeaseExistenceOfOptionToExtend - spro-20221231.htm 8 spro-20221231.htm spro-20221231.xsd spro-20221231_cal.xml spro-20221231_def.xml spro-20221231_lab.xml spro-20221231_pre.xml spro-ex10_4.htm spro-ex10_5.htm spro-ex10_6.htm spro-ex23_1.htm spro-ex31_1.htm spro-ex31_2.htm spro-ex32.htm spro-ex4_2.htm img161168720_0.jpg img161168720_1.jpg img161168720_2.jpg http://fasb.org/us-gaap/2022 http://xbrl.sec.gov/dei/2022 true true