3.23.1 html 166 359 1 false 44 0 false 7 false false R1.htm 100000 - Document - Document and Entity Information Sheet http://boltbio.com/20221231/taxonomy/role/Role_DocumentDocumentAndEntityInformation Document and Entity Information Cover 1 false false R2.htm 100010 - Statement - BALANCE SHEETS Sheet http://boltbio.com/20221231/taxonomy/role/StatementBalanceSheets BALANCE SHEETS Statements 2 false false R3.htm 100020 - Statement - BALANCE SHEETS (Parenthetical) Sheet http://boltbio.com/20221231/taxonomy/role/StatementBalanceSheetsParenthetical BALANCE SHEETS (Parenthetical) Statements 3 false false R4.htm 100030 - Statement - STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS Sheet http://boltbio.com/20221231/taxonomy/role/StatementStatementsOfOperationsAndComprehensiveLoss STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS Statements 4 false false R5.htm 100040 - Statement - STATEMENTS OF PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) Sheet http://boltbio.com/20221231/taxonomy/role/StatementStatementsOfPreferredStockAndStockholdersEquityDeficit1 STATEMENTS OF PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) Statements 5 false false R6.htm 100050 - Statement - STATEMENTS OF PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (Parenthetical) Sheet http://boltbio.com/20221231/taxonomy/role/StatementStatementsOfPreferredStockAndStockholdersEquityDeficitParenthetical STATEMENTS OF PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (Parenthetical) Statements 6 false false R7.htm 100060 - Statement - STATEMENTS OF CASH FLOWS Sheet http://boltbio.com/20221231/taxonomy/role/StatementStatementsOfCashFlows STATEMENTS OF CASH FLOWS Statements 7 false false R8.htm 100070 - Disclosure - Description of the Business Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureDescriptionOfBusiness Description of the Business Notes 8 false false R9.htm 100080 - Disclosure - Summary of Significant Accounting Policies Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPolicies Summary of Significant Accounting Policies Notes 9 false false R10.htm 100090 - Disclosure - Fair Value Measurements and Fair Value of Financial Instruments Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsAndFairValueOfFinancialInstruments Fair Value Measurements and Fair Value of Financial Instruments Notes 10 false false R11.htm 100100 - Disclosure - License and Equity Agreement Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureLicenseAndEquityAgreement License and Equity Agreement Notes 11 false false R12.htm 100110 - Disclosure - Balance Sheet Components Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureBalanceSheetComponents Balance Sheet Components Notes 12 false false R13.htm 100120 - Disclosure - Collaborations Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureCollaborations Collaborations Notes 13 false false R14.htm 100130 - Disclosure - Commitment and Contingencies Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureCommitmentAndContingencies Commitment and Contingencies Notes 14 false false R15.htm 100140 - Disclosure - Convertible Preferred Stock Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureConvertiblePreferredStock Convertible Preferred Stock Notes 15 false false R16.htm 100150 - Disclosure - Common Stock Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureCommonStock Common Stock Notes 16 false false R17.htm 100160 - Disclosure - Stock-Based Compensation Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureStockBasedCompensation Stock-Based Compensation Notes 17 false false R18.htm 100170 - Disclosure - Net Loss Per Share Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureNetLossPerShare Net Loss Per Share Notes 18 false false R19.htm 100180 - Disclosure - 401(K) Savings Plan Sheet http://boltbio.com/20221231/taxonomy/role/Disclosure401kSavingsPlan 401(K) Savings Plan Notes 19 false false R20.htm 100190 - Disclosure - Income Taxes Sheet http://boltbio.com/20221231/taxonomy/role/DisclosureIncomeTaxes Income Taxes Notes 20 false false R21.htm 100210 - Disclosure - Summary of Significant Accounting Policies (Policies) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPoliciesPolicies Summary of Significant Accounting Policies (Policies) Policies http://boltbio.com/20221231/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPolicies 21 false false R22.htm 100220 - Disclosure - Fair Value Measurements and Fair Value of Financial Instruments (Tables) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsAndFairValueOfFinancialInstrumentsTables Fair Value Measurements and Fair Value of Financial Instruments (Tables) Tables http://boltbio.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsAndFairValueOfFinancialInstruments 22 false false R23.htm 100230 - Disclosure - Balance Sheet Components (Tables) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureBalanceSheetComponentsTables Balance Sheet Components (Tables) Tables http://boltbio.com/20221231/taxonomy/role/Role_DisclosureBalanceSheetComponents 23 false false R24.htm 100240 - Disclosure - Collaborations (Tables) Sheet http://boltbio.com/20221231/taxonomy/role/DisclosureCollaborationsTables Collaborations (Tables) Tables http://boltbio.com/20221231/taxonomy/role/Role_DisclosureCollaborations 24 false false R25.htm 100250 - Disclosure - Commitment and Contingencies (Tables) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureCommitmentAndContingenciesTables Commitment and Contingencies (Tables) Tables http://boltbio.com/20221231/taxonomy/role/Role_DisclosureCommitmentAndContingencies 25 false false R26.htm 100260 - Disclosure - Common Stock (Tables) Sheet http://boltbio.com/20221231/taxonomy/role/DisclosureCommonStockTables Common Stock (Tables) Tables http://boltbio.com/20221231/taxonomy/role/Role_DisclosureCommonStock 26 false false R27.htm 100270 - Disclosure - Stock-Based Compensation (Tables) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureStockBasedCompensationTables Stock-Based Compensation (Tables) Tables http://boltbio.com/20221231/taxonomy/role/Role_DisclosureStockBasedCompensation 27 false false R28.htm 100280 - Disclosure - Net Loss Per Share (Tables) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureNetLossPerShareTables Net Loss Per Share (Tables) Tables http://boltbio.com/20221231/taxonomy/role/Role_DisclosureNetLossPerShare 28 false false R29.htm 100290 - Disclosure - Income Taxes (Tables) Sheet http://boltbio.com/20221231/taxonomy/role/DisclosureIncomeTaxesTables Income Taxes (Tables) Tables http://boltbio.com/20221231/taxonomy/role/DisclosureIncomeTaxes 29 false false R30.htm 100300 - Disclosure - Description of the Business - Additional Information (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureDescriptionOfBusinessAdditionalInformationDetails Description of the Business - Additional Information (Details) Details 30 false false R31.htm 100310 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetails Summary of Significant Accounting Policies - Additional Information (Details) Details 31 false false R32.htm 100320 - Disclosure - Fair Value Measurements and Fair Value of Financial Instruments - Additional Information (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsAndFairValueOfFinancialInstrumentsAdditionalInformationDetails Fair Value Measurements and Fair Value of Financial Instruments - Additional Information (Details) Details 32 false false R33.htm 100330 - Disclosure - Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Marketable Securities Classified as Available-for-sale Securities (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsAndFairValueOfFinancialInstrumentsScheduleOfMarketableSecuritiesClassifiedAsAvailableForSaleSecuritiesDetails Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Marketable Securities Classified as Available-for-sale Securities (Details) Details 33 false false R34.htm 100340 - Disclosure - Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Fair Values of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureFairValueMeasurementsAndFairValueOfFinancialInstrumentsScheduleOfFairValuesOfAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisDetails Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Fair Values of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) Details 34 false false R35.htm 100350 - Disclosure - License and Equity Agreement - Additional Information (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureLicenseAndEquityAgreementAdditionalInformationDetails License and Equity Agreement - Additional Information (Details) Details 35 false false R36.htm 100360 - Disclosure - Balance Sheet Components - Property and Equipment, Net (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureBalanceSheetComponentsPropertyAndEquipmentNetDetails Balance Sheet Components - Property and Equipment, Net (Details) Details 36 false false R37.htm 100370 - Disclosure - Balance Sheet Components - Additional Information (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureBalanceSheetComponentsAdditionalInformationDetails Balance Sheet Components - Additional Information (Details) Details 37 false false R38.htm 100380 - Disclosure - Balance Sheet Components - Accrued Expenses and Other Current Liabilities (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureBalanceSheetComponentsAccruedExpensesAndOtherCurrentLiabilitiesDetails Balance Sheet Components - Accrued Expenses and Other Current Liabilities (Details) Details 38 false false R39.htm 100390 - Disclosure - Collaborations - Additional Information (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureCollaborationsAdditionalInformationDetails Collaborations - Additional Information (Details) Details 39 false false R40.htm 100400 - Disclosure - Collaborations - Schedule of Changes in Contract Liability (Details) Sheet http://boltbio.com/20221231/taxonomy/role/DisclosureCollaborationsScheduleOfChangesInContractLiabilityDetails Collaborations - Schedule of Changes in Contract Liability (Details) Details 40 false false R41.htm 100420 - Disclosure - Commitments and Contingencies - Additional Information (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureCommitmentsAndContingenciesAdditionalInformationDetails Commitments and Contingencies - Additional Information (Details) Details 41 false false R42.htm 100430 - Disclosure - Commitments and Contingencies - Components of Lease Expense (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureCommitmentsAndContingenciesComponentsOfLeaseExpenseDetails Commitments and Contingencies - Components of Lease Expense (Details) Details 42 false false R43.htm 100440 - Disclosure - Commitments and Contingencies - Supplemental Cash Flow Information Related to Cash Paid for Amounts Included in the Measurement of Lease Liabilities (Details) Sheet http://boltbio.com/20221231/taxonomy/role/DisclosureCommitmentsAndContingenciesSupplementalCashFlowInformationRelatedToCashPaidForAmountsIncludedInTheMeasurementOfLeaseLiabilities Commitments and Contingencies - Supplemental Cash Flow Information Related to Cash Paid for Amounts Included in the Measurement of Lease Liabilities (Details) Details 43 false false R44.htm 100450 - Disclosure - Commitments and Contingencies - Schedule by Year for Future Maturities of Operating Lease Liabilities and Sublease Income to be Received (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureCommitmentsAndContingenciesScheduleByYearForFutureMaturitiesOfOperatingLeaseLiabilitiesAndSubleaseIncomeToBeReceivedDetails Commitments and Contingencies - Schedule by Year for Future Maturities of Operating Lease Liabilities and Sublease Income to be Received (Details) Details 44 false false R45.htm 100460 - Disclosure - Convertible Preferred Stock - Additional Information (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureConvertiblePreferredStockAdditionalInformationDetails Convertible Preferred Stock - Additional Information (Details) Details 45 false false R46.htm 100470 - Disclosure - Common Stock - Additional Information (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureCommonStockAdditionalInformationDetails Common Stock - Additional Information (Details) Details 46 false false R47.htm 100480 - Disclosure - Common Stock - Schedule of Common Stock Reserved for Future Issuance (Details) Sheet http://boltbio.com/20221231/taxonomy/role/DisclosureCommonStockScheduleOfCommonStockReservedForFutureIssuanceDetails Common Stock - Schedule of Common Stock Reserved for Future Issuance (Details) Details 47 false false R48.htm 100490 - Disclosure - Stock-Based Compensation - Additional Information (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureStockBasedCompensationAdditionalInformationDetails Stock-Based Compensation - Additional Information (Details) Details 48 false false R49.htm 100500 - Disclosure - Stock-Based Compensation - Summary of Stock Option Activity (Details) Sheet http://boltbio.com/20221231/taxonomy/role/DisclosureStockbasedCompensationSummaryOfStockOptionActivityDetails Stock-Based Compensation - Summary of Stock Option Activity (Details) Details 49 false false R50.htm 100510 - Disclosure - Stock-Based Compensation - Summary of Fair Value of Option Grant Estimated Using Black-Scholes Option-Pricing Model (Details) Sheet http://boltbio.com/20221231/taxonomy/role/DisclosureStockbasedCompensationSummaryOfFairValueOfOptionGrantEstimatedUsingBlackscholesOptionpricingModelDetails Stock-Based Compensation - Summary of Fair Value of Option Grant Estimated Using Black-Scholes Option-Pricing Model (Details) Details 50 false false R51.htm 100520 - Disclosure - Stock-Based Compensation - Summary of Components of Stock-Based Compensation Expense Recognized (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureStockBasedCompensationSummaryOfComponentsOfStockBasedCompensationExpenseRecognizedDetails Stock-Based Compensation - Summary of Components of Stock-Based Compensation Expense Recognized (Details) Details 51 false false R52.htm 100530 - Disclosure - Stock-Based Compensation - Summary of Restricted Stock Awards Activity (Details) Sheet http://boltbio.com/20221231/taxonomy/role/DisclosureStockbasedCompensationSummaryOfRestrictedStockAwardsActivityDetails Stock-Based Compensation - Summary of Restricted Stock Awards Activity (Details) Details 52 false false R53.htm 100550 - Disclosure - Net Loss Per Share - Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders, which excludes Shares Legally Outstanding (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureNetLossPerShareComputationOfBasicAndDilutedNetLossPerShareAttributableToCommonStockholdersWhichExcludesSharesLegallyOutstandingDetails Net Loss Per Share - Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders, which excludes Shares Legally Outstanding (Details) Details 53 false false R54.htm 100560 - Disclosure - Net Loss Per Share - Potentially Dilutive Securities not Included in the Calculation of Diluted Net Loss per Share (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Role_DisclosureNetLossPerSharePotentiallyDilutiveSecuritiesNotIncludedInCalculationOfDilutedNetLossPerShareDetails Net Loss Per Share - Potentially Dilutive Securities not Included in the Calculation of Diluted Net Loss per Share (Details) Details 54 false false R55.htm 100570 - Disclosure - 401(K) Savings Plan - Additional Information (Details) Sheet http://boltbio.com/20221231/taxonomy/role/Disclosure401kSavingsPlanAdditionalInformationDetails 401(K) Savings Plan - Additional Information (Details) Details 55 false false R56.htm 100580 - Disclosure - Income Taxes - Additional Information (Details) Sheet http://boltbio.com/20221231/taxonomy/role/DisclosureIncomeTaxesAdditionalInformationDetails Income Taxes - Additional Information (Details) Details 56 false false R57.htm 100590 - Disclosure - Income Taxes - Summary of Reconciliation of Effective Tax Rate and Federal Statutory Tax Rate (Details) Sheet http://boltbio.com/20221231/taxonomy/role/DisclosureIncomeTaxesSummaryOfReconciliationOfEffectiveTaxRateAndFederalStatutoryTaxRateDetails Income Taxes - Summary of Reconciliation of Effective Tax Rate and Federal Statutory Tax Rate (Details) Details 57 false false R58.htm 100600 - Disclosure - Income Taxes - Summary of Significant Components of Deferred Tax Assets and Liabilities for Federal and State Income Taxes (Details) Sheet http://boltbio.com/20221231/taxonomy/role/DisclosureIncomeTaxesSummaryOfSignificantComponentsOfDeferredTaxAssetsAndLiabilitiesForFederalAndStateIncomeTaxesDetails Income Taxes - Summary of Significant Components of Deferred Tax Assets and Liabilities for Federal and State Income Taxes (Details) Details 58 false false R59.htm 100610 - Disclosure - Income Taxes - Summary of Gross Unrecognized Tax Benefits (Details) Sheet http://boltbio.com/20221231/taxonomy/role/DisclosureIncomeTaxesSummaryOfGrossUnrecognizedTaxBenefitsDetails Income Taxes - Summary of Gross Unrecognized Tax Benefits (Details) Details 59 false false R60.htm 100620 - Disclosure - Subsequent Events - Additional Information (Details) Sheet http://boltbio.com/20221231/taxonomy/role/DisclosureSubsequentEventsAdditionalInformationDetails Subsequent Events - Additional Information (Details) Details 60 false false All Reports Book All Reports bolt-20221231.htm bolt-20221231.xsd bolt-20221231_cal.xml bolt-20221231_def.xml bolt-20221231_lab.xml bolt-20221231_pre.xml bolt-ex10_24.htm bolt-ex10_25.htm bolt-ex23_1.htm bolt-ex31_1.htm bolt-ex31_2.htm bolt-ex32_1.htm bolt-ex32_2.htm img55127669_0.jpg http://fasb.org/us-gaap/2022 http://xbrl.sec.gov/dei/2022 true true