3.23.2 html 144 228 1 false 28 0 false 6 false false R1.htm 100000 - Document - Document and Entity Information Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DocumentDocumentAndEntityInformation Document and Entity Information Cover 1 false false R2.htm 100010 - Statement - Condensed Balance Sheets (unaudited) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/StatementCondensedBalanceSheetsUnaudited Condensed Balance Sheets (unaudited) Statements 2 false false R3.htm 100030 - Statement - Condensed Balance Sheets (unaudited) (Parenthetical) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/StatementCondensedBalanceSheetsUnauditedParenthetical Condensed Balance Sheets (unaudited) (Parenthetical) Statements 3 false false R4.htm 100040 - Statement - Condensed Statements of Operations and Comprehensive Loss (unaudited) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/StatementCondensedStatementsOfOperationsAndComprehensiveLossUnaudited Condensed Statements of Operations and Comprehensive Loss (unaudited) Statements 4 false false R5.htm 100050 - Statement - Condensed Statements of Cash Flows (unaudited) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/StatementCondensedStatementsOfCashFlowsUnaudited Condensed Statements of Cash Flows (unaudited) Statements 5 false false R6.htm 100060 - Disclosure - Organization and Basis of Presentation Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureOrganizationAndBasisOfPresentation Organization and Basis of Presentation Notes 6 false false R7.htm 100070 - Disclosure - Summary of Significant Accounting Policies Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPolicies Summary of Significant Accounting Policies Notes 7 false false R8.htm 100080 - Disclosure - Fair Value Measurements Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureFairValueMeasurements Fair Value Measurements Notes 8 false false R9.htm 100090 - Disclosure - Short-Term Investments Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureShorttermInvestments Short-Term Investments Notes 9 false false R10.htm 100100 - Disclosure - Accrued Other Expenses Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureAccruedOtherExpenses Accrued Other Expenses Notes 10 false false R11.htm 100110 - Disclosure - Stockholders' Equity Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureStockholdersEquity Stockholders' Equity Notes 11 false false R12.htm 100120 - Disclosure - License Agreement with Arena Pharmaceuticals, Inc. Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureLicenseAgreementWithArenaPharmaceuticalsInc License Agreement with Arena Pharmaceuticals, Inc. Notes 12 false false R13.htm 100130 - Disclosure - Stock-Based Compensation Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureStockBasedCompensation Stock-Based Compensation Notes 13 false false R14.htm 100140 - Disclosure - Commitments and Contingencies Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureCommitmentsAndContingencies Commitments and Contingencies Notes 14 false false R15.htm 100150 - Disclosure - Employment Benefits Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureEmploymentBenefits Employment Benefits Notes 15 false false R16.htm 100160 - Disclosure - Summary of Significant Accounting Policies (Policies) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPoliciesPolicies Summary of Significant Accounting Policies (Policies) Policies http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPolicies 16 false false R17.htm 100170 - Disclosure - Summary of Significant Accounting Policies (Tables) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPoliciesTables Summary of Significant Accounting Policies (Tables) Tables http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPolicies 17 false false R18.htm 100180 - Disclosure - Fair Value Measurements (Tables) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureFairValueMeasurementsTables Fair Value Measurements (Tables) Tables http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureFairValueMeasurements 18 false false R19.htm 100190 - Disclosure - Short-Term Investments (Tables) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureShorttermInvestmentsTables Short-Term Investments (Tables) Tables http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureShorttermInvestments 19 false false R20.htm 100200 - Disclosure - Accrued Other Expenses (Tables) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureAccruedOtherExpensesTables Accrued Other Expenses (Tables) Tables http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureAccruedOtherExpenses 20 false false R21.htm 100210 - Disclosure - Stockholders' Equity (Tables) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureStockholdersEquityTables Stockholders' Equity (Tables) Tables http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureStockholdersEquity 21 false false R22.htm 100230 - Disclosure - Stock-Based Compensation (Tables) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureStockBasedCompensationTables Stock-Based Compensation (Tables) Tables http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureStockBasedCompensation 22 false false R23.htm 100240 - Disclosure - Commitments and Contingencies (Tables) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureCommitmentsAndContingenciesTables Commitments and Contingencies (Tables) Tables http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureCommitmentsAndContingencies 23 false false R24.htm 100250 - Disclosure - Organization and Basis of Presentation - Additional Information (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureOrganizationAndBasisOfPresentationAdditionalInformationDetails Organization and Basis of Presentation - Additional Information (Details) Details 24 false false R25.htm 100260 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetails Summary of Significant Accounting Policies - Additional Information (Details) Details 25 false false R26.htm 100270 - Disclosure - Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureSummaryOfSignificantAccountingPoliciesScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareDetails Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) Details 26 false false R27.htm 100280 - Disclosure - Fair Value Measurements - Summary of Company's Financial Assets Recognized at Fair Value (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureFairValueMeasurementsSummaryOfCompanysFinancialAssetsRecognizedAtFairValueDetails Fair Value Measurements - Summary of Company's Financial Assets Recognized at Fair Value (Details) Details 27 false false R28.htm 100290 - Disclosure - Short-Term Investments - Summary of Short-Term Investments (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureShorttermInvestmentsSummaryOfShorttermInvestmentsDetails Short-Term Investments - Summary of Short-Term Investments (Details) Details 28 false false R29.htm 100310 - Disclosure - Short-Term Investments - Summary of Maturity of the Short-Term Investments (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureShorttermInvestmentsSummaryOfMaturityOfTheShorttermInvestmentsDetails Short-Term Investments - Summary of Maturity of the Short-Term Investments (Details) Details 29 false false R30.htm 100320 - Disclosure - Short-Term Investments - Summary of Available-for-sale Investments (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureShorttermInvestmentsSummaryOfAvailableforsaleInvestmentsDetails Short-Term Investments - Summary of Available-for-sale Investments (Details) Details 30 false false R31.htm 100330 - Disclosure - Accrued Other Expenses - Summary of Accrued Other Expenses (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureAccruedOtherExpensesSummaryOfAccruedOtherExpensesDetails Accrued Other Expenses - Summary of Accrued Other Expenses (Details) Details 31 false false R32.htm 100350 - Disclosure - Stockholders' Equity - Additional Information (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureStockholdersEquityAdditionalInformationDetails Stockholders' Equity - Additional Information (Details) Details 32 false false R33.htm 100360 - Disclosure - Stockholders' Equity - Schedule of Changes in Convertible Preferred Stock and Stockholders' Equity (Deficit) (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureStockholdersEquityScheduleOfChangesInConvertiblePreferredStockAndStockholdersEquityDeficitDetails Stockholders' Equity - Schedule of Changes in Convertible Preferred Stock and Stockholders' Equity (Deficit) (Details) Details 33 false false R34.htm 100380 - Disclosure - Stock-Based Compensation - Additional Information (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureStockbasedCompensationAdditionalInformationDetails Stock-Based Compensation - Additional Information (Details) Details 34 false false R35.htm 100390 - Disclosure - Stock-Based Compensation - Summary of Stock Option Activity (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureStockbasedCompensationSummaryOfStockOptionActivityDetails Stock-Based Compensation - Summary of Stock Option Activity (Details) Details 35 false false R36.htm 100400 - Disclosure - Stock-Based Compensation - Summary of Weighted Average Grant-Date Fair Values And Weighted Average Assumptions Used to Calculate Fair Value of Options Granted (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureStockbasedCompensationSummaryOfWeightedAverageGrantdateFairValuesAndWeightedAverageAssumptionsUsedToCalculateFairValueOfOptions Stock-Based Compensation - Summary of Weighted Average Grant-Date Fair Values And Weighted Average Assumptions Used to Calculate Fair Value of Options Granted (Details) Details 36 false false R37.htm 100410 - Disclosure - Stock-Based Compensation Expense - Schedule of Stock-Based Compensation Expense Recognized for all Equity Awards and Reported in the Statements of Operations and Comprehensive Loss (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureStockbasedCompensationExpenseScheduleOfStockbasedCompensationExpenseRecognizedForAllEquityAwardsAndReportedInTheStatementsOfOper Stock-Based Compensation Expense - Schedule of Stock-Based Compensation Expense Recognized for all Equity Awards and Reported in the Statements of Operations and Comprehensive Loss (Details) Details 37 false false R38.htm 100420 - Disclosure - Commitments and Contingencies - Additional Information (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureCommitmentsAndContingenciesAdditionalInformationDetails Commitments and Contingencies - Additional Information (Details) Details 38 false false R39.htm 100430 - Disclosure - Commitments and Contingencies - Schedule of Supplemental Cash Flow Information Related to Leases (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureCommitmentsAndContingenciesScheduleOfSupplementalCashFlowInformationRelatedToLeasesDetails Commitments and Contingencies - Schedule of Supplemental Cash Flow Information Related to Leases (Details) Details 39 false false R40.htm 100440 - Disclosure - Commitments and Contingencies - Schedule of Supplemental Balance Sheet Information Related to Leases (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureCommitmentsAndContingenciesScheduleOfSupplementalBalanceSheetInformationRelatedToLeasesDetails Commitments and Contingencies - Schedule of Supplemental Balance Sheet Information Related to Leases (Details) Details 40 false false R41.htm 100450 - Disclosure - Commitments and Contingencies - Schedule of Future Minimum Lease Commitments (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/DisclosureCommitmentsAndContingenciesScheduleOfFutureMinimumLeaseCommitmentsDetails Commitments and Contingencies - Schedule of Future Minimum Lease Commitments (Details) Details 41 false false R42.htm 100460 - Disclosure - Employment Benefits - Additional Information (Details) Sheet http://www.longboardpharma.com/20230630/taxonomy/role/Role_DisclosureEmploymentBenefitsAdditionalInformationDetails Employment Benefits - Additional Information (Details) Details 42 false false All Reports Book All Reports [ix-0514-Hidden-Fact-Eligible-For-Transform] WARN: 1 fact(s) appearing in ix:hidden were eligible for transformation: us-gaap:ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1 - lbph-20230630.htm 8 lbph-20230630.htm lbph-20230630.xsd lbph-20230630_cal.xml lbph-20230630_def.xml lbph-20230630_lab.xml lbph-20230630_pre.xml lbph-ex10_1.htm lbph-ex31_1.htm lbph-ex31_2.htm lbph-ex32_1.htm img9517409_0.jpg http://fasb.org/us-gaap/2022 http://xbrl.sec.gov/dei/2022 true true