Document And Entity Information
Dividend yield
Note To Financial Statement Details Textual
Significant Accounting Policies
Note 2 - Summary of Significant Accounting Policies
Note 3 - Business Combination
Risk-free interest rate
Unrealized gain (loss) on available-for-sale investments, net of tax
us-gaap_GrantsReceivable
Grants Receivable
Note 4 - Fair Value of Financial Instruments
Note 5 - Balance Sheet Components
Note 7 - Liabilities Related to Sale of Future Royalties
Note 8 - Leases
The September 2021 ATM [Member]
Related to the September 2021 ATM.
Note 10 - Stockholders' Equity
South San Francisco Real Estate [Member]
Related to South San Francisco real estate.
Note 11 - Equity Incentive Plans
Unrealized loss on available-for-sale investments
Facility in South San Francisco [Member]
Related to facility in South San Francisco.
Income Tax Disclosure [Text Block]
Note 13 - Income Taxes
Note 14 - Net Loss Per Share
Note 2 - Summary of Significant Accounting Policies - Estimated Useful Lives (Details)
Expected volatility
Note 3 - Business Combination - Allocation of the Purchase Price to the Fair Value of the Respective Assets and Liabilities Acquired (Details)
us-gaap_LiabilitiesCurrent
Total current liabilities
Note 4 - Fair Value of Financial Instruments - Financial Assets Measured on a Recurring Basis (Details)
Note 5 - Balance Sheet Components - Cash and Cash Equivalents and Investments (Details)
Note 5 - Balance Sheet Components - Property and Equipment, Net (Details)
Note 5 - Balance Sheet Components - Intangible Assets (Details)
Expected term (in years) (Year)
Note 5 - Balance Sheet Components - Estimated Future Amortization Expense (Details)
Note 5 - Balance Sheet Components - Accrued Liabilities (Details)
Note 7 - Liabilities Related to Sale of Future Royalties - Deferred Revenue Activity (Details)
us-gaap_BusinessCombinationConsiderationTransferred1
Business Combination, Consideration Transferred, Total
Note 8 - Leases - Lease Liabilities Payment Obligations (Details)
Note 8 - Leases - Operating Lease Expenses (Details)
Schedule of Share-Based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]
Note 10 - Stockholders' Equity - Shares of Common Stock Reserved for Issuance (Details)
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]
Note 10 - Stockholders' Equity - Summary of Warrants Outstanding (Details)
Note 11 - Equity Incentive Plans - Summary of Stock Option Transactions (Details)
Note 11 - Equity Incentive Plans - Assumptions of Options (Details)
Note 11 - Equity Incentive Plans - Total Stock-based Compensation Recognized for Options (Details)
us-gaap_LitigationSettlementAmountAwardedToOtherParty
Litigation Settlement, Amount Awarded to Other Party
Note 11 - Equity Incentive Plans - Assumptions of Employee Purchase Plan (Details)
Share-Based Payment Arrangement, Option, Activity [Table Text Block]
Note 13 - Income Taxes - Components of Income Tax Expense (Details)
Note 13 - Income Taxes - Components of Deferred Tax Assets (Details)
Note 13 - Income Taxes - Reconciliation of Effective Tax Rate (Details)
Note 13 - Income Taxes - Unrecognized Tax Benefits (Details)
Note 14 - Net Loss Per Share Attributable to Common Stockholders - Calculation of Basic and Diluted Net (Loss) Income Per Share (Details)
Note 14 - Net Loss Per Share Attributable to Common Stockholders- Summary of Antidilutive Securities (Details)
US Treasury Securities [Member]
Notes To Financial Statements
Notes To Financial Statements [Abstract]
At-the-market Facility [Member]
Related to at-the-market facility.
Corporate Debt Securities [Member]
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term (Year)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price (in dollars per share)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value
us-gaap_PaymentsToAcquireInvestments
Purchases of investments
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value
Grant [Member]
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)
Proceeds from maturities of investments
vxrt_RoyaltyInterestCovenantShortfallInRoyaltyPayments
Royalty Interest, Covenant, Shortfall in Royalty Payments
Represents the covenant for royalty interest relating to shortfalls in royalty payments.
vxrt_RoyaltyInterestCovenantCumulativeRemainingShortfallAmount
Royalty Interest, Covenant, Cumulative Remaining Shortfall Amount
Represents the covenant for the cumulative remaining shortfall amount in a royalty interest agreement. Calculated using the aggregate amount of remaining shortfall for each annual period.
Financial Instruments [Domain]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price (in dollars per share)
Weighted average exercise price, balance (in dollars per share)
Weighted average exercise price, balance (in dollars per share)
Weighted average exercise price, forfeited (in dollars per share)
Weighted average exercise price, canceled (in dollars per share)
Financial Instrument [Axis]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber
Balance at December 31, 2023 (in shares)
Royalty Payment, Interest, Second Period [Member]
Represents the second period of royalty repayment interest.
Weighted average exercise price, granted (in dollars per share)
Royalty Payment, Interest, First Period [Member]
Represents the first period of royalty repayment interest.
Weighted average exercise price, exercised (in dollars per share)
RA Capital Healthcare Fund 2024 [Member]
Represents the securities purchase agreement with RA Capital Healthcare Fund, L.P. in the year 2024.
Other accrued current liabilities
Total
vxrt_NetProceedsFromIssuanceOfCommonStock
Net Proceeds From Issuance of Common Stock
Represents the proceeds from issuance of common stock, net of underwriting discounts, commission and estimated offering expenses.
Accrued compensation
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsExercised
Exercised (in shares)
Lessee, Operating Leases [Text Block]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeitures
Forfeited (in shares)
Accounts payable
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number (in shares)
Number of options outstanding, beginning balance (in shares)
Number of options outstanding, balance (in shares)
Granted (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod
Number of options outstanding, canceled (in shares)
Operating lease liabilities arising from obtaining right-of-use assets
Proceeds from sale of property and equipment
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]
Accrued other expenses
Cash, Cash Equivalents and Investments [Table Text Block]
us-gaap_PolicyTextBlockAbstract
Accounting Policies
Non Cash Royalty Revenue [Member]
Non cash usage-based right to asset.
Accrued professional and consulting services
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Shares available for grant, balance (in shares)
Shares available for grant, balance (in shares)
vxrt_NoncashRevenueRelatedToSaleOfFutureRoyalties
Non-cash revenue related to sale of future royalties
Amount of non-cash accounted for as Revenue in relation to the sale of future royalties.
us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Purchase of property and equipment
Shares availabe for grant, 2019 Plan Amendment (in shares)
vxrt_GrossProceedsFromIssuanceOfCommonStock
Gross Proceeds from Issuance of Common Stock
The gross cash inflow from the additional capital contribution to the entity before deducting underwriting discounts, commission, and offering expenses.
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)
Current liabilities:
Supplemental Balance Sheet Disclosures [Text Block]
Developed Technology Rights [Member]
us-gaap_Assets
Total assets
Supplemental disclosure of non-cash investing and financing activity:
Plan Name [Axis]
Plan Name [Domain]
vxrt_ProceedsFromIssuanceOfCommonStockNet
Proceeds from Issuance of Common Stock, Net
The net cash inflow from the additional capital contribution to the entity.
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount
Common Warrants [Member]
Represents information pertaining to common warrants.
Intellectual Property [Member]
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)
Lease for Facility in South San Francisco Commenced in First Quarter of 2023 [Member]
Represents lease for facility in South San Francisco, California in first quarter of 2023.
Laboratory Equipment [Member]
Property, plant, and equipment classified as laboratory equipment.
Schedule of Property, Plant, and Equipment, Useful Life [Table Text Block]
Tabular disclosure of the useful life of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale, which acts as the basis for calculation of depreciation.
Finite-Lived Intangible Assets by Major Class [Axis]
Share-Based Payment Arrangement [Text Block]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]
Future Grants of Equity Awards [Member]
Represents future grants of equity awards.
The 2024 Inducement Award Plan [Member]
Relating to the 2024 Inducement Award Plan.
Lease for Facility in South San Francisco, California [Member]
Represents the lease for a facility in South San Francisco, California.
Department of Health and Human Services, ASPR [Member]
Relating to Department of Health and Human Services, Office of the Administration for Strategic Preparedness and Response.
The 2019 Plan [Member]
Represents information pertaining to the 2019 Equity Incentive Plan.
Award Type [Domain]
us-gaap_BusinessCombinationSeparatelyRecognizedTransactionsAdditionalDisclosuresAcquisitionCostExpensed
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed
Award Type [Axis]
Net loss
Net loss
Net loss
us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Less: accumulated amortization
us-gaap_FiniteLivedIntangibleAssetsNet
Total
Intangible assets, net
Intangible assets, net
Schedule of Common Stock Reserved for Issuance [Table Text Block]
Tabular disclosure of common stock reserved for issuance.
Restricted Stock Units (RSUs) [Member]
Intangible assets, gross
Share-Based Payment Arrangement, Option [Member]
HealthCare Royalty Partners III, L.P. [Member]
Represents the legal entity, HealthCare Royalty III, L.P.
Warrant [Member]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]
Antidilutive Securities [Axis]
Antidilutive Securities, Name [Domain]
Accrued clinical and manufacturing expenses
Amount of accrued clinical and manufacturing expenses due within one year.
Revenue [Text Block]
The entire disclosure for revenues at the end of the reporting period, and description and amounts of significant changes that occurred during the reporting period.
Business Combination Disclosure [Text Block]
Commitments and Contingencies Disclosure [Text Block]
us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
Less: accumulated depreciation
Property and equipment, net
Property and equipment, net
Goodwill
Goodwill, Ending Balance
vxrt_RoyaltyPercentage
Royalty Percentage
Royalty percentage received on net sales.
vxrt_OperatingLossCarryforwardsSubjectToExpiration
Operating Loss Carryforwards, Subject to Expiration
The amount of operating loss carryforwards subject to expiration.
Issuance of common stock upon exercise of common stock warrants
Represents the number of stock issued during the period upon the exercise of common stock warrants.
vxrt_OperatingLossCarryforwardCarriedForwardIndefinitely
Operating Loss Carryforward, Carried Forward Indefinitely
The amount of operating loss carryforward carried forward indefinitely.
Property and equipment, gross
Issuance of common stock upon exercise of common stock warrants (in shares)
Represents the number of shares of stock issued during the period upon the exercise of common stock warrants.
us-gaap_Dividends
Dividends, Total
vxrt_RoyaltyWithholdingTax
Royalty Withholding Tax
Percentage of tax withheld from royalty income.
Daiichi Sankyo [Member]
This item represents transactions between the Company and Daiichi Sankyo.
Cash flows from investing activities:
Estimated Fair Value
Corporate securities
Earnings Per Share [Text Block]
Provision for income taxes
Income Tax Expense (Benefit)
Provision for income taxes
Accrued liabilities
us-gaap_IncreaseDecreaseInAccountsPayable
Accounts payable
Lease liability
vxrt_DeferredTaxAssetsLeaseLiabilities
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from lease liabilities.
Daiichi Sankyo Collaberation and License Agreement [Member]
Royalty revenue from the sale of Inavir in Japan, pursuant to a collaboration and license agreement that Aviragen entered into with Daiichi Sankyo Company, Limited ("Daiichi Sankyo") in 2009.
Debt Instrument, Redemption, Period [Axis]
Debt Instrument, Redemption, Period [Domain]
Capitalized research and development
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from capitalized research and development.
us-gaap_OperatingExpenses
Total operating expenses
us-gaap_DefinedContributionPlanCostRecognized
Defined Contribution Plan, Cost
Liabilities Related to Sale of Future Royalties [Text Block]
The entire disclosure for the liabilities related to the sale of future royalties per the royalty interest acquisition agreement.
us-gaap_DefinedContributionPlanAdministrativeExpenses
Defined Contribution Plan, Administrative Expense
Restricted cash
Restricted Cash, Total
General and administrative
vxrt_FinitelivedIntangibleAssetRemainingLife
Finite-Lived Intangible Asset, Remaining Life (Year)
The remaining life of finite-lived intangible assets.
us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay
vxrt_RoyaltyInterestAdditionalRoyaltiesDueEachYear
Royalty Interest, Additional Royalties Due Each Year
Amount of additional royalties due each year.
vxrt_RoyaltyInterestPercentageOfAdditionalRoyaltiesDueEachYear
Royalty Interest, Percentage of Additional Royalties Due Each Year
Percentage of additional royalties due each year.
Cash and cash equivalents
Royalty [Member]
HCRP [Member]
HealthCare Royalty Partners are purchasers of royalty rights.
vxrt_DebtNoncashRoyaltyRevenuePaid
Non-cash royalty revenue paid to HCRP
The 2023 Shelf Registration [Member]
Related to the 2023 shelf registration.
Non-cash interest expense recognized
Amount of non-cash interest expense recognized in relation to the sale of future royalties.
us-gaap_AllocatedShareBasedCompensationExpense
Share-Based Payment Arrangement, Expense
Registered Direct Offering [Member]
Represents the registered direct offering.
vxrt_OpenMarketSaleAgreementMaximumAggregateOfferingPrice
Open Market Sale Agreement, Maximum Aggregate Offering Price
The maximum aggregate offering price pursuant to the open market sale agreement.
vxrt_LiabilityRelatedToSaleOfFutureRoyalties
Total liability related to sale of future royalties, start of year
Total liability related to sale of future royalties, end of year
Amount of liability associated with the sale of future royalties.
vxrt_LesseeOperatingLeaseNumberOfLeases
Lessee, Operating Lease, Number of Right-of-Use Leases
Number of right-of-use operating leases.
Amendment Flag
Comprehensive loss:
us-gaap_ComprehensiveIncomeNetOfTax
Comprehensive loss
City Area Code
vxrt_OpenMarketSaleAgreementSalesCommissionPercentage
Open Market Sale Agreement, Sales Commission, Percentage
The percentage of sales commission pursuant to the open market sale agreement.
Use of Estimates, Policy [Policy Text Block]
New Accounting Pronouncements, Policy [Policy Text Block]
us-gaap_TreasuryStockSharesAcquired
Repurchase of common stock to satisfy tax withholding (in shares)
us-gaap_SharesOutstanding
Balances (in shares)
Balances (in shares)
Common stock, shares outstanding (in shares)
Preferred stock, shares outstanding (in shares)
Preferred Stock, Shares Outstanding, Ending Balance (in shares)
Current Fiscal Year End Date
Variable lease cost
us-gaap_LeaseCost
Total operating lease cost
us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets
Prepaid expenses and other assets
us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent
Operating Lease, Weighted Average Discount Rate, Percent
us-gaap_InterestReceivable
Interest Receivable
Document Fiscal Period Focus
Operating lease cost
Document Fiscal Year Focus
Consolidation, Policy [Policy Text Block]
Short-term lease cost
Lease, Cost [Table Text Block]
Document Period End Date
us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1
Operating Lease, Weighted Average Remaining Lease Term (Year)
Entity File Number
Entity Emerging Growth Company
Document Type
Entity Small Business
Entity Shell Company
Document Information [Line Items]
Document Information [Table]
Entity Public Float
us-gaap_SeveranceCosts1
Severance Costs
Entity Filer Category
Entity Current Reporting Status
Entity Voluntary Filers
Entity Well-known Seasoned Issuer
Investments and Cash
Impairment of intangible assets
us-gaap_GoodwillImpairmentLoss
Goodwill, Impairment Loss
ATM Program [Member]
Represents the at-the-market facility.
us-gaap_ConcentrationRiskPercentage1
Concentration Risk, Percentage
us-gaap_IncreaseDecreaseInAccountsReceivable
Accounts receivable
Stock-based compensation
Entity Tax Identification Number
Entity Central Index Key
Depreciation and amortization
Entity Registrant Name
Entity [Domain]
Customer Concentration Risk [Member]
Legal Entity [Axis]
Entity Address, Address Line One
Offering costs
Investments and Cash, Fair Value Disclosure
Represents the fair value amount of investments and cash.
us-gaap_AmortizationOfIntangibleAssets
Amortization of Intangible Assets
ecd_NonRule10b51ArrTrmntdFlag
Non-Rule 10b5-1 Arrangement Terminated [Flag]
us-gaap_TreasuryStockValueAcquiredCostMethod
Repurchase of common stock to satisfy tax withholding
Entity Address, City or Town
ecd_Rule10b51ArrTrmntdFlag
Rule 10b5-1 Arrangement Terminated [Flag]
ecd_Rule10b51ArrAdoptedFlag
Rule 10b5-1 Arrangement Adopted [Flag]
Entity Address, Postal Zip Code
us-gaap_TreasuryStockCommonValue
Treasury Stock at cost, 507,020 shares and none as of December 31, 2023 and 2022, respectively
Entity Address, State or Province
Concentration Risk Type [Axis]
ecd_NonRule10b51ArrAdoptedFlag
Non-Rule 10b5-1 Arrangement Adopted [Flag]
us-gaap_AllowanceForDoubtfulAccountsReceivable
Accounts Receivable, Allowance for Credit Loss, Ending Balance
Concentration Risk Type [Domain]
Material Terms of Trading Arrangement [Text Block]
Entity Common Stock, Shares Outstanding
Accounts Receivable [Member]
Trading Symbol
Concentration Risk Benchmark [Axis]
Concentration Risk Benchmark [Domain]
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]
Issuance of common stock under ESPP (in shares)
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares)
Local Phone Number
Issuance of common stock upon exercise of options (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period (in shares)
Number of options outstanding, exercised (in shares)
us-gaap_GainLossOnDispositionOfAssets
Loss on disposal of property and equipment
us-gaap_TableTextBlock
Notes Tables
Issuance of common stock under ESPP
Release of common stock for vested restricted stock units (in shares)
Issuance of common stock upon exercise of options
Release of common stock for vested restricted stock units
Accrued Clinical And Manufacturing Expenses Policy [Policy Text Block]
Disclosure of accounting policy for inclusion of significant items in the accrued clinical and manufacturing expense report caption.
Number of options outstanding, granted (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod
Number of options outstanding, forfeited (in shares)
Collaborative Arrangement and Arrangement Other than Collaborative [Domain]
Issuance of common stock (in shares)
Stock Issued During Period, Shares, New Issues (in shares)
us-gaap_LiabilitiesAndStockholdersEquity
Total liabilities and stockholders’ equity
Issuance of common stock
Accumulated deficit
Research and development
Accumulated other comprehensive loss
Right of Use for Office and Manufacturing Facilities with Initial Terms Exceeding One Year [Member]
Represents information regarding right of use for office and manufacturing facilities with initial terms exceeding one year.
Money Market Funds [Member]
Cash and Cash Equivalents [Axis]
Cash and Cash Equivalents [Domain]
Cash [Member]
Change in operating assets and liabilities:
us-gaap_DisclosureTextBlockAbstract
Notes to Financial Statements
Subsequent Event [Member]
Operating lease liability, net of current portion
Operating lease liability, net of current portion
Gain on remeasurement of future royalty liability
The amount of gain recorded from the re-measurement of future royalty liability.
us-gaap_OperatingLeaseLiability
Present value of future minimum payments
Subsequent Event Type [Axis]
Current portion of operating lease liability
Current portion of operating lease liability
Subsequent Event Type [Domain]
Retirement Benefits [Text Block]
Subsequent Events [Text Block]
Right-of-use assets, net
Operating Lease, Right-of-Use Asset
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Undiscounted total
us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount
Less: imputed interest
us-gaap_DeferredIncomeTaxExpenseBenefit
Total Deferred
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive
Thereafter
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree
2026
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour
2027
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive
2028
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive
Thereafter
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo
2025
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree
2026
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour
2027
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths
2024
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive
2028
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo
2025
vxrt_LesseeOperatingLeaseNumberOfRenewalOption
Lessee, Operating Lease, Number of Renewal Option
Represents number of renewal option for operating lease.
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]
Facility in Burlingame, California [Member]
Related to facility in Burlingame, California.
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths
2024
Foreign Currency Transactions and Translations Policy [Policy Text Block]
Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block]
Other long-term assets
us-gaap_ShareBasedCompensation
Stock-based compensation
Lessee, Leases [Policy Text Block]
us-gaap_FiniteLivedIntangibleAssetUsefulLife
Finite-Lived Intangible Asset, Useful Life (Year)
Earnings Per Share, Policy [Policy Text Block]
Acquisition of Kindred BioSciences [Member]
Represents acquisition of Kindred BioSciences.
Operating expenses:
Total assets
Schedule of Finite-Lived Intangible Assets [Table Text Block]
us-gaap_LesseeOperatingLeaseRenewalTerm
Lessee, Operating Lease, Renewal Term (Year)
Warrants Expiring February 2025 [Member]
Represents information related to warrants expiring February 2025.
Research and Development Expense, Policy [Policy Text Block]
Warrants Expiring March 2025 [Member]
Represents information related to warrants expiring March 2025.
us-gaap_Depreciation
Depreciation, Total
vxrt_WarrantExercisePriceToBeEntitledToReceiveCashConsiderationFundamentalTransaction
Warrant Exercise Price to be Entitled to Receive Cash Consideration, Fundamental Transaction (in dollars per share)
The exercise price per share or per unit of warrants necessary to be entitled to receive cash consideration equal to Black-Scholes valuation, as defined in the warrant, in the event of a Fundamental Transaction (a transfer of ownership of the Company as defined in the warrant)
us-gaap_FinancialLiabilitiesFairValueDisclosure
Financial Liabilities Fair Value Disclosure, Total
us-gaap_SharesIssuedPricePerShare
Shares Issued, Price Per Share (in dollars per share)
us-gaap_AssetsCurrent
Total current assets
Money market funds, Fair Value
Share-Based Payment Arrangement [Policy Text Block]
Equity [Text Block]
Investments, Fair Value Disclosure
Treasury Stock, Common, Shares (in shares)
us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill
Impairment of Intangible Assets (Excluding Goodwill), Total
Interest income
Common Stock: $0.0001 par value; 250,000,000 shares authorized as of December 31, 2023 and 2022; 153,959,853 shares issued and 153,452,833 shares outstanding as of December 31, 2023 and 134,199,429 shares issued and outstanding as of December 31, 2022
Measurement Frequency [Axis]
Adjustments to reconcile net loss to net cash used in operating activities:
Acquisition of property and equipment included in accounts payable and accrued expenses
Measurement Frequency [Domain]
Fair Value, Recurring [Member]
Common stock, shares authorized (in shares)
Common Stock, Shares Authorized (in shares)
us-gaap_TangibleAssetImpairmentCharges
Tangible Asset Impairment Charges, Total
Common stock, shares issued (in shares)
Common stock, par value (in dollars per share)
Common Stock, Par or Stated Value Per Share (in dollars per share)
us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount
Common stock reserved for issuance (in shares)
Common Stock, Capital Shares Reserved for Future Issuance (in shares)
us-gaap_DeferredTaxAssetsValuationAllowance
Valuation allowance
Statistical Measurement [Domain]
Maximum [Member]
Minimum [Member]
Product and Service [Axis]
us-gaap_PaymentsForLegalSettlements
Payments for Legal Settlements
Product and Service [Domain]
us-gaap_DeferredTaxAssetsNet
Deferred tax assets net of valuation allowance
Statistical Measurement [Axis]
Litigation Case [Axis]
Litigation Case [Domain]
Preferred Stock: $0.0001 par value; 5,000,000 shares authorized; none issued and outstanding as of December 31, 2023 or 2022
Preferred stock, shares issued (in shares)
Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block]
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]
Accruals, reserves and other
us-gaap_DeferredTaxAssetsOther
Property, Plant and Equipment [Table Text Block]
us-gaap_DeferredTaxAssetsGross
Total deferred tax assets
Preferred stock, shares authorized (in shares)
Preferred Stock, Shares Authorized (in shares)
us-gaap_DeferredIncomeTaxLiabilities
Total deferred tax liabilities
Preferred stock, par value (in dollars per share)
Preferred Stock, Par or Stated Value Per Share (in dollars per share)
us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax
Revenue from Contract with Customer, Including Assessed Tax
Fair Value, Inputs, Level 3 [Member]
Other expense, net
Fair Value Hierarchy and NAV [Domain]
Customer [Axis]
Customer [Domain]
Fair Value, Inputs, Level 1 [Member]
Fair Value, Inputs, Level 2 [Member]
Fair Value Hierarchy and NAV [Axis]
First Set of Warrants Expiring September 2024 [Member]
Represents information pertaining to a first set of warrants expiring September 2024.
Laboratory equipment (in years) (Year)
us-gaap_IncreaseDecreaseInDeferredRevenue
Deferred grant revenue
Construction in Progress [Member]
Cash flows from operating activities:
Revenue [Policy Text Block]
Statement [Line Items]
us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent
Accounts Receivable, Allowance for Credit Loss, Current
Accounts receivable
Accounts Receivable, after Allowance for Credit Loss, Current
us-gaap_CashCashEquivalentsAndShortTermInvestments
Cash, Cash Equivalents, and Short-Term Investments
Short-term investments
Corporate securities
Additional paid-in capital
AOCI Attributable to Parent [Member]
Leasehold Improvements [Member]
Property, Plant and Equipment, Policy [Policy Text Block]
Long-Lived Tangible Asset [Axis]
Long-Lived Tangible Asset [Domain]
Research and development tax credits
Current assets:
Fair Value Disclosures [Text Block]
Cash, cash equivalents and restricted cash
Cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows
Cash, cash equivalents and restricted cash at beginning of the period
Cash, cash equivalents and restricted cash at end of the period
Net operating loss carryforwards
us-gaap_InvestmentIncomeNetAmortizationOfDiscountAndPremium
Amortization of discount on investments, net
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect
Net decrease in cash, cash equivalents and restricted cash
us-gaap_Liabilities
Total liabilities
us-gaap_NetCashProvidedByUsedInFinancingActivities
Net cash provided by financing activities
Commitments and contingencies (Note 9)
Sale of Stock [Axis]
Sale of Stock [Domain]
us-gaap_OperatingIncomeLoss
Operating loss
us-gaap_NetCashProvidedByUsedInOperatingActivities
Net cash used in operating activities
Other income (expense):
Prepaid expenses and other current assets
us-gaap_DeferredTaxLiabilities
Net deferred tax assets
us-gaap_NetCashProvidedByUsedInInvestingActivities
Net cash provided by (used in) investing activities
Second Set of Warrants Expiring April 2024 [Member]
Represents information pertaining to a second set of warrants expiring in April 2024.
Counterparty Name [Axis]
First Set of Warrants Expiring April 2024 [Member]
Represents information pertaining to a first set of warrants expiring in April 2024.
Counterparty Name [Domain]
Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]
Warrants Expiring March 2024 [Member]
Represents information pertaining to warrants expiring in March 2024.
Stockholders’ equity:
us-gaap_DeferredTaxLiabilitiesLeasingArrangements
Right-of-use assets
The 2022 ESPP [Member]
Represents the 2022 Employee Stock Purchase Plan.
vxrt_LesseeShortTermLeaseNumberOfLeases
Lessee, Short-term Lease, Number of Leases
The number of short-term leases of the lessee.
vxrt_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesAvailableForGrantDecreaseFromGrants
Shares available for grant, granted (in shares)
Represents the decrease in the shares available for grant attributable to shares granted during the period.
Shares available for grant, canceled (in shares)
Represents the change in the shares available for grant attributable to shares canceled during the period under the plan.
Investment, Policy [Policy Text Block]
Shares available for grant, forfeited (in shares)
Represents the change in the shares available for grant attributable to shares forfeited during the period under the plan.
Concentration Risk, Credit Risk, Policy [Policy Text Block]
us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation
Shares acquired to settle employee tax withholding liabilities
Grant Milestone Completion [Member]
Represents the completion of milestones under grants.
us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment
Depreciation on property and equipment
Employee Stock Purchase Plan [Member]
Represents employee stock purchase plan.
us-gaap_DeferredTaxLiabilitiesOtherFiniteLivedAssets
Intangible assets
Proceeds from issuance of common stock under the employee stock purchase plan
Proceeds from Stock Plans
Scenario [Domain]
Forecast [Member]
Proceeds from issuance of common stock upon exercise of warrants
us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense, Total
Retained Earnings [Member]
Proceeds from issuance of common stock upon exercise of stock options
Proceeds from Stock Options Exercised
Net proceeds from issuance of common stock
Proceeds from Issuance of Common Stock
us-gaap_CurrentStateAndLocalTaxExpenseBenefit
State
us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit
State
Scenario [Axis]
Treasury Stock, Common [Member]
us-gaap_CurrentForeignTaxExpenseBenefit
Foreign
us-gaap_DeferredForeignIncomeTaxExpenseBenefit
Foreign
Additional Paid-in Capital [Member]
us-gaap_CurrentFederalTaxExpenseBenefit
Federal
Common Stock [Member]
Himmelberg V. Vaxart, Inc. et al. [Member]
Represents the Himmelberg V. Vaxart, Inc. et al.
us-gaap_DeferredFederalIncomeTaxExpenseBenefit
Federal
Deferred:
Equity Components [Axis]
Equity Component [Domain]
Current:
us-gaap_CurrentIncomeTaxExpenseBenefit
Total Current
Securities into which warrants are convertible (in dollars per share)
Class of Warrant or Right [Axis]
Class of Warrant or Right [Domain]
vxrt_ReductionInWorkforcePercentage
Reduction in Workforce, Percentage
Amount of reduction in workforce as percentage.
Royalty Arrangement [Member]
Securities into which warrants are convertible (in shares)
Deferred Revenue Arrangement Type [Axis]
us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Loss before income taxes
Deferred Revenue [Domain]
National Tax Agency, Japan [Member]
Deferred grant revenue
Deferred Revenue, Current, Total
ICFR Auditor Attestation Flag
Deferred Revenue, by Arrangement, Disclosure [Table Text Block]
State and Local Jurisdiction [Member]
Income Tax Authority, Name [Axis]
Income Tax Authority, Name [Domain]
Income Tax Authority [Axis]
Income Tax Authority [Domain]
Domestic Tax Authority [Member]
Foreign Tax Authority [Member]
Office Equipment [Member]
vxrt_GainLossOnMerger
Gain on remeasurement of future royalty liability
Non-cash adjustment for (gain) loss on merger.
Document Annual Report
Cash and Cash Equivalents, Policy [Policy Text Block]
Receivable [Policy Text Block]
Entity Incorporation, State or Country Code
us-gaap_UnrecognizedTaxBenefits
Unrecognized Tax Benefits, Ending Balance
Beginning Balance
Ending Balance
General and Administrative Expense [Member]
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]
us-gaap_OpenTaxYear
Open Tax Year
Document Transition Report
Document Financial Statement Error Correction [Flag]
Basis of Accounting, Policy [Policy Text Block]
Entity Interactive Data Current
Security Exchange Name
us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions
Additions based on tax positions related to the current year
Title of 12(b) Security
Research and Development Expense [Member]
Current portion of liability related to sale of future royalties
vxrt_LiabilityRelatedToSaleOfFutureRoyaltiesCurrent
Current portion
Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to the selling costs of future royalties. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).
Income Statement Location [Axis]
Liability related to sale of future royalties, net of current portion
Long-term portion
Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to the selling costs of future royalties. Used to reflect the noncurrent portion of the liabilities (due after one year or beyond the normal operating cycle, if longer).
Income Statement Location [Domain]
Collaborative Arrangement and Arrangement Other than Collaborative [Axis]
Non-cash interest expense related to sale of future royalties
Non-cash interest expense related to sale of future royalties
Amount of non-cash accounted for as interest expense on liability in relation to the sale of future royalties.
Sale of future royalties
vxrt_DeferredTaxAssetsSaleOfFutureRoyaltyRights
Amount before allowance of valuation allowances of deferred tax asset attributable to deductible temporary differences from the sale of future royalty rights.
Auditor Name
Auditor Firm ID
vxrt_ProceedsFromSaleOfFutureRoyaltiesNet
Proceeds from Sale of Future Royalties, Net
The cash inflow from the sales of future royalties net pf deferred financing costs.
Auditor Location
us-gaap_TaxCreditCarryforwardAmount
Tax Credit Carryforward, Amount
us-gaap_SharePrice
Share Price (in dollars per share)
Research Tax Credit Carryforward [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)
us-gaap_PurchaseObligation
Purchase Obligation
Tax Credit Carryforward [Axis]
Tax Credit Carryforward, Name [Domain]
us-gaap_OperatingLossCarryforwards
Operating Loss Carryforwards
Statement [Table]
Statement of Financial Position [Abstract]
Shares used to compute net loss per share, basic and diluted (in shares)
us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments
Other
us-gaap_EffectiveIncomeTaxRateContinuingOperations
Provision for income taxes
Business Acquisition [Axis]
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)
Business Acquisition, Acquiree [Domain]
us-gaap_EffectiveIncomeTaxRateReconciliationPriorYearIncomeTaxes
Prior year true-up
us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance
Change in valuation allowance
Statement of Cash Flows [Abstract]
Statement of Stockholders' Equity [Abstract]
Lease Contractual Term [Domain]
Lease Contractual Term [Axis]
Income Statement [Abstract]
Schedule of Accrued Liabilities [Table Text Block]
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense
Permanently non-deductible items
June 2023 Offering [Member]
Represents June 2023 offering.
September 2021 ATM [Member]
Represents September 2021 ATM offering.
Tax credits
us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes
State taxes (net of federal benefit)
us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential
Foreign rate differential
Fair Value, Assets Measured on Recurring Basis [Table Text Block]
Cash flows from financing activities:
U.S. federal taxes at statutory rate
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent
Other long-term liabilities
September 2021 Lease for Facility in South San Francisco [Member]
Related to September 2021 lease for facility in South San Francisco.
Options and RSU [Member]
Represents options and RSUs.
us-gaap_StockholdersEquity
Total stockholders’ equity
Balances
Balances
Class of Stock [Axis]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Gross Unrealized Loss
Corporate securities
Australian Taxation Office [Member]
vxrt_CommonStockIncreaseInSharesAuthorized
Common Stock, Increase in Shares Authorized (in shares)
The number of increase in shares authorized of common stock.
ESPP [Member]
Related to ESPP.
Amortized Cost
Corporate securities
Business combination, property and equipment acquired
us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment