Document And Entity Information
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount
Statistical Measurement [Axis]
Note To Financial Statement Details Textual
Significant Accounting Policies
Provision for income taxes
Income Tax Expense (Benefit)
Note 3 - Fair Value of Financial Instruments
Cost-plus-fixed-fee [Member]
Related to cost-plus-fixed-fee.
ecd_NonRule10b51ArrTrmntdFlag
Non-Rule 10b5-1 Arrangement Terminated [Flag]
Note 4 - Balance Sheet Components
ecd_NonRule10b51ArrAdoptedFlag
Non-Rule 10b5-1 Arrangement Adopted [Flag]
Note 6 - Liabilities Related to Sale of Future Royalties
Trading Arrangements, by Individual [Table]
Note 7 - Leases
Firm Fixed-price Milestone [Member]
Related to firm fixed-price milestone.
Material Terms of Trading Arrangement [Text Block]
Note 9 - Stockholders' Equity
Note 10 - Equity Incentive Plans
Note 11 - Net Income (Loss) Per Share Attributable to Common Stockholders
Financial Instrument [Axis]
Note 12 - Segment Reporting
Note 3 - Fair Value of Financial Instruments - Financial Assets Measured on a Recurring Basis (Details)
Note 4 - Balance Sheet Components - Cash and Cash Equivalents and Investments (Details)
us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Gross unrealized losses
Minimum [Member]
Note 4 - Balance Sheet Components - Prepaid Expenses and Other Current Assets (Details)
Gross unrealized gains
Statistical Measurement [Domain]
Note 4 - Balance Sheet Components - Property and Equipment, Net (Details)
Maximum [Member]
us-gaap_SharePrice
Share Price (in dollars per share)
Note 4 - Balance Sheet Components - Intangible Assets (Details)
Note 4 - Balance Sheet Components - Estimated Future Amortization Expense (Details)
Note 4 - Balance Sheet Components - Deferred Revenue, by Arrangement, Disclosure (Details)
Litigation Case [Domain]
Note 4 - Balance Sheet Components - Accrued Liabilities (Details)
Note 6 - Liabilities Related to Sale of Future Royalties - Deferred Revenue Activity (Details)
us-gaap_IncreaseDecreaseInAccountsReceivable
Accounts receivable
Note 7 - Leases - Lease Liabilities Payment Obligations (Details)
Note 7 - Leases - Operating Lease Expenses (Details)
Note 9 - Stockholders' Equity - Shares of Common Stock Reserved for Issuance (Details)
Note 9 - Stockholders' Equity - Summary of Warrants Outstanding (Details)
Note 10 - Equity Incentive Plans - Summary of Stock Option Transactions (Details)
Note 10 - Equity Incentive Plans - Assumptions of Options (Details)
Note 10 - Equity Incentive Plans - Total Stock-based Compensation Recognized for Options (Details)
Note 11 - Net Income (Loss) Per Share Attributable to Common Stockholders - Calculation of Basic and Diluted Net (Loss) Income Per Share (Details)
Note 11 - Net Income (Loss) Per Share Attributable to Common Stockholders - Summary of Antidilutive Securities (Details)
Note 12 - Segment Reporting - Schedule of Segment Reporting Information, by Segment (Details)
Notes To Financial Statements
Notes To Financial Statements [Abstract]
Counterparty Name [Axis]
Weighted average exercise price, forfeited (in dollars per share)
Weighted average exercise price, canceled (in dollars per share)
Weighted average exercise price, granted (in dollars per share)
Weighted average exercise price, exercised (in dollars per share)
us-gaap_Dividends
Dividends
Income Tax Jurisdiction [Domain]
Interest income
Interest income
Financial Instruments [Domain]
Litigation Case [Axis]
Leasehold Improvements [Member]
Counterparty Name [Domain]
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.
us-gaap_SharesOutstanding
Balances (in shares)
Balances (in shares)
us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions
Segment Reporting [Text Block]
Royalty Payment, Interest, Second Period [Member]
Represents the second period of royalty repayment interest.
Royalty Payment, Interest, First Period [Member]
Represents the first period of royalty repayment interest.
HHS Barda [Member]
Represents information pertaining to HHS Barda.
Award Type [Axis]
Segment Reporting [Table Text Block]
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Cost-plus-fixed-fees Arrangement Under ATI-RRPV Contract [Member]
Related to cost-plus-fixed-fees arrangement underATI-RRPV contract.
Preferred stock: $0.0001 par value; 5,000,000 shares authorized; none issued and outstanding as of March 31, 2026 and December 31, 2025
us-gaap_Liabilities
Total liabilities
Plan Name [Axis]
Plan Name [Domain]
Reimbursable Purchase Agreement Commitment to Vendor [Member]
Related to reimbursable purchase agreement commitment to vendor.
us-gaap_LiabilitiesAndStockholdersEquity
Total liabilities and stockholders’ equity
Consolidation Items [Axis]
us-gaap_AllocatedShareBasedCompensationExpense
Stock-based compensation
Cash and Cash Equivalents [Axis]
Segment Reporting [Table]
Non Cash Royalty Revenue [Member]
Non cash usage-based right to asset.
us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets
Prepaid expenses and other assets
Internal Research and Development Costs [Member]
Represents information pertaining to the internal research and development costs.
Process Development Program [Member]
Represents information pertaining to the process development program.
us-gaap_ShareBasedCompensation
Stock-based compensation
Subsequent Event [Member]
Covid-19 Program [Member]
Represents information pertaining to the Covid-19 program.
Norovirus Program [Member]
Represents information pertaining to the Norovirus Program.
Consolidation Items [Domain]
Preclinical Research [Member]
Represents information pertaining to preclinical research.
Other Programs [Member]
Represents information pertaining to other programs.
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.
Lessee, Lease, Description [Table]
Share-Based Payment Arrangement [Text Block]
Lease Contractual Term [Axis]
Lease Contractual Term [Domain]
Change in operating assets and liabilities:
us-gaap_IncreaseDecreaseInAccountsPayable
Accounts payable
Preferred stock, shares issued (in shares)
Preferred stock, shares outstanding (in shares)
Preferred Stock, Shares Outstanding, Ending Balance (in shares)
Preferred stock, shares authorized (in shares)
Preferred Stock, Shares Authorized (in shares)
Preferred stock, par value (in dollars per share)
Preferred Stock, Par or Stated Value Per Share (in dollars per share)
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect
Net increase (decrease) in cash and cash equivalents
Cash and cash equivalents
vxrt_ContractWithCustomerLiabilityAmountCollectedOrInvoiced
Amounts collected or invoiced
The amount of contract with customer liabilities collected or invoiced.
Money market funds, Fair Value
Common Warrants [Member]
Represents information pertaining to common warrants.
New Accounting Pronouncements, Policy [Policy Text Block]
Laboratory Equipment [Member]
Property, plant, and equipment classified as laboratory equipment.
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations
Cash and cash equivalents at beginning of the period
Cash and cash equivalents at end of the period
Concentration Risk, Credit Risk, Policy [Policy Text Block]
Antidilutive Securities, Name [Domain]
Comprehensive income (loss):
Statement [Table]
Prepaid insurance
us-gaap_PrepaidInsurance
us-gaap_PrepaidRoyalties
Prepaid Royalties
The 2024 Inducement Award Plan [Member]
Relating to the 2024 Inducement Award Plan.
Income Tax Authority, Name [Axis]
Income Tax Authority, Name [Domain]
Prepaid clinical services, long-term
Prepaid Expense Other, Noncurrent
The 2019 Plan [Member]
Represents information pertaining to the 2019 Equity Incentive Plan.
National Tax Agency, Japan [Member]
Investments, Fair Value Disclosure
Intellectual Property [Member]
Prepaid rent
us-gaap_PrepaidRent
Clinical Research Organization [Member]
Legal entity of party involved in collaborative agreement.
Schedule of Common Stock Reserved for Issuance [Table Text Block]
Tabular disclosure of common stock reserved for issuance.
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
Balance, Weighted average grant date fair value (in dollars per share)
Balance, Weighted average grant date fair value (in dollars per share)
Granted, Weighted average grant date fair value (in dollars per share)
HealthCare Royalty Partners III, L.P. [Member]
Represents the legal entity, HealthCare Royalty III, L.P.
Product and Service [Domain]
Product and Service [Axis]
Accrued clinical and manufacturing expenses
Amount of accrued clinical and manufacturing expenses due within one year.
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Undiscounted total
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.
vxrt_RoyaltyPercentage
Royalty Percentage
Royalty percentage received on net sales.
us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent
Operating Lease, Weighted Average Discount Rate, Percent
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)
BARDA [Member]
This item represents contractual agreements with the U.S. Office of Biomedical Advanced Research and Development Authority ("BARDA").
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths
2027
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod
Number of options outstanding, forfeited (in shares)
us-gaap_AccountsPayableCurrentAndNoncurrent
Accounts Payable
Commercial Paper [Member]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod
Number of options outstanding, canceled (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Shares available for grant, balance (in shares)
Shares available for grant, balance (in shares)
us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear
2026 (nine months remaining)
vxrt_RoyaltyWithholdingTax
Royalty Withholding Tax
Percentage of tax withheld from royalty income.
Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block]
Measurement Frequency [Axis]
vxrt_LicenseAgreementTotalTransactionPrice
License Agreement, Total Transaction Price
The total transaction price for the license agreement.
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)
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree
2029
vxrt_LicenseAgreementConsideration
License Agreement, Consideration
The amount of consideration for the license agreement.
Commitments and Contingencies Disclosure [Text Block]
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)
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo
2028
Nature of Expense [Axis]
Statement [Line Items]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value
Fair Value Hierarchy and NAV [Axis]
Common stock, shares issued (in shares)
Common stock, shares outstanding (in shares)
Award Type [Domain]
Risk-free interest rate
Common stock, shares authorized (in shares)
Common Stock, Shares Authorized (in shares)
Expected volatility
Dividend yield
Schedule of Accrued Liabilities [Table Text Block]
Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table]
Common stock: $0.0001 par value; 350,000,000 shares authorized as of March 31, 2026 and December 31, 2025; 242,169,130 shares issued and 241,414,053 shares outstanding as of March 31, 2026 and 240,742,681 shares issued and 240,494,594 shares outstanding as of December 31, 2025
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo
2028
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree
2029
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths
2027
Cash, Cash Equivalent, and Investment [Table Text Block]
Securities into which warrants are convertible (in dollars per share)
Accounts payable
us-gaap_PolicyTextBlockAbstract
Accounting Policies
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear
2026 (nine months remaining)
us-gaap_DisclosureTextBlockAbstract
Notes to Financial Statements
us-gaap_TableTextBlock
Notes Tables
us-gaap_ComprehensiveIncomeNetOfTax
Comprehensive income (loss)
Short-term investments
Accrued professional and consulting services
Subsequent Events [Text Block]
Concentration Risk Type [Axis]
Other accrued current liabilities
Total
Accrued compensation
Significant Accounting Policies [Text Block]
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.
us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount
Less: imputed interest
us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted-Average Remaining Contractual Term (Year)
Operating lease liability, net of current portion
Operating lease liability, net of current portion
us-gaap_OperatingLeaseLiability
Present value of future minimum payments
Other liabilities, current portion
Current portion of operating lease liability
Current portion of operating lease liability
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.
Fair Value, Assets Measured on Recurring Basis [Table Text Block]
vxrt_FinitelivedIntangibleAssetRemainingLife
Finite-Lived Intangible Asset, Remaining Life (Year)
The remaining life of finite-lived intangible assets.
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)
Expected term (in years) (Year)
Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block]
Concentration Risk Type [Domain]
Accounts Payable [Member]
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.
HCRP [Member]
HealthCare Royalty Partners are purchasers of royalty rights.
Amortized Cost
vxrt_DebtNoncashRoyaltyRevenuePaid
Non-cash royalty revenue paid to HCRP
Non-cash interest expense recognized
Amount of non-cash interest expense recognized in relation to the sale of future royalties.
March 2025 ATM with Citizens and B. Riley [Member]
Represents the at-the-market offering with Citizens and B. Riley entered in March 2025
Proceeds from sale of property and equipment
Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]
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 period
Total liability related to sale of future royalties, end of period
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.
Offsetting Assets [Table]
vxrt_EquityOfferingMaximumAmount
Equity Offering, Maximum Amount
The maximum value of the equity offering.
Intangible Asset, Finite-Lived, Class [Axis]
Loss Contingencies [Table]
Statement of Stockholders' Equity [Abstract]
vxrt_OpenMarketSaleAgreementSalesCommissionPercentage
Open Market Sale Agreement, Sales Commission, Percentage
The percentage of sales commission pursuant to the open market sale agreement.
Intangible Asset, Finite-Lived, Class [Domain]
Class of Warrant or Right [Axis]
Class of Warrant or Right [Domain]
Statement of Cash Flows [Abstract]
vxrt_LicenseAgreementStockToBePurchasedAmount
License Agreement, Stock To Be Purchased, Amount
The value of stock to be purchased under license agreement.
License Agreement and Purchase Agreement [Member]
Related to license agreement and purchase agreement.
vxrt_LicenseAgreementFeeToBeReceived
License Agreement, Fee To Be Received
The amount of fee to be received under license agreement.
Equity Components [Axis]
Unrealized loss on available-for-sale investments, net of tax
Proceeds from issuance of common stock upon exercise of stock options
Proceeds from Stock Options Exercised
Equity Component [Domain]
Offsetting Liabilities [Table]
Fair Value, Inputs, Level 2 [Member]
Fair Value, Inputs, Level 3 [Member]
Equity [Text Block]
Fair Value, Inputs, Level 1 [Member]
AOCI Attributable to Parent [Member]
Securities into which warrants are convertible (in shares)
Additional Paid-in Capital [Member]
Retained Earnings [Member]
Income Tax Jurisdiction, Foreign [Member]
Property and equipment, net
Property and equipment, net
Property and equipment, gross
Acquisition of property and equipment included in accounts payable and accrued expenses
Subsequent Event Type [Domain]
Subsequent Event [Table]
Subsequent Event Type [Axis]
Sale of Stock [Axis]
Stock-based compensation
Stockholders’ equity:
Investments and Cash, Fair Value Disclosure
Represents the fair value amount of investments and cash.
vxrt_PolicyTable
Share-Based Payment Arrangement, Option, Activity [Table Text Block]
vxrt_GovernmentContractAwardAmountInitialAwardFixedFee
Government Contract, Award Amount, Initial Award Fixed Fee
Amount of government contract initial fixed fee awarded that comprises amount received, receivable, and to be received unless condition for government contract is not met. Includes, but is not limited to, government grant, assistance, incentive, award, subsidy, and loan.
Fair Value Disclosures [Text Block]
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]
Share-Based Payment Arrangement, Option [Member]
Supplemental disclosure of non-cash investing and financing activity:
us-gaap_AccountsReceivableNet
Accounts Receivable, after Allowance for Credit Loss
Current liabilities:
us-gaap_LiabilitiesCurrent
Total current liabilities
Accounts receivable
Customer Concentration Risk [Member]
Lease, Cost [Table Text Block]
us-gaap_GainLossOnDispositionOfAssets1
Loss on sale of property and equipment
us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment
Less: accumulated depreciation
Collaboration Revenue [Member]
Represents the collaboration revenue.
Accumulated other comprehensive loss
us-gaap_PaymentsToAcquireInvestments
Purchases of investments
us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Less: accumulated amortization
Research and Development [Member]
In relation to research and development.
Other Accrued Liabilities [Member]
In relation to other accrued liabilities.
Prepaid Expenses [Member]
In relation to prepaid expenses
General and administrative
General and administrative
vxrt_LicenseAgreementTotalTransactionCosts
License Agreement, Total Transaction Costs
The total amount of transaction costs for the license agreement.
us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Income (loss) before income taxes
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.
Additional paid-in capital
vxrt_LicenseAgreementPremium
License Agreement, Premium
The premium expense for the license agreement.
Use of Estimates, Policy [Policy Text Block]
Prepaid expenses and other current assets
Prepaid expenses and other current assets
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)
us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Purchases of property and equipment
Lessee, Operating Leases [Text Block]
Current assets:
Money Market Funds [Member]
Issuance of common stock upon exercise of stock options
us-gaap_AssetsCurrent
Total current assets
Release of common stock for vested restricted stock units
us-gaap_LitigationSettlementAmountAwardedToOtherParty
Litigation Settlement, Amount Awarded to Other Party
us-gaap_StockIssuedDuringPeriodSharesNewIssues
Stock Issued During Period, Shares, New Issues (in shares)
Restricted Stock Units (RSUs) [Member]
Issuance of common stock upon exercise of stock 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)
Fair Value Measurement Inputs and Valuation Techniques [Table]
Release of common stock for vested restricted stock units (in shares)
us-gaap_Depreciation
Depreciation
us-gaap_TreasuryStockSharesAcquired
Repurchase of common stock to satisfy tax withholding (in shares)
Cash flows from operating activities:
Cash flows from investing activities:
us-gaap_NetCashProvidedByUsedInOperatingActivities
Net cash used in operating activities
Cash flows from financing activities:
us-gaap_NetCashProvidedByUsedInInvestingActivities
Net cash (used in) provided by investing activities
Intangible Asset, Finite-Lived, and Capitalized Cost, Software to be Sold, Leased, or Marketed, Estimated Amortization Expense [Table Text Block]
us-gaap_NetCashProvidedByUsedInFinancingActivities
Net cash used in financing activities
Total assets
Debt Instrument, Redemption, Period [Axis]
Debt Instrument, Redemption, Period [Domain]
Proceeds from maturities of investments
us-gaap_GoodwillImpairmentLoss
Goodwill, Impairment Loss
Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment [Member]
Developed Technology Rights [Member]
Operating Segments [Member]
Accounting Policies [Abstract]
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Table Text Block]
US Treasury Securities [Member]
Income Statement [Abstract]
us-gaap_NumberOfReportableSegments
Number of Reportable Segments
us-gaap_PurchaseObligation
Purchase Obligation
us-gaap_TreasuryStockCommonValue
Treasury stock at cost, 755,077 shares as of March 31, 2026 and 248,087 shares as of December 31, 2025
Treasury Stock, Common, Shares (in shares)
Balances (in shares)
Balances (in shares)
Treasury Stock, Common [Member]
Deferred Revenue [Domain]
Net income (loss)
Net income (loss)
Adjustments and reconciling items
Deferred Revenue Arrangement Type [Axis]
us-gaap_GovernmentAssistanceAwardAmount
Government Assistance, Award Amount
us-gaap_AmortizationOfIntangibleAssets
Intangible Asset, Finite-Lived, Amortization Expense
us-gaap_AreaOfRealEstateProperty
Area of Real Estate Property (Acre)
Share-Based Payment Arrangement [Member]
Accounting Standards Update and Change in Accounting Principle [Table]
us-gaap_TreasuryStockValueAcquiredCostMethod
Repurchase of common stock to satisfy tax withholding
Supplemental Balance Sheet Disclosures [Text Block]
Collaborative Arrangement and Arrangement Other than Collaborative [Axis]
us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss
Debt Securities, Available-for-Sale, Allowance for Credit Loss
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value
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)
The March 2025 ATM [Member]
Represents the March 2025 ATM offering.
Fair Value Hierarchy and NAV [Domain]
Measurement Frequency [Domain]
Other income (expense):
Statement of Financial Position [Abstract]
us-gaap_TangibleAssetImpairmentCharges
Tangible Asset Impairment Charges
Fair Value, Recurring [Member]
Other long-term assets
Warrants Expiring December 2026 [Member]
Represents information pertaining to warrants expiring in December 2026.
us-gaap_IncreaseDecreaseInDeferredRevenue
Deferred revenue
us-gaap_DeferredRevenue
Deferred Revenue
Warrant [Member]
Document Type
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.
Operating expenses:
Document Information [Line Items]
Document Quarterly Report
us-gaap_ConcentrationRiskPercentage1
Concentration Risk, Percentage
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.
Deferred collaboration revenue, net of current portion
Deferred Revenue, Noncurrent
us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1
Operating Lease, Weighted Average Remaining Lease Term (Year)
Document Information [Table]
Deferred revenue
Deferred Revenue, Current
Current portion
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.
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)
Antidilutive Securities [Axis]
us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment
Weighted Average Number of Shares Outstanding, Diluted, Adjustment (in shares)
Entity Interactive Data Current
Document Transition Report
Diluted (in shares)
Weighted average shares used to compute net income (loss) per share, diluted (in shares)
Employee Stock Purchase Plan [Member]
Represents employee stock purchase plan.
us-gaap_OperatingExpenses
Total operating expenses
Purchase Commitment, Excluding Long-Term Commitment [Domain]
Net income (loss) per share:
Purchase Commitment, Excluding Long-Term Commitment [Axis]
Basic (in shares)
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]
Election Payment [Member]
Relating to election payment.
Antidilutive Security, Excluded EPS Calculation [Table]
Basic (in dollars per share)
Basic (in dollars per share)
vxrt_ContractWithCustomerLiabilityRevenueRecognizedIncludingOpeningBalance
Revenue recognized
Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.
Collaborative Arrangement and Arrangement Other than Collaborative [Domain]
Office Equipment [Member]
Income Tax Jurisdiction [Axis]
Intangible assets, net
Intangible assets, net
us-gaap_FiniteLivedIntangibleAssetsNet
Total
Document Fiscal Period Focus
Customer [Domain]
Intangible assets, gross
Document Fiscal Year Focus
Depreciation and amortization
Amendment Flag
Himmelberg V. Vaxart, Inc. et al. [Member]
Represents the Himmelberg V. Vaxart, Inc. et al.
us-gaap_SubleaseIncome
Sublease income
Common Stock [Member]
us-gaap_InvestmentIncomeNetAmortizationOfDiscountAndPremium
Net accretion of discounts on investments
Goodwill
Goodwill
Document Period End Date
Long-Lived Asset, Class [Domain]
Variable lease cost
Number of options outstanding, granted (in shares)
Legal Entity [Axis]
vxrt_SharebasedCompensationArrangementBySharebasedPaymentAwardNonoptionEquityInstrumentsReleased
Number of RSUs outstanding, release (in shares)
Number of non-option equity instruments released by participants.
us-gaap_FinancialLiabilitiesFairValueDisclosure
Financial Liabilities Fair Value Disclosure, Total
Operating lease cost
Short-term lease cost
Construction in Progress [Member]
us-gaap_LeaseCost
Total lease cost
Released, Weighted average grant date fair value (in dollars per share)
Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were released.
Entity File Number
Entity Tax Identification Number
Disaggregation of Revenue [Table]
Entity [Domain]
Entity Central Index Key
Entity Registrant Name
Entity Current Reporting Status
Entity Incorporation, State or Country Code
Current Fiscal Year End Date
Unrealized loss on available-for-sale investments
Research and development
Research and Development Expense
Entity Filer Category
Entity Shell Company
Entity Emerging Growth Company
us-gaap_DebtSecuritiesAvailableForSaleGainLoss
Debt Securities, Available-for-Sale, Gain (Loss)
Entity Small Business
us-gaap_OperatingIncomeLoss
Operating income (loss)
Cash and Cash Equivalents [Domain]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
us-gaap_SegmentReportingOtherItemAmount
Other segment items(A)
us-gaap_Revenues
Revenues
Revenue:
Entity Address, State or Province
Entity Address, City or Town
Accumulated deficit
Entity Address, Address Line One
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]
City Area Code
us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation
Shares acquired to settle employee tax withholding liabilities
Local Phone Number
Government Assistance, Type [Domain]
Entity Address, Postal Zip Code
Accrued and other liabilities
Title of 12(b) Security
Unbilled receivable from government contracts
Unbilled Receivables, Current
Trading Symbol
Class of Stock [Axis]
Government Assistance, Type [Axis]
Estimated Fair Value
Revenue [Policy Text Block]
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).
Entity Common Stock, Shares Outstanding
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).
Earnings Per Share [Text Block]
Other current assets
Non-cash interest expense related to sale of future royalties
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.
vxrt_ProceedsFromSaleOfFutureRoyaltiesNet
Proceeds from Sale of Future Royalties, Net
The cash inflow from the sales of future royalties net pf deferred financing costs.
Royalty Arrangement [Member]
Prepaid clinical and manufacturing expenses
vxrt_PrepaidClinicalAndManufacturingExpenses
Amount of asset related to consideration paid in advance for clinical and manufacturing expenses.
Common stock, par value (in dollars per share)
Common Stock, Par or Stated Value Per Share (in dollars per share)
Basis of Accounting, Policy [Policy Text Block]
Other expense, net
Long-Lived Asset, Class [Axis]
Sale of Stock [Domain]
us-gaap_UnbilledContractsReceivable
Unbilled Contracts Receivable
us-gaap_Assets
Total assets
Investments and Cash
Cash and Cash Equivalents, at Carrying Value
us-gaap_CashCashEquivalentsAndShortTermInvestments
Cash, Cash Equivalents, and Short-Term Investments
Other prepaid
Cash [Member]
us-gaap_AllowanceForDoubtfulAccountsReceivable
Accounts Receivable, Allowance for Credit Loss
Common stock reserved for issuance (in shares)
Diluted (in dollars per share)
Diluted (in dollars per share)
us-gaap_ContractWithCustomerLiability
Deferred Revenue, Balance
Deferred Revenue, Balance
Customer [Axis]
The April 2026 ATM [Member]
Related to the April 2026 ATM.
Government Contract [Member]
Consolidation, Policy [Policy Text Block]
LPC ELOC Purchase Agreement [Member]
The ELOC equity purchase agreement with LPC.
LPC [Member]
Represents the company LPC.
us-gaap_InterestReceivable
Interest Receivable
Utah Avenue Lease [Member]
Represents the lease for the Utah Avenue building.
vxrt_IncreaseDecreaseInUnbilledReceivable
Unbilled receivable from government contracts
The increase (decrease) during the reporting period of the amount of revenue for work performed for which billing has not occurred, net of uncollectible accounts.
vxrt_EqupercentOfShareOwnership
EquPercent of Share Ownership
Represents the percent of shares owned.
General and Administrative [Member]
Represents the General and administrative expenses.
vxrt_PercentOfSharePriceForEquityOffering
Percent of Share Price for Equity Offering
The percent of the price per share for the equity offering.
Common Stock Outstanding [Member]
Represents common stock outstanding.
The 2024 ASPR-BARDA Contract [Member]
Represents The 2024 ASPR-BARDA Contract.
Intangible Asset, Finite-Lived [Table Text Block]
The 2024 ATI-RRPV Contract [Member]
Represents The 2024 ATI-RRPV Contract.
vxrt_GovernmentAssistanceAwardAmountInitialAward
Government Assistance, Award Amount, Initial Award
Initial amount of government assistance awarded that comprises amount received, receivable, and to be received unless condition for government assistance is not met. Includes, but is not limited to, government grant, assistance, incentive, award, subsidy, and loan.
Interim Period, Costs Not Allocable [Domain]
Royalty [Member]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber
Number of RSUs outstanding (in shares)
Number of RSUs outstanding (in shares)
Number of RSUs outstanding, granted (in shares)
Deferred Revenue, by Arrangement, Disclosure [Table Text Block]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeitures
Number of RSUs outstanding, forfeite (in shares)
us-gaap_StockholdersEquity
Total stockholders’ equity
Balances
Balances
Forfeited, Weighted average grant date fair value (in dollars per share)
Stock, Class of Stock [Table]
Concentration Risk Benchmark [Axis]
Concentration Risk Benchmark [Domain]
us-gaap_PaymentsForLegalSettlements
Payments for Legal Settlements
Right-of-use assets, net
Operating Lease, Right-of-Use Asset
Other long-term liabilities
ESPP [Member]
Related to ESPP.
ecd_Rule10b51ArrTrmntdFlag
Rule 10b5-1 Arrangement Terminated [Flag]
Property, Plant, and Equipment [Table Text Block]
ecd_Rule10b51ArrAdoptedFlag
Rule 10b5-1 Arrangement Adopted [Flag]
Commitments and contingencies (Note 8)