Amount of lessee's right to use underlying asset under operating lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-1

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Weighted average discount rate for operating lease calculated at point in time.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 53
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 53
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479589/842-20-55-53

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Period Type:	instant

- Definition

Number of right-of-use operating leases.

+ References

No definition available.

+ Details

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Namespace Prefix:	vxrt_
Data Type:	xbrli:integerItemType
Balance Type:	na
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- Details

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Namespace Prefix:
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Balance Type:
Period Type:

- Details

Name:	us-gaap_LeaseContractualTermAxis=vxrt_LeaseForFacilityInSouthSanFranciscoCommencedInThirdQuarterOf2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

Note 7 - Leases (Details Textual) $ in Thousands	Sep. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2021 USD ($)
Operating Lease, Right-of-Use Asset	$ 21,536	$ 24,840
Operating Lease, Weighted Average Discount Rate, Percent	9.80%
Operating Lease, Weighted Average Remaining Lease Term (Year)	4 years 4 months 24 days
Right of Use for Office and Manufacturing Facilities with Initial Terms Exceeding One Year [Member]
Lessee, Operating Lease, Number of Right-of-Use Leases	6
Lease for Facility in South San Francisco Commenced in Third Quarter of 2022 [Member]
Operating Lease, Right-of-Use Asset			$ 15,000
Lease for Facility in South San Francisco Commenced in First Quarter of 2023 [Member]
Operating Lease, Right-of-Use Asset			$ 3,100