0001437749-23-006688 | 10-K | XBRL Viewer

Business Combination Disclosure [Text Block]

NOTE 3. Business Combination

On November 30, 2021, the Company closed its acquisition of Kindred BioSciences, Inc.’s GMP manufacturing line in Burlingame, California in exchange for $4.8 million in cash. The transaction was accounted for as a business combination and the Company incurred transaction related expenses totaling $82,000, which were recorded within general and administrative expenses in the consolidated statement of operations in the year ended December 31, 2021.

The fair value of the assets acquired in connection with the acquisition are as follows (in thousands):

Property and equipment	$	321
Goodwill		4,508

Total purchase price	$	4,829

In addition, the Company paid $671,000 in prepaid rent in connection with the modification of the pre-existing embedded lease at the Burlingame facility (see Note 8).

Goodwill, which represents the excess of the purchase price over the fair value of assets acquired, is attributable primarily to the expected cost savings of manufacturing internally, as opposed to outsourcing, and the assembled workforce. All of the goodwill is expected to be deductible for income tax purposes.

Note 13 - Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2019	Dec. 31, 2020
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	21.00%
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 23,700	$ 20,600
Unrecognized Tax Benefits, Ending Balance	4,945	2,422		$ 1,281
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense, Total	0	0
Domestic Tax Authority [Member]
Operating Loss Carryforwards	162,100	115,900
Domestic Tax Authority [Member] \| Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	6,900	3,100
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	$ 85,000	84,800
Open Tax Year	2016 2017 2018 2019 2020 2021
State and Local Jurisdiction [Member] \| Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	$ 7,000	$ 5,000
Foreign Tax Authority [Member] \| Australian Taxation Office [Member]
Operating Loss Carryforwards	$ 6,200

Note 14 - Net Loss Per Share Attributable to Common Stockholders- Summary of Antidilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	14,649,185	8,575,180
Share-Based Payment Arrangement, Option [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	13,567,390	8,206,137
Restricted Stock Units (RSUs) [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	460,975	0
Warrant [Member] \| Common Stock [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	228,725	369,043
Employee Stock Purchase Plan [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	392,095	0

Document And Entity Information - USD ($)	12 Months Ended
Document And Entity Information - USD ($)	Dec. 31, 2022	Mar. 14, 2023	Jun. 30, 2022
Document Information [Line Items]
Entity Central Index Key	0000072444
Entity Registrant Name	Vaxart, Inc.
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2022
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2022
Document Transition Report	false
Entity File Number	001-35285
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	59-1212264
Entity Address, Address Line One	170 Harbor Way, Suite 300
Entity Address, City or Town	South San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94080
City Area Code	650
Local Phone Number	550-3500
Title of 12(b) Security	Common Stock, $0.0001 par value
Trading Symbol	VXRT
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 393,574,122
Entity Common Stock, Shares Outstanding		135,561,649
Auditor Name	WithumSmith+Brown, PC
Auditor Location	San Francisco, California
Auditor Firm ID	100

Note 6 - Revenue

12 Months Ended

Dec. 31, 2022

Revenue [Text Block]

NOTE 6. Revenue

Royalty agreement

The Company generates 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. In September 2010, laninamivir octanoate was approved for sale by the Japanese Ministry of Health and Welfare for the treatment of influenza in adults and children, which Daiichi Sankyo markets as Inavir. Under the agreement, the Company currently receives a 4% royalty on net sales of Inavir in Japan. The last patent related to Inavir is set to expire in December 2029 in Japan, at which time royalty revenue will cease. The royalty revenue related to Inavir recognized in 2022 and 2021, was nil. In addition, the Company recognized non-cash royalty revenue related to sale of future royalties (see Note 7) of $107,000 and $879,000 in 2022 and 2021, respectively. Both the royalty revenue and the non-cash royalty revenue related to sale of future royalties have been subjected to a 5% withholding tax in Japan, for which $5,000 and $44,000 was included in income tax expense in the years ended December 31, 2022 and 2021, respectively.

Note 6 - Revenue (Details Textual) - USD ($)	12 Months Ended
Note 6 - Revenue (Details Textual) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Revenue from Contract with Customer, Including Assessed Tax	$ 107,000	$ 892,000
Income Tax Expense (Benefit), Total	$ 67,000	107,000
Foreign Tax Authority [Member] \| National Tax Agency, Japan [Member]
Royalty Withholding Tax	5.00%
Income Tax Expense (Benefit), Total	$ 5,000	44,000
Royalty [Member] \| Daiichi Sankyo Collaberation and License Agreement [Member]
Royalty Percentage	4.00%
Revenue from Contract with Customer, Including Assessed Tax	$ 0
Non Cash Royalty Revenue [Member]
Revenue from Contract with Customer, Including Assessed Tax	107,000	879,000
Non Cash Royalty Revenue [Member] \| Daiichi Sankyo Collaberation and License Agreement [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 107,000	$ 879,000

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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Note 2 - Summary of Significant Accounting Policies - Estimated Useful Lives (Details)	12 Months Ended
	Dec. 31, 2022
Laboratory Equipment [Member]
Laboratory equipment (in years) (Year)	5 years
Office Equipment [Member]
Laboratory equipment (in years) (Year)	3 years

Note 13 - Income Taxes

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Text Block]

NOTE 13. Income Taxes

The provision for income taxes consists of the following (in thousands):

	*Year Ended December 31,*
	*2022*		*2021*

Current:
Federal	$	—	$	—
State		3		1
Foreign		64		106

Total Current		67		107

Deferred:
Federal		—		—
State		—		—
Foreign		—		—

Total Deferred		—		—

Provision for income taxes	$	67	$	107

The components of the deferred tax assets are as follows (in thousands):

	*December 31, 2022*			*December 31, 2021*
Deferred tax assets:
Net operating loss carryforwards	$	39,822		$	30,256
Research and development tax credits		7,943			4,923
Capitalized research and development		14,260			4,016
Sale of future royalties		2,886			5,826
Lease liability		4,581			3,184
Accruals, reserves and other		5,004			3,043
Total deferred tax assets		74,496			51,248
Valuation allowance		(66,323	)		(42,589	)
Deferred tax assets net of valuation allowance		8,173			8,659
Deferred tax liabilities:
Intangible assets		(2,614	)		(5,410	)
Right-of-use assets		(5,427	)		(3,223	)
Depreciation on property and equipment		(132	)		(26	)
Total deferred tax liabilities		(8,173	)		(8,659	)

Net deferred tax assets	$	—		$	—

A reconciliation of the provision for income taxes with the expected provision for income taxes computed by applying the federal statutory income tax rate of 21% to the net loss before provision for income taxes:

	*Year Ended December 31,*
	*2022*			*2021*

U.S. federal taxes at statutory rate		21.0	%		21.0	%
State taxes (net of federal benefit)		0.1			4.0
Foreign rate differential		(0.3	)		0.3
Permanently non-deductible items		(1.5	)		0.2
Tax credits		3.0			3.4
Change in valuation allowance		(22.0	)		(29.3	)
Tax attributes write-off due to change in control		—			—
Prior year true-up		(0.2	)		0.6
Other		(0.2	)		(0.3	)

Provision for income taxes		(0.1	)%		(0.1	)%

The Company’s actual tax expense differed from the statutory federal income tax expense using a tax rate of 21% for the years ended December 31, 2022 and 2021, respectively, primarily due to foreign income taxes being taxed at different rates, nondeductible expenses, research and development tax credits, and the change in valuation allowance.

As of December 31, 2022 and 2021, the Company had net operating loss (“NOL”) carryforwards of $162.1 million and $115.9 million for federal purposes, and $85.0 million and $84.8 million for state purposes, respectively. If not utilized, these carryforwards will begin to expire in 2024 for federal, and 2028 for state purposes.

As of December 31, 2022, the Company also has accumulated tax losses of $6.2 million for Australia available for carryforward against future earnings, which under relevant tax laws do not expire but may not be available under certain circumstances.

As of December 31, 2022 and 2021, the Company had research and development tax credit carryforwards for federal purposes of $6.9 million and $3.1 million, respectively, and state research and development tax credit carryforwards of $7.0 million and $5.0 million, respectively. The federal research and development tax credit carryforwards will expire at various dates beginning in the year 2039. The state research and development tax credit carryforwards do not expire.

Beginning on January 1, 2022, the Tax Cuts and Jobs Act (“the Act”), enacted in December 2017, eliminated the option to deduct research and development expenditures in the current period and requires taxpayers to capitalize and amortize U.S.-based and non-U.S. based research and development expenditures over five and fifteen years, respectively. This legislation does not impact the Company's current tax obligations.

Sections 382 and 383 of the Internal Revenue Code provide for a limitation on the annual use of NOL and tax credit carryforwards following certain ownership changes that could limit the Company’s ability to utilize these carryforwards. The Company has completed an analysis to determine if such ownership changes have occurred and concluded it was more likely than not that there were changes in ownership. Due to the existence of full valuation allowance, limitations under Section 382 and 383 will not impact the Company’s effective tax rate. Further analyses will be performed prior to recognizing the benefits of any losses or credits in the financial statements.

The Company is required to reduce its deferred tax assets by a valuation allowance if it is more likely than not that some or all of its deferred tax assets will not be realized. Management must use judgment in assessing the potential need for a valuation allowance, which requires an evaluation of both negative and positive evidence. The weight given to the potential effect of negative and positive evidence should be commensurate with the extent to which it can be objectively verified. In determining the need for and amount of the valuation allowance, if any, the Company assesses the likelihood that it will be able to recover its deferred tax assets using historical levels of income, estimates of future income and tax planning strategies. As a result of historical cumulative losses, the Company determined that, based on all available evidence, there was substantial uncertainty as to whether it will recover recorded net deferred taxes in future periods. Accordingly, the Company recorded a valuation allowance against all of its net deferred tax assets as of December 31, 2022 and 2021. The net change in total valuation allowance was an increase of approximately $23.7 million and $20.6 million for the years ended December 31, 2022 and 2021, respectively.

The Company records unrecognized tax benefits, where appropriate, for all uncertain income tax positions. The Company recorded unrecognized tax benefits for uncertain tax positions of approximately $4.9 million and $2.4 million as of December 31, 2022 and 2021, respectively, of which none would impact the effective tax rate, if recognized, because the benefit would be offset by an increase in the valuation allowance.

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands):

	*Year Ended December 31,*
	*2022*			*2021*

Beginning Balance	$	2,422		$	1,281
Additions based on tax positions related to the current year		2,589			1,132
Increase (decreases) related to prior years’ tax positions		(66	)		9

Ending Balance	$	4,945		$	2,422

The Company’s policy is to recognize interest and penalties accrued on any unrecognized tax benefits as a component of income tax expense. During the year ended December 31, 2022 and 2021, the Company recognized no interest and penalties associated with unrecognized tax benefits. There are no tax positions for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly increase or decrease within twelve months of the reporting date.

The Company files income tax returns in the U.S, Australia, as well as with various U.S. states. The Company is subject to tax audits in all jurisdictions in which it files income tax returns. Tax audits by their very nature are often complex and can require several years to complete. There are currently no tax audits that have commenced with respect to income tax returns in any jurisdiction.

Under the tax statute of limitations applicable to the Internal Revenue Code, the Company and its U.S. subsidiary, either standalone or as part of the consolidated group, is no longer subject to U.S. federal income tax examinations by the Internal Revenue Service for tax years before tax year 2017. Under the statute of limitations applicable to most state income tax laws, the Company is no longer subject to state income tax examinations by tax authorities for tax year before 2016 in states in which it has filed income tax returns. However, because the Company is carrying forward income tax attributes, such as net operating losses and tax credits from 2004 and earlier tax years, these attributes can still be audited when utilized on returns filed in the future. The Company is subject to foreign tax examinations by tax authorities for fiscal year 2015 and forward.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

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Consolidated Balance Sheets (Parentheticals) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	250,000,000	150,000,000
Common stock, shares issued (in shares)	134,199,429	125,594,393
Common stock, shares outstanding (in shares)	134,199,429	125,594,393

Note 8 - Leases (Details Textual) $ in Millions	Dec. 31, 2022 USD ($)	Jul. 31, 2019
Lessee, Operating Lease, Expected Tenant Improvements	$ 2.3
Operating Lease, Weighted Average Discount Rate, Percent	9.80%
Operating Lease, Weighted Average Remaining Lease Term (Year)	6 years 1 month 6 days
Short-Term Lease Commitment, Amount	$ 29.4
Lessee, Finance Lease, Number of Leases	0
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
Operating Lease Arrangements for Facilities [Member]
Lessee, Short-term Lease, Number of Leases	2
Lease Agreements for Manufacturing Equipment with Initial Terms of One Year or Less [Member]
Lessee, Short-term Lease, Number of Leases	1
South San Francisco Real Estate [Member]
Lessee, Operating Lease, Renewal Term (Year)	8 years	5 years
September 2021 Lease for Facility in South San Francisco [Member]
Lessee, Operating Lease, Renewal Term (Year)	8 years
Facility in South San Francisco [Member]
Lessee, Operating Lease, Renewal Term (Year)	5 years
Facility in Burlingame, California [Member]
Lessee, Short-term Lease, Number of Leases	2
Lessee, Operating Lease, Renewal Term (Year)	30 months
Lessee, Operating Lease, Number of Renewal Option	2

Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Cash, Cash Equivalents, and Short-Term Investments, Total		$ 95,700
Net Cash Provided by (Used in) Operating Activities, Total		(94,779)	$ (59,832)
Restricted Cash, Total		2,000	0
Accounts Receivable, Allowance for Credit Loss, Ending Balance			0
Deferred Revenue, Current, Total		$ 2,000	$ 0
Developed Technology Rights [Member] \| Maximum [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	11 years 9 months		11 years 9 months
Intellectual Property [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	20 years		20 years

Note 5 - Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2022

Cash, Cash Equivalents and Investments [Table Text Block]

	*Amortized*		*Gross Unrealized*					*Estimated*		*Cash, Cash Equivalents*		*Short-Term*		*Long-Term*
	*Cost*		*Gains*		*Losses*			*Fair Value*		*and Restricted Cash*		*Investments*		*Investments*
December 31, 2022
Cash at banks	$	15,179	$	—	$	—		$	15,179	$	15,179	$	—	$	—
Money market funds		30,834		—		—			30,834		30,834		—		—
U.S. Treasury securities		41,812		—		(270	)		41,542		—		41,542		—
Commercial paper		2,488		—		—			2,488		—		2,488		—
Corporate debt securities		5,703		—		(29	)		5,674		—		5,674		—
Total	$	96,016	$	—	$	(299	)	$	95,717	$	46,013	$	49,704	$	—

	*Amortized*		*Gross Unrealized*					*Estimated*		*Cash and Cash*		*Short-Term*		*Long-Term*
	*Cost*		*Gains*		*Losses*			*Fair Value*		*Equivalents*		*Investments*		*Investments*
December 31, 2021
Cash at banks	$	72,767	$	—	$	—		$	72,767	$	72,767	$	—	$	—
Money market funds		70,978		—		—			70,978		70,978		—		—
U.S. Treasury securities		25,055		—		(58	)		24,997		—		12,022		12,975
Commercial paper		7,491		—		—			7,491		—		7,491		—
Corporate debt securities		6,480		—		(16	)		6,464		—		3,229		3,235
Total	$	182,771	$	—	$	(74	)	$	182,697	$	143,745	$	22,742	$	16,210

Property, Plant and Equipment [Table Text Block]

	*December 31, 2022*			*December 31, 2021*

Laboratory equipment	$	12,035		$	5,057
Office and computer equipment		1,078			481
Leasehold improvements		1,760			1,063
Construction in progress		3,984			1,305
Total property and equipment		18,857			7,906
Less: accumulated depreciation		(3,272	)		(1,305	)
Property and equipment, net	$	15,585		$	6,601

Schedule of Finite-Lived Intangible Assets [Table Text Block]

	*December 31, 2022*			*December 31, 2021*

Developed technology	$	5,000		$	10,600
Intellectual property		80			80
Total cost		5,080			10,680
Less: accumulated amortization		(60	)		(56	)
Intangible assets, net	$	5,020		$	10,624

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

Year Ending December 31,	Amount
2023	$	731
2024		731
2025		731
2026		731
2027		731
Thereafter		1,365
Total	$	5,020

Schedule of Accrued Liabilities [Table Text Block]

	*December 31, 2022*		*December 31, 2021*

Accrued compensation	$	3,112	$	2,786
Accrued clinical and manufacturing expenses		2,413		986
Accrued professional and consulting services		691		556
Accrued other expenses		1,868		736
Total	$	8,084	$	5,064

Note 14 - Net Loss Per Share Attributable to Common Stockholders (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Dilutive Securities, Effect on Basic Earnings Per Share, Total	$ 0

Note 12 - Benefit Plan (Details Textual) - USD ($)	12 Months Ended
Note 12 - Benefit Plan (Details Textual) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay		3.00%
Defined Contribution Plan, Cost	$ 658,000	$ 288,000
Defined Contribution Plan, Administrative Expense	$ 19,000	$ 14,000

Note 11 - Equity Incentive Plans - Total Stock-based Compensation Recognized for Options (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement, Expense	$ 13,587	$ 8,867
Research and Development Expense [Member]
Share-Based Payment Arrangement, Expense	9,183	4,304
General and Administrative Expense [Member]
Share-Based Payment Arrangement, Expense	$ 4,404	$ 4,563

Condensed Consolidated Statements of Stockholders' Equity (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Offering costs	$ 786	$ 5,752

Note 10 - Stockholders' Equity - Summary of Warrants Outstanding (Details)	Dec. 31, 2022 $ / shares shares
Securities into which warrants are convertible (in shares)	227,434
First Set of Warrants Expiring September 2024 [Member]
Securities into which warrants are convertible (in shares)	44,148
Securities into which warrants are convertible (in dollars per share) \| $ / shares	$ 1.10
First Set of Warrants Expiring April 2024 [Member]
Securities into which warrants are convertible (in shares)	26,515
Securities into which warrants are convertible (in dollars per share) \| $ / shares	$ 1.375
Second Set of Warrants Expiring April 2024 [Member]
Securities into which warrants are convertible (in shares)	29,150
Securities into which warrants are convertible (in dollars per share) \| $ / shares	$ 2.50
Warrants Expiring March 2025 [Member]
Securities into which warrants are convertible (in shares)	100,532
Securities into which warrants are convertible (in dollars per share) \| $ / shares	$ 3.125
Warrants Expiring February 2025 [Member]
Securities into which warrants are convertible (in shares)	16,175
Securities into which warrants are convertible (in dollars per share) \| $ / shares	$ 3.125
Warrants Expiring March 2024 [Member]
Securities into which warrants are convertible (in shares)	10,914
Securities into which warrants are convertible (in dollars per share) \| $ / shares	$ 22.99

Note 5 - Balance Sheet Components - Estimated Future Amortization Expense (Details) $ in Thousands	Dec. 31, 2022 USD ($)
2023	$ 731
2024	731
2025	731
2026	731
2027	731
Thereafter	1,365
Total	$ 5,020

Note 12 - Benefit Plan

12 Months Ended

Dec. 31, 2022

Retirement Benefits [Text Block]

NOTE 12. Benefit Plan

The Company provides a tax-qualified employee savings and retirement plan commonly known as a 401(k) plan (the “Plan”), which covers the Company’s eligible employees. Pursuant to the Plan, employees may elect to defer their current compensation up to the IRS annual contribution limit of $20,500 for calendar year 2022 and $19,500 for calendar year 2021. Employees age 50 or over may elect to contribute an additional $6,500 annually for 2022 and 2021.

Employees direct their contributions, which vest immediately, across a series of mutual funds. In the years ended December 31, 2022 and 2021, the Company matched employee contributions up to 3% of each employee’s eligible earnings, vesting immediately. The Company’s matching contributions totaled $658,000 and $288,000 in the years ended December 31, 2022 and 2021, respectively. The costs of administering the Plan totaled $19,000 and $14,000 in the years ended December 31, 2022 and 2021, respectively.

The entire disclosure for retirement benefits.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
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Basis of Accounting, Policy [Policy Text Block]

Note 3 - Business Combination (Details Textual)	Nov. 30, 2021 USD ($)
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed	$ 82,000
Prepaid Rent	671,000
Acquisition of Kindred BioSciences [Member]
Business Combination, Consideration Transferred, Total	$ 4,829,000

Note 10 - Stockholders' Equity - Shares of Common Stock Reserved for Issuance (Details) - shares	Dec. 31, 2022	Dec. 31, 2021
Common stock reserved for issuance (in shares)	29,635,697	16,031,282
Common Warrants [Member]
Common stock reserved for issuance (in shares)	227,434	232,434
Share-Based Payment Arrangement, Option [Member]
Common stock reserved for issuance (in shares)	14,725,261	10,216,106
Restricted Stock Units (RSUs) [Member]
Common stock reserved for issuance (in shares)	808,310	0
Future Grants of Equity Awards [Member]
Common stock reserved for issuance (in shares)	12,074,692	5,582,742
ESPP [Member]
Common stock reserved for issuance (in shares)	1,800,000	0

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
Consolidated Statements of Cash Flows - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net loss	$ (107,758,000)	$ (70,470,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	5,805,000	4,208,000
Accretion of (discount) premium on investments	(163,000)	85,000
Impairment of intangible assets	4,254,000	3,005,000
Stock-based compensation	13,587,000	8,867,000
Gain on remeasurement of future royalty liability	(6,960,000)	(3,789,000)
Non-cash interest expense related to sale of future royalties	1,305,000	1,480,000
Non-cash revenue related to sale of future royalties	(151,000)	(1,098,000)
Change in operating assets and liabilities:
Accounts receivable	51,000	263,000
Prepaid expenses and other assets	(3,783,000)	(1,800,000)
Accounts payable	357,000	1,626,000
Deferred grant revenue	2,000,000	0
Accrued liabilities	(3,323,000)	(2,209,000)
Net cash used in operating activities	(94,779,000)	(59,832,000)
Cash flows from investing activities:
Purchase of property and equipment	(9,601,000)	(5,157,000)
Acquisition of business, net of cash acquired	0	(4,829,000)
Purchases of investments	(55,014,000)	(44,811,000)
Proceeds from maturities of investments	44,200,000	5,700,000
Net cash used in investing activities	(20,415,000)	(49,097,000)
Cash flows from financing activities:
Net proceeds from issuance of common stock through at-the-market facilities	17,237,000	122,210,000
Proceeds from issuance of common stock upon exercise of common stock warrants	2,000	1,849,000
Proceeds from issuance of common stock upon exercise of stock options	223,000	1,745,000
Net cash provided by financing activities	17,462,000	125,804,000
Net (decrease) increase in cash, cash equivalents and restricted cash	(97,732,000)	16,875,000
Cash, cash equivalents and restricted cash at beginning of the period	143,745,000	126,870,000
Cash, cash equivalents and restricted cash at end of the period	46,013,000	143,745,000
Supplemental disclosure of non-cash investing and financing activity:
Operating lease liabilities arising from obtaining right-of-use assets	9,997,000	8,395,000
Lease-related assets and liabilities derecognized on early termination and modification of leases	0	321,000
Acquisition of property and equipment included in accounts payable and accrued expenses	1,803,000	453,000
Cash and cash equivalents	44,013,000	143,745,000
Restricted cash	2,000,000	0
Cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows	$ 46,013,000	$ 143,745,000

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Revenue from Contract with Customer, Including Assessed Tax	$ 107	$ 892
Operating expenses:
Research and development	81,054	48,749
General and administrative	29,386	21,890
Impairment of intangible assets	4,254	3,005
Total operating expenses	114,694	73,644
Operating loss	(114,587)	(72,752)
Other income (expense):
Interest income	1,247	81
Non-cash interest expense related to sale of future royalties	(1,305)	(1,480)
Gain on remeasurement of future royalty liability	6,960	3,789
Foreign exchange loss, net	(6)	(1)
Loss before income taxes	(107,691)	(70,363)
Provision for income taxes	67	107
Net loss	$ (107,758)	$ (70,470)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.84)	$ (0.58)
Shares used to compute net loss per share, basic and diluted (in shares)	127,683,813	121,453,723
Comprehensive loss:
Net loss	$ (107,758)	$ (70,470)
Unrealized loss on available-for-sale investments, net of tax	(225)	(74)
Comprehensive loss	(107,983)	(70,544)
Customer Service Contracts [Member]
Revenue from Contract with Customer, Including Assessed Tax	0	13
Non Cash Royalty Revenue [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 107	$ 879

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash, cash equivalents and restricted cash	$ 46,013	$ 143,745
Short-term investments	49,704	22,742
Accounts receivable	20	71
Prepaid expenses and other current assets	3,714	2,609
Total current assets	99,451	169,167
Long-term investments	0	16,210
Property and equipment, net	15,585	6,601
Right-of-use assets, net	25,715	13,168
Intangible assets, net	5,020	10,624
Goodwill	4,508	4,508
Other long-term assets	3,568	890
Total assets	153,847	221,168
Current liabilities:
Accounts payable	5,514	3,872
Deferred grant revenue	2,000	0
Other accrued current liabilities	8,084	5,064
Current portion of operating lease liability	2,228	1,011
Current portion of liability related to sale of future royalties	95	836
Total current liabilities	17,921	10,783
Operating lease liability, net of current portion	19,477	11,997
Liability related to sale of future royalties, net of current portion	5,621	10,686
Other long-term liabilities	231	171
Total liabilities	43,250	33,637
Commitments and contingencies (Note 9)
Stockholders’ equity:
Preferred Stock: $0.0001 par value; 5,000,000 shares authorized; none issued and outstanding as of December 31, 2022 or 2021	0	0
Common Stock: $0.0001 par value; 250,000,000 and 150,000,000 shares authorized as of December 31, 2022 and 2021, respectively; 134,199,429 and 125,594,393 shares issued and outstanding as of December 31, 2022 and 2021, respectively	13	13
Additional paid-in capital	437,992	406,943
Accumulated deficit	(327,109)	(219,351)
Accumulated other comprehensive loss	(299)	(74)
Total stockholders’ equity	110,597	187,531
Total liabilities and stockholders’ equity	$ 153,847	$ 221,168

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2022

Accounting Policies [Abstract]

Basis of Presentation, Liquidity and Going Concern – The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and pursuant to the accounting and disclosure rules and regulations of the Securities and Exchange Commission (the “SEC”), assuming the Company will continue as a going concern.

The Company is a clinical-stage biotechnology company with no product sales. Its primary source of capital is from the sale and issuance of common stock and common stock warrants. At December 31, 2022, the Company had cash, cash equivalents, restricted cash, and investments of $95.7 million. A substantial doubt has been raised with regard to the ability of the Company to continue as a going concern as the Company experienced negative cash flow from operating activities of $94.8 million in 2022 and had no committed source of debt or equity financing.

Subsequent to December 31, 2022, the Company decided to prioritize development of its norovirus oral vaccine candidate (see Note 15). As a result of the prioritization, the Company projects it has enough cash runway into the second quarter of 2024.

The Company will be dependent upon raising additional capital through placement of its common stock, notes or other securities, borrowings, or entering into a partnership with a strategic party in order to implement its business plan. There can be no assurance that the Company will be successful raising additional capital in order to continue as a going concern.

The financial statements do not include any adjustments that might be necessary if the Company is unable to continue as a going concern.

Consolidation, Policy [Policy Text Block]

Basis of Consolidation – The consolidated financial statements include the financial statements of Vaxart, Inc. and its subsidiaries. All significant transactions and balances between Vaxart, Inc. and its subsidiaries have been eliminated in consolidation.

Use of Estimates, Policy [Policy Text Block]

Use of Estimates – The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities (including accrued clinical and manufacturing accruals described within this Note 2), revenues and expenses and disclosure of contingent assets and liabilities in the financial statements and accompanying notes. Actual results and outcomes could differ from these estimates and assumptions.

Foreign Currency Transactions and Translations Policy [Policy Text Block]

Foreign Currencies – Foreign exchange gains and losses for assets and liabilities of the Company’s non-U.S. subsidiaries for which the functional currency is the U.S. dollar are recorded in foreign exchange gain or loss, net within other income and (expenses) in the Company’s consolidated statements of operations and comprehensive loss. The Company has no subsidiaries for which the local currency is the functional currency.

Cash and Cash Equivalents, Policy [Policy Text Block]

Cash, Cash Equivalents and Restricted Cash – The Company considers all highly liquid debt investments with an original maturity of three months or less when purchased to be cash equivalents. Cash equivalents, which may consist of amounts invested in money market funds, corporate bonds and commercial paper, are stated at fair value. The Company’s restricted cash includes refundable advance payments received as of December 31, 2022 and 2021 of $2.0 million and zero, respectively.

Investment, Policy [Policy Text Block]

Investments – Excess cash balances may be invested in marketable debt securities. All investments that are readily convertible to known amounts of cash with stated maturities greater than three months when purchased are classified as investments.

The Company determines the appropriate classification of its investments in marketable securities at the time of purchase and reevaluates such designation at each balance sheet date. Marketable debt securities are classified and accounted for as available-for-sale. After consideration of the Company’s objectives to preserve capital, as well as its liquidity requirements, it may sell these debt securities prior to their stated maturities. These securities are carried at fair value and unrealized gains and losses, net of taxes, are reported as a component of stockholders’ equity, except for unrealized losses determined to be other-than-temporary, which are recorded within other income (expense). Any realized gains or losses on the sale of marketable debt securities are determined on a specific identification method, and such gains and losses are recorded as a component of other income (expense). Available-for-sale investments are classified as either current or non-current assets based on each instrument’s underlying effective maturity date and whether the Company has the intent and ability to hold the investment for a period of greater than 12 months. Marketable securities with remaining maturities of 12 months or less are classified as current and are reported as short-term investments in the consolidated balance sheets. Marketable securities with remaining maturities of more than 12 months for which the Company has the intent and ability to hold the investment for more than 12 months are classified as non-current and are included in long-term investments in the consolidated balance sheets.

Securities are evaluated for impairment at the end of each reporting period. Impairment is evaluated considering numerous factors, including whether a decline in fair value below the amortized cost basis is due to credit-related factors or non-credit-related factors, the financial condition and near-term prospects of the issuer, and intent and ability to hold the investment to allow for an anticipated recovery in fair value. A credit-related impairment is recognized as an allowance on the balance sheet with a corresponding adjustment to earnings. Any impairment that is not credit-related is recognized in other comprehensive loss, net of applicable taxes.

Concentration Risk, Credit Risk, Policy [Policy Text Block]

Concentration of Credit Risk – Financial instruments that potentially subject the Company to significant concentrations of credit risk consist principally of cash, cash equivalents, restricted cash and available-for-sale investments. The Company places its cash, cash equivalents, restricted cash and available-for-sale investments at financial institutions that management believes are of high credit quality. The Company is exposed to credit risk in the event of default by the financial institutions holding the cash, cash equivalents and restricted cash to the extent such amounts are in excess of the federally insured limits. Losses incurred or a lack of access to such funds could have a significant adverse impact on the Company’s financial condition, results of operations, and cash flows.

The primary focus of the Company’s investment strategy is to preserve capital and meet liquidity requirements. The Company’s investment policy addresses the level of credit exposure by limiting the concentration in any one corporate issuer or sector and establishing a minimum allowable credit rating.

Receivable [Policy Text Block]

Accounts Receivable – Accounts receivable arise from the Company’s royalty revenue receivable for sales, net of estimated returns, of Inavir and are reported at amounts expected to be collected in future periods. An allowance for uncollectible accounts will be recorded based on a combination of historical experience, aging analysis and information on specific accounts, with related amounts recorded as a reserve against revenue recognized. Account balances will be written off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. The Company has provided no allowance for uncollectible accounts as of December 31, 2022 and 2021.

Property, Plant and Equipment, Policy [Policy Text Block]

Property and Equipment – Property and equipment is carried at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the respective assets. Depreciation begins at the time the asset is placed in service. Maintenance and repairs are charged to operations as incurred. Upon sale or retirement of assets, the cost and related accumulated depreciation are removed from the balance sheet and the resulting gain or loss is reflected in other income and (expenses) in the period realized.

The useful lives of the property and equipment are as follows:

Laboratory equipment (in years)			5
Office and computer equipment (in years)			3
Leasehold improvements			Shorter of remaining lease term or estimated useful life

Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block]

Goodwill and Other Intangible Assets – Goodwill, which represents the excess of the purchase price over the fair value of assets acquired, is not amortized. Intangible assets comprise developed technology and intellectual property. Intangible assets are carried at cost less accumulated amortization. Amortization is computed using the straight-line method over useful life of 11.75 years for developed technology and 20 years for intellectual property.

Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]

Impairment of Long-Lived Assets – The Company reviews its long-lived assets, including property and equipment, goodwill and intangible assets with finite lives, for impairment in the fourth quarter of each year, and more frequently whenever events or changes in circumstances indicate the carrying amount of these assets may not be recoverable. Recoverability of these assets is measured by comparison of the carrying amount of each asset to the future undiscounted cash flows the asset is expected to generate over its remaining life. When indications of impairment are present and the estimated undiscounted future cash flows from the use of these assets is less than the assets’ carrying value, the related assets will be written down to fair value. The Company assessed its developed technology as impaired in the years ended December 31, 2022 and 2021 (see Note 7).

Accrued Clinical And Manufacturing Expenses Policy [Policy Text Block]

Accrued Clinical and Manufacturing Expenses – The Company accrues for estimated costs of research and development activities conducted by third-party service providers, which include the conduct of preclinical studies and clinical trials, and contract manufacturing activities. The Company records the estimated costs of research and development activities based upon the estimated amount of services provided and includes the costs incurred but not yet invoiced within other accrued liabilities in the balance sheets and within research and development expense in the consolidated statements of operations and comprehensive loss. These costs can be a significant component of the Company’s research and development expenses.

The Company estimates the amount of services provided through discussions with internal personnel and external service providers as to the progress or stage of completion of the services and the agreed-upon fee to be paid for such services. The Company makes significant judgments and estimates in determining the accrued balance in each reporting period. As actual costs become known, it adjusts its accrued estimates. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of the status and timing of services performed, the number of subjects enrolled, and the rate of enrollment may vary from its estimates and could result in the Company reporting amounts that are too high or too low in any particular period. The Company’s accrued expenses are dependent, in part, upon the receipt of timely and accurate reporting from contract research organizations and other third-party service providers. To date, the Company has not experienced any material differences between accrued costs and actual costs incurred.

Lessee, Leases [Policy Text Block]

Leases – The Company records operating leases as right-of-use assets and operating lease liabilities in its consolidated balance sheets for all operating leases with terms exceeding one year. Right-of-use assets represent the right to use an underlying asset for the lease term, including extension options considered reasonably certain to be exercised, and operating lease liabilities to make lease payments. Right-of-use assets and operating lease liabilities are recognized based on the present value of lease payments over the lease term. To the extent that lease agreements do not provide an implicit rate, the Company uses its incremental borrowing rate based on information available at the lease commencement date to determine the present value of lease payments. The expense for operating lease payments is recognized on a straight-line basis over the lease term and is included in operating expenses in the Company’s consolidated statement of operations and comprehensive loss. The Company has elected to not separate lease and non-lease components of facilities leases, whereas non-lease components of equipment leases are accounted for separately from lease components.

Revenue [Policy Text Block]

Revenue Recognition – The Company recognizes revenue when it transfers control of promised goods or services to its customers, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods or services. To determine revenue recognition, the Company performs the following five steps:

(i)

identification of the promised goods or services in the contract;

(ii)

determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract;

(iii)

measurement of the transaction price, including the constraint on variable consideration;

(iv)

allocation of the transaction price to the performance obligations based on estimated selling prices; and

(v)

recognition of revenue when (or as) the Company satisfies each performance obligation. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account.

Revenue from royalties earned as a percentage of sales, including milestone payments based on achieving a specified level of sales, where a license is deemed to be the predominant item to which the royalties relate, is recognized as revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied), as required under the sales- and usage-based royalty exception.

Revenue from contracts with customers is recognized ratably, based on costs incurred, as the Company provides promised services to its customers in amounts that reflect the consideration that the Company expects to receive for those services.

In 2022, the Company accepted a grant to perform research and development work for the Bill & Melinda Gates Foundation (BMGF). The Company recognizes revenue under research contracts only when a contract has been executed and the contract price is fixed or determinable. Revenue from the BMGF grant is recognized in the period during which the related costs are incurred and the related services are rendered, provided that the applicable conditions under the contract have been met. Costs of contract revenue are recorded as a component of operating expenses in the consolidated statements of operations and comprehensive loss. The Company recognized no revenue from the BMGF Grant in the year ended December 31, 2022. The $2.0 million received from the BMGF is recorded as deferred grant revenue.

Under cost reimbursable contracts, the Company recognizes revenue as allowable costs are incurred and the fixed fee is earned. Reimbursable costs under the contract primarily include direct labor, subcontract costs, materials, equipment, travel, and approved overhead and indirect costs. Fixed fees under cost reimbursable contracts are earned in proportion to the allowable costs incurred in performance of the work relative to total estimated contract costs, with such costs incurred representing a reasonable measurement of the proportional performance of the work completed.

Payments to the Company under cost reimbursable contracts, such as this contract, are provisional payments subject to adjustment upon annual audit by the government. Management believes that revenue for periods not yet audited has been recorded in amounts that are expected to be realized upon final audit and settlement. When the final determination of the allowable costs for any year has been made, revenue and billings may be adjusted accordingly in the period that the adjustment is known.

Research and Development Expense, Policy [Policy Text Block]

Research and Development Costs – Research and development costs are expensed as incurred. Research and development costs consist primarily of salaries and benefits, stock-based compensation, consultant fees, third-party costs for conducting clinical trials and the manufacture of clinical trial materials, certain facility costs and other costs associated with clinical trials. Payments made to other entities are under agreements that are generally cancelable by the Company. Advance payments for research and development activities are recorded as prepaid expenses. The prepaid amounts are expensed as the related services are performed.

Share-Based Payment Arrangement [Policy Text Block]

Stock-Based Compensation – Stock-based compensation arrangements include stock option grants and restricted stock units (“RSU”s) awards under our equity incentive plans, as well as shares issued under our Employee Stock Purchase Plan (“ESPP”), through which employees may purchase our common stock at a discount to the market price. Stock-based compensation is measured at the grant date for all stock-based awards made to employees and non-employees based on the fair value of the awards, net of estimated forfeitures. Compensation expense for purchases under the ESPP is recognized based on the fair value of the award on the date of offering. The fair value of these awards is estimated using the Black-Scholes valuation model. The expected term of each option is estimated by taking the arithmetic average of its original contractual term and its average vesting term.

Earnings Per Share, Policy [Policy Text Block]

Net Income (Loss) Per Share – Basic net income (loss) per share is computed by dividing net income (loss) by the weighted average number of common shares outstanding during the period, without consideration of potential common shares.

Diluted net income (loss) per common share is computed giving effect to all potential dilutive common shares, comprising common stock issuable upon exercise of stock options, warrants, RSUs and ESPP. The Company uses the treasury-stock method to compute diluted income (loss) per share with respect to its stock options, warrants, RSUs and ESPP. For purposes of this calculation, options, warrants, RSUs and ESPP plan grants to purchase common stock are considered to be potential common shares and are only included in the calculation of diluted net income per share when their effect is dilutive. In the event of a net loss, the effects of all potentially dilutive shares are excluded from the diluted net loss per share calculation as their inclusion would be antidilutive.

New Accounting Pronouncements, Policy [Policy Text Block]

Recent Accounting Pronouncements

The Company has reviewed all significant newly-issued accounting pronouncements that are not yet effective and concluded that they are either not applicable to its operations or their adoption will not have a material impact on its financial position or results of operations.

Note 13 - Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Beginning Balance	$ 2,422	$ 1,281
Additions based on tax positions related to the current year	2,589	1,132
Decrease related to prior years’ tax positions	(66)
Increase related to prior years’ tax positions		9
Ending Balance	$ 4,945	$ 2,422

Note 2 - Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2022

Schedule of Property, Plant, and Equipment, Useful Life [Table Text Block]

Laboratory equipment (in years)			5
Office and computer equipment (in years)			3
Leasehold improvements			Shorter of remaining lease term or estimated useful life

Note 13 - Income Taxes - Reconciliation of Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2019
U.S. federal taxes at statutory rate	21.00%	21.00%	21.00%
State taxes (net of federal benefit)	0.10%	4.00%
Foreign rate differential	(0.30%)	0.30%
Permanently non-deductible items	(1.50%)	0.20%
Tax credits	3.00%	3.40%
Change in valuation allowance	(22.00%)	(29.30%)
Tax attributes write-off due to change in control	0.00%	0.00%
Prior year true-up	(0.20%)	0.60%
Other	(0.20%)	(0.30%)
Provision for income taxes	(0.10%)	(0.10%)

Note 10 - Stockholders' Equity

12 Months Ended

Dec. 31, 2022

Stockholders' Equity Note Disclosure [Text Block]

NOTE 10. Stockholders’ Equity

(a) Preferred Stock

The Company is authorized to issue 5,000,000 shares of preferred stock, $0.0001 par value per share. The Company’s board of directors may, without further action by the stockholders, fix the rights, preferences, privileges and restrictions of up to an aggregate of 5,000,000 shares of preferred stock in one or more series and authorize their issuance. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of such series, any or all of which may be greater than the rights of our common stock. The issuance of preferred stock could adversely affect the voting power of holders of common stock and the likelihood that such holders will receive dividend payments and payments upon liquidation. In addition, the issuance of preferred stock could have the effect of delaying, deterring or preventing a change of control or other corporate action. No shares of preferred stock are currently outstanding, and the Company has no present plan to issue any shares of preferred stock.

(b) Common Stock

As of December 31, 2022, the Company was authorized to issue 250,000,000 shares of common stock, $0.0001 par value per share, which includes an increase of 100,000,000 on August 4, 2022, when the Company’s stockholders approved an amendment to the Company’s certificate of incorporation to increase the number of authorized shares of common stock from 150,000,000. Except as otherwise required by law or as otherwise provided in any certificate of designation for any series of preferred stock, the holders of common stock possess all voting power for the election of the Company’s directors and all other matters requiring stockholder action. Holders of common stock are entitled to one vote per share on matters to be voted on by stockholders. Holders of common stock are entitled to receive such dividends, if any, as may be declared from time to time by the Company’s board of directors in its discretion out of funds legally available therefor. In no event will any stock dividends or stock splits or combinations of stock be declared or made on common stock unless the shares of common stock at the time outstanding are treated equally and identically. As of December 31, 2022, no dividends had been declared by the board of directors.

In the event of the Company’s voluntary or involuntary liquidation, dissolution, distribution of assets or winding-up, the holders of the common stock will be entitled to receive an equal amount per share of all the Company’s assets of whatever kind available for distribution to stockholders, after the rights of the holders of the preferred stock have been satisfied. There are no sinking fund provisions applicable to the common stock.

The Company had shares of common stock reserved for issuance as follows:

	*December 31, 2022*		*December 31, 2021*

Options issued and outstanding		14,725,261		10,216,106
RSUs issued and outstanding		808,310		—
Available for future grants of equity awards		12,074,692		5,582,742
Common stock warrants		227,434		232,434
2022 Employee Stock Purchase Plan		1,800,000		—
Total		29,635,697		16,031,282

(c) Warrants

The Company has the following warrants outstanding as of December 31, 2022, all of which contain standard anti-dilution protections in the event of subsequent rights offerings, stock splits, stock dividends or other extraordinary dividends, or other similar changes in the Company’s common stock or capital structure, and none of which have any participating rights for any losses:

Securities into which warrants are convertible	Warrants outstanding		Exercise Price		Expiration Date

Common Stock		44,148	$	1.10	April 2024
Common Stock		26,515	$	1.375	April 2024
Common Stock		29,150	$	2.50	March 2025
Common Stock		100,532	$	3.125	February 2025
Common Stock		16,175	$	3.125	March 2024
Common Stock		10,914	$	22.99	December 2026
Total		227,434

In the event of a Fundamental Transaction (a transfer of ownership of the Company as defined in the warrant) within the Company’s control, the holders of the unexercised common stock warrants exercisable for $1.10 and $2.50 and those exercisable for $3.125 expiring in February 2025 shall be entitled to receive cash consideration equal to a Black-Scholes valuation, as defined in the warrant. If such Fundamental Transaction is not within the Company’s control, the warrant holders would only be entitled to receive the same form of consideration (and in the same proportion) as the holders of the Company’s common stock, hence these warrants are classified as a component of permanent equity.

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

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Note 5 - Balance Sheet Components - Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Intangible assets, gross	$ 5,080	$ 10,680
Less: accumulated amortization	(60)	(56)
Intangible assets, net	5,020	10,624
Developed Technology Rights [Member]
Intangible assets, gross	5,000	10,600
Intellectual Property [Member]
Intangible assets, gross	$ 80	$ 80

Note 8 - Leases - Operating Lease Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Operating lease cost	$ 4,159	$ 2,513
Short-term lease cost	436	340
Variable lease cost	1,312	1,233
Sublease income	0	(36)
Total lease cost	$ 5,907	$ 4,050

Note 10 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Aug. 04, 2022	Dec. 31, 2022	Aug. 03, 2022	Dec. 31, 2021
Preferred Stock, Shares Authorized (in shares)		5,000,000		5,000,000
Preferred Stock, Par or Stated Value Per Share (in dollars per share)		$ 0.0001		$ 0.0001
Preferred Stock, Shares Outstanding, Ending Balance (in shares)		0		0
Common Stock, Shares Authorized (in shares)		250,000,000	150,000,000	150,000,000
Common Stock, Par or Stated Value Per Share (in dollars per share)		$ 0.0001		$ 0.0001
Common Stock, Increase in Shares Authorized (in shares)	100,000,000
Dividends, Total		$ 0
First Set of Warrants Expiring April 2024 [Member]
Warrant Exercise Price to be Entitled to Receive Cash Consideration, Fundamental Transaction (in dollars per share)		$ 1.10
Warrants Expiring March 2025 [Member]
Warrant Exercise Price to be Entitled to Receive Cash Consideration, Fundamental Transaction (in dollars per share)		2.50
Warrants Expiring February 2025 [Member]
Warrant Exercise Price to be Entitled to Receive Cash Consideration, Fundamental Transaction (in dollars per share)		$ 3.125

Note 14 - Net Loss Per Share Attributable to Common Stockholders

12 Months Ended

Dec. 31, 2022

Earnings Per Share [Text Block]

NOTE 14. Net Loss Per Share Attributable to Common Stockholders

The following table presents the calculation of basic and diluted net loss per share (in thousands, except share and per share amounts):

	*Year Ended December 31,*
	*2022*			*2021*

Net loss	$	(107,758	)	$	(70,470	)

Shares used to compute net loss per share, basic and diluted		127,683,813			121,453,723

Net loss per share attributable to common stockholders, basic and diluted	$	(0.84	)	$	(0.58	)

No adjustment has been made to the net loss attributable to common stockholders as the effect would be anti-dilutive due to the net loss.

The following potentially dilutive weighted average securities were excluded from the computation of weighted average shares outstanding because they would have been antidilutive:

	*Year Ended December 31,*
	*2022*		*2021*

Options to purchase common stock	13,567,390			8,206,137
Restricted stock unit to purchase common stock		460,975		—
Warrants to purchase common stock	228,725			369,043
Employee Stock Purchase Plan		392,095		—

Total potentially dilutive securities excluded from denominator of the diluted earnings per share computation		14,649,185		8,575,180

Note 14 - Net Loss Per Share Attributable to Common Stockholders - Calculation of Basic and Diluted Net (Loss) Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Net loss	$ (107,758)	$ (70,470)
Shares used to compute net loss per share, basic and diluted (in shares)	127,683,813	121,453,723
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.84)	$ (0.58)

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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Note 3 - Business Combination - Allocation of the Purchase Price to the Fair Value of the Respective Assets and Liabilities Acquired (Details) - USD ($) $ in Thousands	Nov. 30, 2021	Dec. 31, 2022	Dec. 31, 2021
Goodwill, Ending Balance		$ 4,508	$ 4,508
Acquisition of Kindred BioSciences [Member]
Business combination, property and equipment acquired	$ 321
Goodwill, Ending Balance	4,508
Business Combination, Consideration Transferred, Total	$ 4,829

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References + Details

Note 8 - Leases - Lease Liabilities Payment Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
2023	$ 4,072
2024	4,213
2025	4,356
2026	4,964
2027	5,138
Thereafter	6,649
Undiscounted total	29,392
Less: imputed interest	(7,687)
Present value of future minimum payments	21,705
Current portion of operating lease liability	(2,228)	$ (1,011)
Operating lease liability, net of current portion	$ 19,477	$ 11,997

Note 4 - Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2022

Fair Value, Assets Measured on Recurring Basis [Table Text Block]

	*Level 1*		*Level 2*		*Level 3*		*Total*
December 31, 2022
Financial assets:
Money market funds	$	30,834	$	—	$	—	$	30,834
U.S. Treasury securities		—		41,542		—		41,542
Commercial paper		—		5,674		—		5,674
Corporate debt securities		—		2,488		—		2,488

Total assets	$	30,834	$	49,704	$	—	$	80,538

	*Level 1*		*Level 2*		*Level 3*		*Total*
December 31, 2021
Financial assets:
Money market funds	$	70,978	$	—	$	—	$	70,978
U.S. Treasury securities		—		24,997		—		24,997
Commercial paper		—		7,491		—		7,491
Corporate debt securities		—		6,464		—		6,464

Total assets	$	70,978	$	38,952	$	—	$	109,930

Note 11 - Equity Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement, Option, Activity [Table Text Block]

							*Weighted*					*Weighted*
	*Shares*			*Number of*			*Option Average*		*Number of*			*RSU Average*
	*Available*			*Options*			*Exercise*		*RSUs*			*Grant Date*
	*For Grant*			*Outstanding*			*Price*		*Outstanding*			*Fair Value*

Balance at January 1, 2021		1,230,863			6,813,033		$	2.70		—		$	—

Authorized under 2019 Plan Amendment		8,900,000			—		$	—		—		$	—
Granted		(5,178,438	)		5,178,438		$	7.09		—		$	—
Exercised		—			(1,070,921	)	$	1.63		—		$	—
Forfeited		630,317			(650,054	)	$	3.16		—		$	—
Canceled		—			(54,390	)	$	11.98		—		$	—

Balance at December 31, 2021		5,582,742			10,216,106		$	4.96		—		$	—

Authorized under 2019 Plan Amendment		12,000,000			—		$	—		—		$	—
Granted		(7,291,935	)		6,376,657		$	4.10		915,278		$	3.58
Exercised		—			(180,336	)	$	1.24		—		$	—
Forfeited		1,625,133			(1,518,230	)	$	6.19		(106,968	)	$	3.62
Canceled		158,752			(168,936	)	$	7.17		—		$	—

Balance at December 31, 2022		12,074,692			14,725,261		$	4.48		808,310		$	3.57

Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Year Ended December 31,
	2022			2021

Risk-free interest rate		1.62% - 4.02	%		0.91% - 1.35	%
Expected term (in years)		5.42 - 6.08			5.44 - 6.08
Expected volatility		125% - 131	%		122% - 131	%
Dividend yield		—	%		—	%

Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]

	*Year Ended December 31,*
	*2022*		*2021*

Research and development	$	9,183	$	4,304
General and administrative		4,404		4,563
Total stock-based compensation	$	13,587	$	8,867

Note 1 - Organization and Nature of Business (Details Textual) - USD ($) $ in Thousands			9 Months Ended	11 Months Ended	12 Months Ended
	Sep. 15, 2021	Oct. 13, 2020	Sep. 30, 2021	Sep. 13, 2021	Dec. 31, 2022	Dec. 31, 2021
Proceeds from Issuance of Common Stock					$ 17,237	$ 122,210
The October 2020 Offering [Member]
Open Market Sale Agreement, Maximum Aggregate Offering Price		$ 250,000
Payments of Stock Issuance Costs		$ 300
Open Market Sale Agreement, Sales Commission, Percentage		4.50%
Stock Issued During Period, Shares, New Issues (in shares)			13,239,839	13,932,490
Proceeds from Issuance of Common Stock			$ 127,900	$ 133,400
Proceeds from Issuance of Common Stock, Net			$ 122,200	$ 127,100
The September 2021 ATM [Member]
Open Market Sale Agreement, Maximum Aggregate Offering Price	$ 100,000
Open Market Sale Agreement, Sales Commission, Percentage	3.00%
Stock Issued During Period, Shares, New Issues (in shares)					8,419,700
Proceeds from Issuance of Common Stock					$ 18,000
Proceeds from Issuance of Common Stock, Net					$ 17,200

Note 5 - Balance Sheet Components

12 Months Ended

Dec. 31, 2022

Supplemental Balance Sheet Disclosures [Text Block]

NOTE 5. Balance Sheet Components

(a)     Cash, Cash Equivalents, Restricted Cash and Investments

Cash, cash equivalents, restricted cash and investments consisted of the following (in thousands):

Amortized

Gross Unrealized

Estimated

Cash, Cash Equivalents

Short-Term

Long-Term

Cost

Gains

Losses

Fair Value

and Restricted Cash

Investments

Investments

December 31, 2022

Cash at banks
$ 15,179 $ — $ — $ 15,179 $ 15,179 $ — $ —

Money market funds
30,834 — — 30,834 30,834 — —

U.S. Treasury securities
41,812 — (270 ) 41,542 — 41,542 —

Commercial paper
2,488 — — 2,488 — 2,488 —

Corporate debt securities
5,703 — (29 ) 5,674 — 5,674 —

Total
$ 96,016 $ — $ (299 ) $ 95,717 $ 46,013 $ 49,704 $ —

Amortized

Gross Unrealized

Estimated

Cash and Cash

Short-Term

Long-Term

Cost

Gains

Losses

Fair Value

Equivalents

Investments

Investments

December 31, 2021

Cash at banks
$ 72,767 $ — $ — $ 72,767 $ 72,767 $ — $ —

Money market funds
70,978 — — 70,978 70,978 — —

U.S. Treasury securities
25,055 — (58 ) 24,997 — 12,022 12,975

Commercial paper
7,491 — — 7,491 — 7,491 —

Corporate debt securities
6,480 — (16 ) 6,464 — 3,229 3,235

Total
$ 182,771 $ — $ (74 ) $ 182,697 $ 143,745 $ 22,742 $ 16,210

(b)     Accounts Receivable

Accounts receivable comprises royalties receivable of $20,000 and $71,000 as of December 31, 2022 and 2021, respectively. The Company has provided no allowance for uncollectible accounts as of December 31, 2022 and 2021.

(c)     Property and Equipment, Net

Property and equipment, net consists of the following (in thousands):

December 31, 2022 December 31, 2021

Laboratory equipment
$ 12,035 $ 5,057

Office and computer equipment
1,078 481

Leasehold improvements
1,760 1,063

Construction in progress
3,984 1,305

Total property and equipment
18,857 7,906

Less: accumulated depreciation
(3,272 ) (1,305 )

Property and equipment, net
$ 15,585 $ 6,601

Depreciation expense was $1,967,000, and $732,000 the years ended December 31, 2022 and 2021, respectively. There were no impairments of the Company’s property and equipment recorded in the years ended December 31, 2022 or 2021.

(d) Right-of-Use Assets, Net

Right-of-use assets, net comprises facilities of $25.7 million and $13.2 million as of December 31, 2022 and 2021, respectively. The right of use of one of the Company’s leased premises in California commenced in 2022, resulting in an additional $15.0 million right of use asset recorded (see Note 8).

(e)     Intangible Assets, Net

Intangible assets comprise developed technology, intellectual property and, until it was considered fully impaired, in-process research and development. Intangible assets are carried at cost less accumulated amortization. Amortization is computed using the straight-line method over useful life of 11.75 years for developed technology and 20 years for intellectual property. As of December 31, 2022, developed technology and intellectual property had remaining lives of 6.9 and 5.0 years, respectively. Intangible assets consist of the following (in thousands):

December 31, 2022

December 31, 2021

Developed technology
$ 5,000 $ 10,600

Intellectual property
80 80

Total cost
5,080 10,680

Less: accumulated amortization
(60 ) (56 )

Intangible assets, net
$ 5,020 $ 10,624

Intangible asset amortization expense was $1.3 million and $1.7 million for the years ended December 31, 2022 and 2021, respectively. Due to a decline in royalties earned since the outbreak of COVID-19 (see Note 7), developed technology was assessed as partially impaired as of December 31, 2022 and 2021, and accordingly impairment charges of $4.3 million and $3.0 million, respectively, were recorded within operating expenses.

As of December 31, 2022, the estimated future amortization expense by year is as follows (in thousands):

Year Ending December 31,

Amount

2023
$ 731

2024
731

2025
731

2026
731

2027
731

Thereafter
1,365

Total
$ 5,020

(f) Goodwill

Goodwill, which represents the excess of the purchase price over the fair value of assets acquired, comprises $4.5 million for both years ended December 31, 2022 and 2021. For the year ended December 31, 2022 there was no change in Goodwill and for the year ended December 31, 2021, the only activity was the 2021 acquisition as further described in Note 4. As of December 31, 2022 and 2021, there have been no indicators of impairment.

(g) Other Accrued Liabilities

Other accrued liabilities consist of the following (in thousands):

December 31, 2022

December 31, 2021

Accrued compensation
$ 3,112 $ 2,786

Accrued clinical and manufacturing expenses
2,413 986

Accrued professional and consulting services
691 556

Accrued other expenses
1,868 736

Total
$ 8,084 $ 5,064

Note 4 - Fair Value of Financial Instruments (Details Textual) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Recurring [Member]
Financial Liabilities Fair Value Disclosure, Total	$ 0	$ 0

Note 11 - Equity Incentive Plans - Summary of Stock Option Transactions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Shares available for grant, balance (in shares)	5,582,742	1,230,863
Number of options outstanding, beginning balance (in shares)	10,216,106	6,813,033
Weighted average exercise price, balance (in dollars per share)	$ 4.96	$ 2.70
Shares availabe for grant, 2019 Plan Amendment (in shares)	12,000,000	8,900,000
Shares available for grant, granted (in shares)	(7,291,935)	(5,178,438)
Number of options outstanding, granted (in shares)	6,376,657	5,178,438
Weighted average exercise price, granted (in dollars per share)	$ 4.10	$ 7.09
Number of options outstanding, exercised (in shares)	(180,336)	(1,070,921)
Weighted average exercise price, exercised (in dollars per share)	$ 1.24	$ 1.63
Shares available for grant, forfeited (in shares)	1,625,133	630,317
Number of options outstanding, forfeited (in shares)	(1,518,230)	(650,054)
Weighted average exercise price, forfeited (in dollars per share)	$ 6.19	$ 3.16
Shares available for grant, canceled (in shares)	158,752	0
Number of options outstanding, canceled (in shares)	(168,936)	(54,390)
Weighted average exercise price, canceled (in dollars per share)	$ 7.17	$ 11.98
Shares available for grant, balance (in shares)	12,074,692	5,582,742
Number of options outstanding, balance (in shares)	14,725,261	10,216,106
Weighted average exercise price, balance (in dollars per share)	$ 4.48	$ 4.96
Restricted Stock Units (RSUs) [Member]
Weighted average exercise price, balance (in dollars per share)	0	0
Weighted average exercise price, granted (in dollars per share)	3.58	0
Weighted average exercise price, exercised (in dollars per share)	0	0
Weighted average exercise price, forfeited (in dollars per share)	3.62	0
Weighted average exercise price, canceled (in dollars per share)	$ 0	0
Granted (in shares)	915,278
Exercised (in shares)	0
Forfeited (in shares)	(106,968)
Weighted average exercise price, balance (in dollars per share)	$ 3.57	$ 0
Balance at December 31, 2022 (in shares)	808,310

Note 15 - Subsequent Events

12 Months Ended

Dec. 31, 2022

Subsequent Events [Text Block]

NOTE 15. Subsequent Events

Since December 31, 2022, the Company has issued 1,362,220 shares of common stock under the September 2021 ATM (see Note 1) for net proceeds totaling $1.5 million through March 14, 2023.

Changes in the status of litigation since December 31, 2022, are included in “Note 9. Commitments and Contingencies—(c) Litigation”.

In the first quarter of 2023, the Company decided to primarily focus on advancing its norovirus oral vaccine candidate and postponed initiating a SARS-CoV-2 human challenge study. The Company also implemented a restructuring plan to reduce operating costs and better align its workforce with the needs of its business. The plan resulted in a reduction of approximately 27% of the Company’s workforce.

In light of the recent situation affecting Silicon Valley Bank, N.A. (“SVB”), including the Federal Deposit Insurance Corporation takeover of SVB, the Company decided to move any cash or other deposits previously held at SVB to larger financial institutions. We have access to all of our cash and other deposits previously held at SVB. We do not anticipate any material impact on our financial condition or operations as a result of SVB’s circumstances.

Note 5 - Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Accrued compensation	$ 3,112	$ 2,786
Accrued clinical and manufacturing expenses	2,413	986
Accrued professional and consulting services	691	556
Accrued other expenses	1,868	736
Total	$ 8,084	$ 5,064

Note 11 - Equity Incentive Plans - Assumptions of Options (Details) - Share-Based Payment Arrangement, Option [Member]	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Minimum [Member]
Risk-free interest rate	1.62%	0.91%
Expected term (in years) (Year)	5 years 5 months 1 day	5 years 5 months 8 days
Expected volatility	125.00%	122.00%
Maximum [Member]
Risk-free interest rate	4.02%	1.35%
Expected term (in years) (Year)	6 years 29 days	6 years 29 days
Expected volatility	131.00%	131.00%

Note 13 - Income Taxes - Components of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Net operating loss carryforwards	$ 39,822	$ 30,256
Research and development tax credits	7,943	4,923
Capitalized research and development	14,260	4,016
Sale of future royalties	2,886	5,826
Lease liability	4,581	3,184
Accruals, reserves and other	5,004	3,043
Total deferred tax assets	74,496	51,248
Valuation allowance	(66,323)	(42,589)
Deferred tax assets net of valuation allowance	8,173	8,659
Intangible assets	(2,614)	(5,410)
Right-of-use assets	(5,427)	(3,223)
Depreciation on property and equipment	(132)	(26)
Total deferred tax liabilities	(8,173)	(8,659)
Net deferred tax assets	$ 0	$ 0

Note 13 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2022

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

	*Year Ended December 31,*
	*2022*		*2021*

Current:
Federal	$	—	$	—
State		3		1
Foreign		64		106

Total Current		67		107

Deferred:
Federal		—		—
State		—		—
Foreign		—		—

Total Deferred		—		—

Provision for income taxes	$	67	$	107

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	*December 31, 2022*			*December 31, 2021*
Deferred tax assets:
Net operating loss carryforwards	$	39,822		$	30,256
Research and development tax credits		7,943			4,923
Capitalized research and development		14,260			4,016
Sale of future royalties		2,886			5,826
Lease liability		4,581			3,184
Accruals, reserves and other		5,004			3,043
Total deferred tax assets		74,496			51,248
Valuation allowance		(66,323	)		(42,589	)
Deferred tax assets net of valuation allowance		8,173			8,659
Deferred tax liabilities:
Intangible assets		(2,614	)		(5,410	)
Right-of-use assets		(5,427	)		(3,223	)
Depreciation on property and equipment		(132	)		(26	)
Total deferred tax liabilities		(8,173	)		(8,659	)

Net deferred tax assets	$	—		$	—

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	*Year Ended December 31,*
	*2022*			*2021*

U.S. federal taxes at statutory rate		21.0	%		21.0	%
State taxes (net of federal benefit)		0.1			4.0
Foreign rate differential		(0.3	)		0.3
Permanently non-deductible items		(1.5	)		0.2
Tax credits		3.0			3.4
Change in valuation allowance		(22.0	)		(29.3	)
Tax attributes write-off due to change in control		—			—
Prior year true-up		(0.2	)		0.6
Other		(0.2	)		(0.3	)

Provision for income taxes		(0.1	)%		(0.1	)%

Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]

	*Year Ended December 31,*
	*2022*			*2021*

Beginning Balance	$	2,422		$	1,281
Additions based on tax positions related to the current year		2,589			1,132
Increase (decreases) related to prior years’ tax positions		(66	)		9

Ending Balance	$	4,945		$	2,422

Note 4 - Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2022

Fair Value Disclosures [Text Block]

NOTE 4. Fair Value of Financial Instruments

Fair value accounting is applied for all financial assets and liabilities and nonfinancial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis (at least annually). Financial instruments include cash and cash equivalents, marketable securities, accounts receivable, accounts payable and accrued liabilities that approximate fair value due to their relatively short maturities.

Assets and liabilities recorded at fair value on a recurring basis in the consolidated balance sheets are categorized based upon the level of judgment associated with inputs used to measure their fair values. The accounting guidance for fair value provides a framework for measuring fair value and requires certain disclosures about how fair value is determined. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The accounting guidance also establishes a three-level valuation hierarchy that prioritizes the inputs to valuation techniques used to measure fair value based upon whether such inputs are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect market assumptions made by the reporting entity.

The three-level hierarchy for the inputs to valuation techniques is briefly summarized as follows:

Level 1 – Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date;

Level 2 – Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and

Level 3 – Unobservable inputs that are significant to the measurement of the fair value of the assets or liabilities that are supported by little or no market data.

The following table sets forth the fair value of the Company’s financial assets that are measured on a recurring basis as of December 31, 2022 and 2021 (in thousands):

	*Level 1*		*Level 2*		*Level 3*		*Total*
December 31, 2022
Financial assets:
Money market funds	$	30,834	$	—	$	—	$	30,834
U.S. Treasury securities		—		41,542		—		41,542
Commercial paper		—		5,674		—		5,674
Corporate debt securities		—		2,488		—		2,488

Total assets	$	30,834	$	49,704	$	—	$	80,538

	*Level 1*		*Level 2*		*Level 3*		*Total*
December 31, 2021
Financial assets:
Money market funds	$	70,978	$	—	$	—	$	70,978
U.S. Treasury securities		—		24,997		—		24,997
Commercial paper		—		7,491		—		7,491
Corporate debt securities		—		6,464		—		6,464

Total assets	$	70,978	$	38,952	$	—	$	109,930

The Company held no financial liabilities measured on a recurring basis as of December 31, 2022 or 2021, or in the years ended December 31, 2022 and 2021.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Note 15 - Subsequent Events (Details Textual) - USD ($) $ in Thousands	2 Months Ended	12 Months Ended
	Mar. 08, 2023	Dec. 31, 2022	Dec. 31, 2021
Proceeds from Issuance of Common Stock		$ 17,237	$ 122,210
The September 2021 ATM [Member]
Stock Issued During Period, Shares, New Issues (in shares)		8,419,700
Proceeds from Issuance of Common Stock		$ 18,000
Subsequent Event [Member] \| The September 2021 ATM [Member]
Stock Issued During Period, Shares, New Issues (in shares)	1,362,220
Proceeds from Issuance of Common Stock	$ 1,500

Note 7 - Liabilities Related to Sale of Future Royalties (Tables)

12 Months Ended

Dec. 31, 2022

Deferred Revenue, by Arrangement, Disclosure [Table Text Block]

Total liability related to sale of future royalties, start of year	$	11,522
Non-cash royalty revenue paid to HCRP		(151	)
Non-cash interest expense recognized		1,305
Revaluation gain recognized		(6,960	)
Total liability related to sale of future royalties, end of year		5,716
Current portion		(95	)
Long-term portion	$	5,621

Note 10 - Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2022

Schedule of Common Stock Reserved for Issuance [Table Text Block]

	*December 31, 2022*		*December 31, 2021*

Options issued and outstanding		14,725,261		10,216,106
RSUs issued and outstanding		808,310		—
Available for future grants of equity awards		12,074,692		5,582,742
Common stock warrants		227,434		232,434
2022 Employee Stock Purchase Plan		1,800,000		—
Total		29,635,697		16,031,282

Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]

Securities into which warrants are convertible	Warrants outstanding		Exercise Price		Expiration Date

Common Stock		44,148	$	1.10	April 2024
Common Stock		26,515	$	1.375	April 2024
Common Stock		29,150	$	2.50	March 2025
Common Stock		100,532	$	3.125	February 2025
Common Stock		16,175	$	3.125	March 2024
Common Stock		10,914	$	22.99	December 2026
Total		227,434

Note 11 - Equity Incentive Plans

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement [Text Block]

NOTE 11. Equity Incentive Plans

On April 23, 2019, the Company’s stockholders approved the adoption of the 2019 Equity Incentive Plan (the “2019 Plan”), under which the Company is authorized to issue incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock awards, restricted stock units (RSUs), other stock awards and performance awards that may be settled in cash, stock, or other property. The 2019 Plan is designed to secure and retain the services of employees, directors and consultants, provide incentives for the Company’s employees, directors and consultants to exert maximum efforts for the success of the Company and its affiliates, and provide a means by which employees, directors and consultants may be given an opportunity to benefit from increases in the value of the Company’s common stock. Following adoption of the 2019 Plan, all previous plans were frozen, and on forfeiture, cancellation and expiration, awards under those plans are not assumed by the 2019 Plan.

The aggregate number of shares of common stock authorized for issuance under the 2019 Plan was initially 1,600,000 shares, which was increased through an amendment to the 2019 Plan adopted by the Company’s stockholders (a “Plan Amendment”) on June 8, 2020, to 8,000,000, by a Plan Amendment on June 16, 2021, to 16,900,000, and by a Plan Amendment on August 4, 2022, to 28,900,000. Further amendments to the 2019 Plan to increase the share reserve would require stockholder approval. Awards that are forfeited or canceled generally become available for issuance again under the 2019 Plan. Awards have a maximum term of ten years from the grant date and may vest over varying periods, as specified by the Company’s board of directors for each grant.

During the year ended December 31, 2022, the Company granted 850,061 RSUs awards to employees which vest annually over four years, subject to each employee’s continued service relationship with the Company, and 29,500 RSUs to directors which vest annually over three years and 35,717 RSUs to directors which vest on the earlier of the day before the next annual meeting of stockholders and the anniversary of the grant date, subject to each director’s continued service on the Board. The related compensation cost, which is based on the grant date fair value of the Company’s common stock multiplied by the number of RSUs granted, is recognized, net of estimated forfeitures, as an expense ratably over the service period.

A summary of stock option and RSU transactions in each of the two years ended December 31, 2022 and 2021 is as follows:

							*Weighted*					*Weighted*
	*Shares*			*Number of*			*Option Average*		*Number of*			*RSU Average*
	*Available*			*Options*			*Exercise*		*RSUs*			*Grant Date*
	*For Grant*			*Outstanding*			*Price*		*Outstanding*			*Fair Value*

Balance at January 1, 2021		1,230,863			6,813,033		$	2.70		—		$	—

Authorized under 2019 Plan Amendment		8,900,000			—		$	—		—		$	—
Granted		(5,178,438	)		5,178,438		$	7.09		—		$	—
Exercised		—			(1,070,921	)	$	1.63		—		$	—
Forfeited		630,317			(650,054	)	$	3.16		—		$	—
Canceled		—			(54,390	)	$	11.98		—		$	—

Balance at December 31, 2021		5,582,742			10,216,106		$	4.96		—		$	—

Authorized under 2019 Plan Amendment		12,000,000			—		$	—		—		$	—
Granted		(7,291,935	)		6,376,657		$	4.10		915,278		$	3.58
Exercised		—			(180,336	)	$	1.24		—		$	—
Forfeited		1,625,133			(1,518,230	)	$	6.19		(106,968	)	$	3.62
Canceled		158,752			(168,936	)	$	7.17		—		$	—

Balance at December 31, 2022		12,074,692			14,725,261		$	4.48		808,310		$	3.57

As of December 31, 2022, there were 14,725,261 options outstanding with a weighted average exercise price of $4.48, a weighted average remaining term of 6.60 years and an aggregate intrinsic value of $148,000. Of these options, 5,881,798 were vested, with a weighted average exercise price of $3.88, a weighted average remaining term of 5.35 years and an aggregate intrinsic value of $133,000.

The aggregate intrinsic value represents the total pre-tax value (i.e., the difference between the Company’s stock price and the exercise price) of stock options outstanding as of December 31, 2022, based on the Company’s common stock closing price of $0.96, which would have been received by the option holders had all their in-the-money options been exercised as of that date.

The Company received $223,000 for the 180,336 options exercised during the year ended December 31, 2022, which had an intrinsic value of $481,000, $1.7 million for the 1,070,921 options exercised during the year ended December 31, 2021, which had an intrinsic value of $6.2 million.

The weighted average grant date fair value of options awarded in the years ended December 31, 2022 and 2021, was $4.10 and $6.49, respectively. Fair values were estimated using the following assumptions:

	Year Ended December 31,
	2022			2021

Risk-free interest rate		1.62% - 4.02	%		0.91% - 1.35	%
Expected term (in years)		5.42 - 6.08			5.44 - 6.08
Expected volatility		125% - 131	%		122% - 131	%
Dividend yield		—	%		—	%

The Company measures the fair value of all stock-based awards on the grant date and records the fair value of these awards, net of estimated forfeitures, to compensation expense over the service period. Total stock-based compensation recognized for options was as follows (in thousands):

	*Year Ended December 31,*
	*2022*		*2021*

Research and development	$	9,183	$	4,304
General and administrative		4,404		4,563
Total stock-based compensation	$	13,587	$	8,867

Effective June 16, 2021, the Company modified the terms of outstanding options awarded to its former Chairman of the Board, Wouter W. Latour, such that the vesting of 100,000 options that would otherwise have been forfeited was accelerated. Further, the post-termination exercise period for all his vested and outstanding options as of the termination date was extended from three months to the earlier of the expiry of their ten-year term and June 16, 2023. The Company recorded a charge for the incremental increase in fair value of $1.3 million, which was included in stock-based compensation expense within general and administrative expenses in the three months ended June 30, 2021.

As of December 31, 2022, the unrecognized stock-based compensation cost related to outstanding stock options and RSUs expected to vest was $28.1 million, which the Company expects to recognize over an estimated weighted average period of 2.9 years.

On August 4, 2022, the 2022 Employee Stock Purchase Plan (the “2022 ESPP”) was approved by the Company’s stockholders. The Company reserved 1,800,000 shares of the Company’s common stock for purchase under the ESPP. The ESPP has a 6-month offering period comprised of one purchase period. The purchase price of the stock is equal to 85% of the lesser of the market value of such shares at the beginning of the 6-month offering period or the end of such offering period. No ESPP shares were issued or outstanding during the year ended December 31, 2022, accordingly 1,800,000 shares were available and reserved for issuance under the ESPP.

The fair value of the ESPP shares is estimated using the Black-Scholes option pricing model. The weighted average estimated fair value for shares issued under our ESPP in fiscal years 2022 was $0.46 per share, with the assumptions of 0.5 expected term (in years), 84.66% expected volatility, 4.60% risk-free interest rate, and 0% expected dividend yield. Stock-based compensation expense related to the ESPP for the year ended December 31, 2022 was nil.

Note 8 - Leases (Tables)

12 Months Ended

Dec. 31, 2022

Lessee, Operating Lease, Liability, Maturity [Table Text Block]

Year Ending December 31,	Amount
2023	$	4,072
2024		4,213
2025		4,356
2026		4,964
2027		5,138
Thereafter		6,649
Undiscounted total		29,392
Less: imputed interest		(7,687	)
Present value of future minimum payments		21,705
Current portion of operating lease liability		(2,228	)
Operating lease liability, net of current portion	$	19,477

Lease, Cost [Table Text Block]

	*Year Ended December 31,*
	*2022*		*2021*
Lease cost
Operating lease cost	$	4,159	$	2,513
Short-term lease cost		436		340
Variable lease cost		1,312		1,233
Sublease income		-		(36	)
Total lease cost	$	5,907	$	4,050

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balances (in shares) at Dec. 31, 2020	110,271,093
Balances at Dec. 31, 2020	$ 11	$ 272,274	$ (148,881)	$ 0	$ 123,404
Issuance of common stock (in shares)	13,239,839
Issuance of common stock	$ 2	122,208	0	0	122,210
Issuance of common stock upon exercise of common stock warrants (in shares)	1,012,540
Issuance of common stock upon exercise of common stock warrants	$ 0	1,849	0	0	$ 1,849
Issuance of common stock upon exercise of options (in shares)	1,070,921				1,070,921
Issuance of common stock upon exercise of options	$ 0	1,745	0	0	$ 1,745
Stock-based compensation	0	8,867	0	0	8,867
Unrealized gains (losses) on available-for-sale investments	0	0	0	(74)	(74)
Net loss	0	0	(70,470)	0	(70,470)
Issuance of common stock upon exercise of common stock warrants	$ 0	1,849	0	0	1,849
Balances (in shares) at Dec. 31, 2021	125,594,393
Balances at Dec. 31, 2021	$ 13	406,943	(219,351)	(74)	187,531
Issuance of common stock (in shares)	8,419,700
Issuance of common stock	$ 0	17,237	0	0	17,237
Issuance of common stock upon exercise of common stock warrants (in shares)	5,000
Issuance of common stock upon exercise of common stock warrants	$ 0	2	0	0	$ 2
Issuance of common stock upon exercise of options (in shares)	180,336				180,336
Issuance of common stock upon exercise of options	$ 0	223	0	0	$ 223
Stock-based compensation	0	13,587	0	0	13,587
Unrealized gains (losses) on available-for-sale investments	0	0	0	(225)	(225)
Net loss	0	0	(107,758)	0	(107,758)
Issuance of common stock upon exercise of common stock warrants	$ 0	2	0	0	2
Balances (in shares) at Dec. 31, 2022	134,199,429
Balances at Dec. 31, 2022	$ 13	$ 437,992	$ (327,109)	$ (299)	$ 110,597

Note 13 - Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Current:
Federal	$ 0	$ 0
State	3	1
Foreign	64	106
Total Current	67	107
Deferred:
Federal	0	0
State	0	0
Foreign	0	0
Total Deferred	0	0
Provision for income taxes	$ 67	$ 107

Note 7 - Liabilities Related to Sale of Future Royalties - Deferred Revenue Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Revaluation gain recognized	$ (7,000)	$ (3,800)
Current portion	(95)	(836)
Long-term portion	5,621	10,686
HealthCare Royalty Partners III, L.P. [Member] \| Royalty Arrangement [Member]
Total liability related to sale of future royalties, start of year	11,522
Non-cash royalty revenue paid to HCRP	(151)
Non-cash interest expense recognized	1,305
Revaluation gain recognized	(6,960)
Total liability related to sale of future royalties, end of year	5,716	$ 11,522
Current portion	(95)
Long-term portion	$ 5,621

Note 5 - Balance Sheet Components (Details Textual) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Accounts Receivable, after Allowance for Credit Loss, Current, Total		$ 20,000	$ 71,000
Accounts Receivable, Allowance for Credit Loss, Current		0
Depreciation, Total		1,967,000	732,000
Tangible Asset Impairment Charges, Total		0
Operating Lease, Right-of-Use Asset		25,715,000	13,168,000
Amortization of Intangible Assets		1,300,000	1,700,000
Goodwill, Ending Balance		4,508,000	4,508,000
Goodwill, Impairment Loss		$ 0
Developed Technology Rights [Member]
Finite-Lived Intangible Asset, Remaining Life (Year)		6 years 10 months 24 days
Impairment of Intangible Assets (Excluding Goodwill), Total		$ 4,300,000	$ 3,000,000.0
Intellectual Property [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	20 years		20 years
Finite-Lived Intangible Asset, Remaining Life (Year)		5 years
Maximum [Member] \| Developed Technology Rights [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	11 years 9 months		11 years 9 months
Facility in Burlingame, California [Member]
Operating Lease, Right-of-Use Asset	$ 15,000,000.0
Royalty [Member]
Accounts Receivable, after Allowance for Credit Loss, Current, Total		$ 20,000	$ 71,000

Note 14 - Net Loss Per Share Attributable to Common Stockholders (Tables)

12 Months Ended

Dec. 31, 2022

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	*Year Ended December 31,*
	*2022*			*2021*

Net loss	$	(107,758	)	$	(70,470	)

Shares used to compute net loss per share, basic and diluted		127,683,813			121,453,723

Net loss per share attributable to common stockholders, basic and diluted	$	(0.84	)	$	(0.58	)

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	*Year Ended December 31,*
	*2022*		*2021*

Options to purchase common stock	13,567,390			8,206,137
Restricted stock unit to purchase common stock		460,975		—
Warrants to purchase common stock	228,725			369,043
Employee Stock Purchase Plan		392,095		—

Total potentially dilutive securities excluded from denominator of the diluted earnings per share computation		14,649,185		8,575,180

Note 3 - Business Combination (Tables)

12 Months Ended

Dec. 31, 2022