0001437749-21-011133 | 10-Q | XBRL Viewer

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Document And Entity Information - shares	3 Months Ended
Document And Entity Information - shares	Mar. 31, 2021	May 05, 2021
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	Q1
Document Fiscal Year Focus	2021
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		122,268,453

Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 157,311	$ 126,870
Short-term investments	13,385	0
Accounts receivable	700	334
Prepaid expenses and other current assets	4,024	1,327
Total current assets	175,420	128,531
Long-term investments	6,554	0
Property and equipment, net	2,245	1,480
Right-of-use assets, net	6,350	6,838
Intangible assets, net	14,928	15,361
Other long-term assets	369	372
Total assets	205,866	152,582
Current liabilities:
Accounts payable	4,638	2,133
Current portion of operating lease liability	2,006	2,052
Liability related to sale of future royalties, current portion	1,822	2,779
Other accrued liabilities	3,176	4,799
Total current liabilities	11,642	11,763
Operating lease liability, net of current portion	4,628	5,156
Liability related to sale of future royalties, net of current portion	13,239	12,150
Other long-term liabilities	122	109
Total liabilities	29,631	29,178
Commitments and contingencies (Note 8)
Stockholders’ equity:
Preferred stock: $0.0001 par value; 5,000,000 shares authorized; none issued and outstanding as of March 31, 2021 and December 31, 2020	0	0
Common stock: $0.0001 par value; 150,000,000 shares authorized; 117,963,912 and 110,271,093 shares issued and outstanding as of March 31, 2021 and December 31, 2020, respectively	12	11
Additional paid-in capital	341,116	272,274
Accumulated deficit	(164,888)	(148,881)
Accumulated other comprehensive loss	(5)	0
Total stockholders’ equity	176,235	123,404
Total liabilities and stockholders’ equity	$ 205,866	$ 152,582

Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - $ / shares	Mar. 31, 2021	Dec. 31, 2020
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)	150,000,000	150,000,000
Common stock, shares issued (in shares)	117,963,912	110,271,093
Common stock, shares outstanding (in shares)	117,963,912	110,271,093

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue:
Revenue	$ 506,000	$ 2,902,000
Operating expenses:
Research and development	10,073,000	1,542,000
General and administrative	5,944,000	1,990,000
Restructuring costs	0	64,000
Total operating expenses	16,017,000	3,596,000
Operating loss	(15,511,000)	(694,000)
Other income and (expenses):
Interest income	9,000	41,000
Non-cash interest expense related to sale of future royalties	(466,000)	(491,000)
Foreign exchange loss, net	(1,000)	0
Loss before income taxes	(15,969,000)	(1,144,000)
Provision for income taxes	38,000	153,000
Net loss	$ (16,007,000)	$ (1,297,000)
Net loss per share - basic and diluted (in dollars per share)	$ (0.14)	$ (0.02)
Shares used to compute net loss per share - basic and diluted (in shares)	115,422,628	60,677,145
Comprehensive loss:
Net loss	$ (16,007,000)	$ (1,297,000)
Unrealized loss on available-for-sale investments	(5,000)	0
Comprehensive loss	(16,012,000)	(1,297,000)
Customer Service Contracts [Member]
Revenue:
Revenue	13,000	99,000
Royalty [Member]
Revenue:
Revenue	0	2,769,000
Non Cash Royalty Revenue [Member]
Revenue:
Revenue	$ 493,000	$ 34,000

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	The September 2019 Offering [Member] Common Stock [Member]	The September 2019 Offering [Member] Additional Paid-in Capital [Member]	The September 2019 Offering [Member] Retained Earnings [Member]	The September 2019 Offering [Member]	The October 2020 Offering [Member] Common Stock [Member]	The October 2020 Offering [Member] Additional Paid-in Capital [Member]	The October 2020 Offering [Member] Retained Earnings [Member]	The October 2020 Offering [Member] AOCI Attributable to Parent [Member]	The October 2020 Offering [Member]	Placement Agents' Designees [Member] Common Stock [Member]	Placement Agents' Designees [Member] Additional Paid-in Capital [Member]	Placement Agents' Designees [Member] Retained Earnings [Member]	Placement Agents' Designees [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balances (in shares) at Dec. 31, 2019														48,254,994
Balances at Dec. 31, 2019														$ 5	$ 129,608	$ (116,661)		$ 12,952
Issuance of common stock upon exercise of common stock warrants (in shares)														19,726,120
Issuance of common stock upon exercise of common stock warrants														$ 2	10,347	0		$ 10,349
Issuance of common stock upon exercise of stock options (in shares)														23,606				23,606
Issuance of common stock upon exercise of stock options														$ 0	18	0		$ 18
Stock-based compensation														0	96	0		96
Net loss														$ 0	0	(1,297)		(1,297)
Issuance of common stock, pre-funded warrants and common stock warrants, net of offering costs (in shares)	4,000,000
Issuance of common stock, pre-funded warrants and common stock warrants, net of offering costs	$ 0	$ 8,722	$ 0	$ 8,722
Issuance of common stock warrants to placement agents’ designees										$ 0	$ 453	$ 0	$ 453
Balances (in shares) at Mar. 31, 2020														72,004,720
Balances at Mar. 31, 2020														$ 7	149,244	(117,958)		31,293
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)					6,654,367
Issuance of common stock					$ 1	$ 65,711	$ 0	$ 0	$ 65,712
Issuance of common stock upon exercise of common stock warrants (in shares)														830,722
Issuance of common stock upon exercise of common stock warrants														$ 0	1,649	0	0	$ 1,649
Issuance of common stock upon exercise of stock options (in shares)														207,730				207,730
Issuance of common stock upon exercise of stock options														$ 0	231	0	0	$ 231
Stock-based compensation														0	1,251	0	0	1,251
Unrealized loss on available-for-sale investments														0	0	0	(5)	(5)
Net loss														$ 0	0	(16,007)	0	(16,007)
Balances (in shares) at Mar. 31, 2021														117,963,912
Balances at Mar. 31, 2021														$ 12	$ 341,116	$ (164,888)	$ (5)	$ 176,235

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) (Parentheticals) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
The September 2019 Offering [Member]
Offering costs from issuance of common stock and warrants		$ 1,278
The October 2020 Offering [Member]
Offering costs	$ 3,182

Condensed Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net loss	$ (16,007,000)	$ (1,297,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	996,000	580,000
Stock-based compensation	1,251,000	96,000
Non-cash interest expense related to sale of future royalties	466,000	491,000
Non-cash revenue related to sale of future royalties	(334,000)	(2,769,000)
Change in operating assets and liabilities:
Accounts receivable	(366,000)	956,000
Prepaid expenses and other assets	(2,694,000)	(690,000)
Accounts payable	2,281,000	(55,000)
Other accrued liabilities	(2,185,000)	(520,000)
Net cash used in operating activities	(16,592,000)	(3,208,000)
Cash flows from investing activities:
Purchase of property and equipment	(615,000)	(4,000)
Proceeds from sale of equipment	0	3,000
Purchases of investments	(19,944,000)	0
Net cash used in investing activities	(20,559,000)	(1,000)
Cash flows from financing activities:
Proceeds from issuance of common stock upon exercise of common stock warrants	1,649,000	10,349,000
Proceeds from issuance of common stock upon exercise of stock options	231,000	18,000
Net cash provided by financing activities	67,592,000	19,542,000
Net increase in cash and cash equivalents	30,441,000	16,333,000
Cash and cash equivalents at beginning of the period	126,870,000	13,526,000
Cash and cash equivalents at end of the period	157,311,000	29,859,000
Supplemental disclosure of non-cash financing activity:
Issuance of warrants to placement agent’s representatives	0	453,000
Acquisition of property and equipment included in accounts payable and accrued expenses	303,000	0
Registered Direct Offering [Member]
Cash flows from financing activities:
Net proceeds from issuance of common stock	0	9,175,000
ATM Program [Member]
Cash flows from financing activities:
Net proceeds from issuance of common stock	$ 65,712,000	$ 0

Note 1 - Organization and Basis of Presentation

3 Months Ended

Mar. 31, 2021

Notes to Financial Statements

Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]

NOTE 1. Organization and Basis of Presentation

General

Vaxart Biosciences, Inc. was originally incorporated in California in March 2004, under the name West Coast Biologicals, Inc. The Company changed its name to Vaxart, Inc. (“Private Vaxart”) in July 2007, and reincorporated in the state of Delaware.

On February 13, 2018, Private Vaxart completed a business combination with Aviragen Therapeutics, Inc. (“Aviragen”), pursuant to which Aviragen merged with Private Vaxart, with Private Vaxart surviving as a wholly owned subsidiary of Aviragen (the “Merger”). Pursuant to the terms of the Merger, Aviragen changed its name to Vaxart, Inc. (together with its subsidiaries, the “Company” or “Vaxart”) and Private Vaxart changed its name to Vaxart Biosciences, Inc.

On June 8, 2020, the Company’s shareholders approved an amendment to the Company’s certificate of incorporation to change the par value of its common and preferred stock from $0.10 per share to $0.0001 per share and to increase the number of authorized shares of common stock from 100,000,000 to 150,000,000. Except as otherwise noted in these condensed consolidated financial statements, all share, equity security and per share amounts are presented to give retroactive effect to these changes.

On October 13, 2020, the Company entered into the Open Market Sale Agreement, (the “Sales Agreement”) pursuant to which it may offer and sell, from time to time through sales agents, shares of its common stock having an aggregate offering price of up to $250 million. The Company incurred direct expenses of approximately $0.3 million in connection with filing a prospectus supplement, dated October 13, 2020, with the U.S. Securities and Exchange Commission (the “SEC”), and will pay sales commissions of 4.5% of gross proceeds from the sale of shares. As of December 31, 2020, the Company had sold 692,651 shares for gross proceeds of $5.5 million which, after deducting sales commissions and expenses, resulted in net proceeds under the Sales Agreement of $4.9 million in 2020.

In the three months ended March 31, 2021, the Company sold an additional 6,654,367 shares for gross proceeds of $68.9 million which, after deducting sales commissions and expenses, resulted in net proceeds to date under the Sales Agreement of $65.7 million. A total of 7,347,018 shares have been issued under the Sales Agreement since its inception for gross proceeds of $74.4 million which, after deducting sales commissions and expenses, has resulted in net proceeds of $70.6 million.

The Company’s principal operations are based in South San Francisco, California, and it operates in one reportable segment, which is the discovery and development of oral recombinant protein vaccines, based on its proprietary oral vaccine platform.

Note 2 - Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2021

Notes to Financial Statements

Significant Accounting Policies [Text Block]

NOTE 2. Summary of Significant Accounting Policies

Basis of Presentation – The Company has prepared the accompanying condensed consolidated financial statements pursuant to the rules and regulations of the SEC. Certain information and footnote disclosures normally included in consolidated financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) have been condensed or omitted pursuant to these rules and regulations. These condensed consolidated financial statements should be read in conjunction with the Company’s audited financial statements and footnotes related thereto for the year ended December 31, 2020, included in the Company’s Annual Report on Form 10-K filed with the SEC on February 25, 2021 (the “Annual Report”). Except as noted below, there have been no material changes to the Company’s significant accounting policies described in Note 2 to the consolidated financial statements included in the Annual Report. In the opinion of management, the unaudited condensed consolidated financial statements include all adjustments (consisting only of normal recurring adjustments) necessary to present fairly the Company’s financial position and the results of its operations and cash flows. The results of operations for such interim periods are not necessarily indicative of the results to be expected for the full year.

Basis of Consolidation – The condensed 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 – 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, 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.

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 and (expenses). 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 and (expenses). 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 condensed 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 condensed 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 of Credit Risk – Financial instruments that potentially subject the Company to significant concentrations of credit risk consist principally of cash, cash equivalents, available-for-sale investments and accounts receivable. The Company places its cash, cash equivalents 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 and cash equivalents to the extent such amounts are in excess of the federally insured limits. The Company has not experienced any losses on its deposits since inception.

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. The Company generally requires no collateral from its customers.

Recent Accounting Pronouncements

In August 2020, the FASB issued Accounting Standards Update (ASU) 2020-06, Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in an Entity’s Own Equity (Subtopic 815-40). In addition to simplifying the accounting for certain debt and equity instruments, none of which the Company presently has outstanding, this standard update provides guidance on how certain instruments should be treated in the computation of earnings per share. The Company adopted the new guidance effective January 1, 2021, using the modified retrospective method. Its adoption has an immaterial impact on the number of shares used in the computation of year-to-date basic and diluted earnings per share.

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

Note 3 - Fair Value of Financial Instruments

3 Months Ended

Mar. 31, 2021

Notes to Financial Statements

Fair Value Disclosures [Text Block]

NOTE 3. 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 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 March 31, 2021 (in thousands):

	*Level 1*		*Level 2*		*Level 3*		*Total*
Money market funds	$	83,124	$	—	$	—	$	83,124
U.S. Treasury securities		—		4,997		—		4,997
Commercial paper		—		8,388		—		8,388
Corporate debt securities		—		6,554		—		6,554
Total	$	83,124	$	19,939	$	—	$	103,063

As of December 31, 2020, the Company held money market funds of $60,005,000, classified as Level 1 and included in cash and cash equivalents in the condensed consolidated balance sheet. The Company held no recurring financial liabilities as of March 31, 2021 or December 31, 2020, or in the three months ended March 31, 2021 or 2020.

- Definition

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 4 - Balance Sheet Components

3 Months Ended

Mar. 31, 2021

Notes to Financial Statements

Supplemental Balance Sheet Disclosures [Text Block]

NOTE 4. Balance Sheet Components

(a)

Cash, Cash Equivalents and Investments

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

	*March 31, 2021*
	*Amortized*		*Gross Unrealized*					*Estimated*		*Cash and Cash*		*Short-Term*		*Long-Term*
	*Cost*		*Gains*		*Losses*			*Fair Value*		*Equivalents*		*Investments*		*Investments*

Cash at banks	$	74,187	$	—	$	—		$	74,187	$	74,187	$	—	$	—
Money market funds		83,124		—		—			83,124		83,124		—		—
U.S. Treasury securities		4,998		—		(1	)		4,997		—		4,997		—
Commercial paper		8,388		—		—			8,388		—		8,388		—
Corporate debt securities		6,558		—		(4	)		6,554						6,554
Total	$	177,255	$	—	$	(5	)	$	177,250	$	157,311	$	13,385	$	6,554

As of December 31, 2020, the Company held cash at banks of $66,865,000, money market funds of $60,005,000 and no investments in marketable securities.

(b)

Accounts Receivable

Accounts receivable comprises the following (in thousands):

	*March 31, 2021*		*December 31, 2020*

Royalties receivable	$	468	$	334
Customer service contracts - billed		232		—
Accounts receivable	$	700	$	334

The Company has provided no allowance for uncollectible accounts as of March 31, 2021 and December 31, 2020.

(c)

Property and Equipment, Net

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

	*March 31, 2021*			*December 31, 2020*

Laboratory equipment	$	2,072		$	1,759
Office and computer equipment		302			294
Construction in progress		519			—
Total property and equipment		2,893			2,053
Less: accumulated depreciation		(648	)		(573	)
Property and equipment, net	$	2,245		$	1,480

Depreciation expense was $75,000 and $19,000 for the three months ended March 31, 2021 and 2020, respectively. There were no impairments of the Company’s property and equipment recorded in the three months ended March 31, 2021 or 2020.

(d)

Right-of-Use Assets, Net

Right-of-use assets, net consists of the following (in thousands):

	*March 31, 2021*		*December 31, 2020*

Facilities	$	6,348	$	6,836
Office equipment		2		2
Right-of-use assets, net	$	6,350	$	6,838

(e)

Intangible Assets, Net

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 lives ranging from 1.3 to 11.75 years for developed technology and 20 years for intellectual property. As of March 31, 2021, developed technology and intellectual property had remaining lives of 8.6 and 6.75 years, respectively. Intangible assets consist of the following (in thousands):

	*March 31, 2021*			*December 31, 2020*

Purchased technology	$	20,300		$	20,300
Intellectual property		80			80
Total cost		20,380			20,380
Less: accumulated amortization		(5,452	)		(5,019	)
Intangible assets, net	$	14,928		$	15,361

Total amortization expense for the three months ended March 31, 2021 and 2020, was $433,000 and $433,000, respectively.

As of March 31, 2021, the estimated future amortization expense by year is as follows (in thousands):

Year Ending December 31,	Amount
2021 (nine months remaining)	$	1,299
2022		1,731
2023		1,732
2024		1,732
2025		1,731
Thereafter		6,703
Total	$	14,928

(f)

Other Accrued Liabilities

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

	*March 31, 2021*		*December 31, 2020*

Accrued compensation	$	1,044	$	1,618
Accrued clinical and manufacturing expenses		889		1,772
Accrued professional and consulting services		906		777
Other liabilities, current portion		337		632
Total	$	3,176	$	4,799

Note 5 - Revenue

3 Months Ended

Mar. 31, 2021

Notes to Financial Statements

Revenue [Text Block]

NOTE 5. Revenue

Service Contracts with Customers

Contract Balances. Accounts receivable related to service contracts with customers as of March 31, 2021 and December 31, 2020, was $232,000 and nil, respectively. Contract assets, representing unbilled receivables where revenue has been recognized in advance of customer billings, as of March 31, 2021 and December 31, 2020, was nil and $219,000, respectively, which is included in prepaid expenses and other current assets.

Remaining Performance Obligations. Remaining Performance Obligations (“RPO”) comprise deferred revenue plus unbilled contract revenue. As of March 31, 2021 and December 31, 2020, there was no deferred revenue and the aggregate amount of RPO was nil and $13,000, respectively, all of which was unbilled contract revenue which is not recorded on the balance sheet. Unbilled contract revenue represents non-cancelable contracts under which the Company has an obligation to perform, for which revenue has not yet been recognized in the financial statements and the fixed amounts billable have not yet been invoiced.

Royalty Agreements

Aviragen entered into a royalty-generating research and license agreement with GlaxoSmithKline, plc (“GSK”) in 1990 for the development and commercialization of zanamivir, a neuraminidase inhibitor marketed by GSK as Relenza, to treat influenza. All of the Company’s Relenza patents have expired, with the last remaining patent expiring in July 2019 in Japan, at which time royalty revenue ceased, although until April 30, 2020, it remained subject to adjustments for sales returns and exchange rate differences. There was no royalty revenue related to Relenza recognized in the three months ended March 31, 2021 or 2020.

The Company also 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, at which time royalty revenue will cease. The royalty revenue related to Inavirrecognized in the three months ended March 31, 2021 and 2020, was nil and $2,769,000, respectively, representing 4% of net sales in Japan. In addition, the Company recognized non-cash royalty revenue related to the sale of future royalties (see Note 6) of $493,000 and $34,000 in the three months ended March 31, 2021 and 2020, 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 $25,000 and $140,000 was included in income tax expense in the three months ended March 31, 2021 and 2020, respectively.

The Company’s royalty revenue is seasonal, in line with the flu season, so the majority of the Company’s royalty revenue is earned in the first and fourth fiscal quarters.

Note 8 - Commitments and Contingencies

3 Months Ended

Mar. 31, 2021

Notes to Financial Statements

Commitments and Contingencies Disclosure [Text Block]

NOTE 8. Commitments and Contingencies

(a)

Purchase Commitments

As of March 31, 2021, the Company had approximately $26.8 million of non-cancelable purchase commitments, principally for contract manufacturing and clinical services which are expected to be paid within the next eighteen months. In addition, the Company has operating lease commitments as detailed in Note 7.

(b)

Indemnifications

In the ordinary course of business, the Company enters into agreements that may include indemnification provisions. Pursuant to such agreements, the Company may indemnify, hold harmless and defend indemnified parties for losses suffered or incurred by the indemnified party. Some of the provisions will limit losses to those arising from third-party actions. In some cases, the indemnification will continue after the termination of the agreement. The maximum potential amount of future payments the Company could be required to make under these provisions is not determinable. The Company has also entered into indemnification agreements with its directors and officers that require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers to the fullest extent permitted by Delaware corporate law. The Company currently has directors’ and officers’ insurance.

(c)

Litigation

From time to time the Company may be involved in legal proceedings arising in connection with its business. Based on information currently available, the Company believes that the amount, or range, of reasonably possible losses in connection with any pending actions against it in excess of established reserves, in the aggregate, is not material to its consolidated financial condition or cash flows. However, any current or future dispute resolution or legal proceeding, regardless of the merits of any such proceeding, could result in substantial costs and a diversion of management’s attention and resources that are needed to run the Company successfully, and could have a material adverse impact on its business, financial condition and results of operations.

On August 4, 2020, a purported shareholder derivative complaint was filed in the Superior Court of California, San Mateo County, entitled Godfrey v. Latour, et al. An amended complaint was filed on September 4, 2020, and the case was re-named Ennis v. Latour, et al. A second amended complaint was filed on November 25, 2020. The second amended complaint names certain of Vaxart’s officers and directors as defendants, asserting claims against them for breach of fiduciary duty, unjust enrichment, and waste and seeking, among other things, an award of unspecified damages, certain equitable relief, and attorneys’ fees and costs. The complaint also asserts claims for breach of fiduciary duty, unjust enrichment, and aiding and abetting breach of fiduciary duty against Armistice Capital, LLC (“Armistice”). The claims challenge certain stock options granted to certain of the Company’s officers and directors between March 24, 2020 and June 15, 2020 and certain amendments to two warrants held by Armistice, as disclosed on June 8, 2020. The second amended complaint purports to bring the lawsuit derivatively on behalf of and for the benefit of the Company and names the Company as a “nominal defendant” against which no damages are sought. On December 30, 2020, all defendants in the action filed a demurrer with the court addressing the second amended complaint, seeking to have the entire case dismissed. On March 15, 2021, the court sustained the demurrer, dismissing the complaint in its entirety, without prejudice to file a newly-amended complaint.

On September 8, 2020, a purported shareholder derivative complaint was filed in the Chancery Court in the State of Delaware, entitled Galjour v. Floroiu, et al. On October 20, 2020, a purported shareholder derivative and class action complaint, entitled Jaquith v. Vaxart, Inc., was filed in the Court of Chancery of the State of Delaware. The complaints name as defendants certain of Vaxart’s current and former directors, asserting claims against them for breach of fiduciary duty, unjust enrichment, and waste and seeking, among other things, an award of unspecified damages, certain equitable relief, and attorneys’ fees and costs. The complaints also assert claims against Armistice. The complaints challenge certain stock options granted to certain of the Company’s officers and directors between March 24, 2020 and June 15, 2020 and certain amendments made to two warrants held by Armistice, as disclosed on June 8, 2020. Both complaints purport to bring suit derivatively on behalf of and for the benefit of the Company, and the Jaquith complaint also purports to assert a direct claim for breach of fiduciary duty on behalf of a class of Vaxart stockholders. Both complaints name the Company as a “nominal defendant” against which no claims are asserted and no damages are sought. On October 9, 2020, all defendants moved to dismiss the Galjour complaint and to stay the action pending disposition of the Ennis action in California. On November 12, 2020, the Galjour and Jaquith actions were consolidated under the caption In re Vaxart, Inc. Stockholder Litigation and the complaint filed in the Jaquith v. Latour action was deemed the operative pleading. On January 4, 2021, all defendants filed motions to dismiss, seeking to have the case dismissed. Those motions remain pending.

On September 17, 2020, a purported derivative complaint was filed in the U.S. District Court for the Northern District of California, entitled Stachowski v. Boyd, et al. The complaint names as defendants certain of Vaxart’s current directors, asserting claims against them for breach of fiduciary duty and unjust enrichment and seeking, among other things, an award of unspecified damages, certain equitable relief, and attorneys’ fees and costs. The complaint also alleges a violation of §14(a) of the Securities Exchange Act of 1934 for allegedly false statements or omissions in the Company’s April 24, 2020, proxy statement regarding the Company’s options practices. The complaint also asserts a claim for breach of fiduciary duty against Armistice. The claims are based on allegations that certain stock options granted to certain of the Company’s officers and directors between March 24, 2020 and June 15, 2020, were allegedly improper and that certain warrants held by Armistice were amended on June 8, 2020, allegedly for no consideration. The complaint purports to bring the lawsuit derivatively on behalf of and for the benefit of the Company and names the Company as a “nominal defendant” against which no claims are asserted and no damages are sought. On November 13, 2020, plaintiffs voluntarily withdrew their claims and the case was dismissed.

Two substantially similar securities class actions were filed in the U.S. District Court for the Northern District of California, the first, titled Himmelberg v. Vaxart, Inc. et al. was filed on August 24, 2020 (the “Himmelberg Action”), and the second action, titled Hovhannisyan v. Vaxart, Inc. et al. was filed on September 1, 2020 (the “Hovhannisyan Action,” and together, the “Putative Class Actions”). On September 17, 2020, the court issued an order that the Putative Class Actions were related and would proceed as one consolidated action. On December 9, 2020, the court appointed the lead plaintiffs and lead plaintiffs’ counsel and on January 29, 2021, the lead plaintiffs filed their consolidated amended complaint. The consolidated amended complaint names as defendants certain of Vaxart’s current and former executive officers and directors, and Armistice. It claims two violations of federal civil securities laws, violation of SEC Rule 10b-5, as against all defendants; violation of Section 20(a) of the Exchange Act, as against all defendants except for Vaxart; and violation of Section 20A of the Exchange Act against Armistice. The consolidated amended complaint alleges that the defendants violated securities laws by misstating and omitting information regarding the Company’s development of a norovirus vaccine, the vaccine manufacturing capabilities of a business counterparty, as well as the Company’s Operation Warp Speed (“OWS”) involvement to deceive the investing public and inflate Vaxart’s stock price. The consolidated amended complaint seeks to be certified as a class action for similarly situated shareholders and seek, among other things, an uncertain amount of damages and attorneys’ fees and costs. Defendants have filed motions to dismiss the consolidated amended complaint, which is pending.

On October 23, 2020, a purported shareholder derivative complaint was filed in the U.S. District Court for the Southern District of New York, entitled Roth v. Armistice Capital LLC, et al. The complaint names Armistice and an Armistice-affiliated Company director as defendants, asserting a violation of Exchange Act Section 16(b) and seeking the disgorgement of short-swing profits obtained in violation thereof. The complaint purports to bring the lawsuit derivatively on behalf of and for the benefit of the Company and names the Company as a “nominal defendant” against which no damages are sought.

On January 8, 2021, a purported shareholder, Phillip Chan, commenced a pro se lawsuit in the U.S. District Court for the Northern District of California titled Chan v. Vaxart, Inc. et al. (the “Opt-Out Action”). This complaint is nearly identical to an earlier version of the complaint filed in the Putative Class Actions, naming the same defendants, certain of Vaxart’s current and former executive officers and directors and Armistice, and asserting identical legal claims relating to the same factual allegations. The complaint asserts two violations of federal civil securities laws, violation of Section 10(b) of the Exchange Act and SEC Rule 10b-5, as against all defendants, and violation of Section 20(a) of the Exchange Act, as against the individual defendants. The Opt-Out Action alleges that the defendants violated securities laws by misstating and omitting information regarding the Company’s development of a Covid-19 vaccine as well as its OWS involvement to deceive the investing public and inflate Vaxart’s stock price. The Opt-Out Action has been stayed pending resolution of the Putative Class Actions.

On February 4, 2021, a purported shareholder, Stephen Barker, commenced a lawsuit in the Delaware Court of Chancery titled Barker v. Vaxart, Inc. et al. The complaint names as defendants the Company and its current board of directors. The complaint asserts a single claim for declaratory relief seeking a declaration that one of the Company’s bylaws, which requires a supermajority vote to remove a Company director from office, is in violation of Delaware General Corporate Law Section 141(k). It does not seek damages.

On March 5, 2021, a purported shareholder, Kathleen Sanetel, served a demand letter on the Company’s board of directors demanding that it investigate and commence appropriate legal action against certain members of the board of directors and/or executive officers, and Armistice to remedy purportedly wrongful conduct beginning in April 2020. The specific allegations and alleged wrongful conduct set forth in the demand letter are, in all material respects, substantially similar to the allegations and claims made in the consolidated amended complaint in the Putative Class Actions. After receipt of the demand letter, the Board appointed a committee of the Board (the “Demand Committee”) and delegated to the Demand Committee the authority to investigate the matters referenced in the demand letter and determine action(s), if any, to be taken by the Company in response to the demand.

The Company’s legal costs incurred in its defense against these claims are expensed as incurred.

Note 9 - Stockholders' Equity

3 Months Ended

Mar. 31, 2021

Notes to Financial Statements

Stockholders' Equity Note Disclosure [Text Block]

NOTE 9. 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 the Company’s 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

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 March 31, 2021, 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 of 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:

	*March 31, 2021*		*December 31, 2020*

Options issued and outstanding		7,764,164		6,813,033
Available for future grants of equity awards		67,863		1,230,863
Common stock warrants		414,252		1,244,974
Total		8,246,279		9,288,870

(c)

Warrants

The following warrants were outstanding as of March 31, 2021, 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		5,000	$	0.30	September 2024
Common Stock		225,966	$	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		414,252

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 $0.30, $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 warrantholders 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.

Note 10 - Equity Incentive Plans

3 Months Ended

Mar. 31, 2021

Notes to Financial Statements

Share-based Payment Arrangement [Text Block]

NOTE 10. 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 and restricted stock units, 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 on June 8, 2020, to 8,000,000 (the “Plan Amendment”). Further amendments to the 2019 Plan to increase the share reserve would require stockholder approval. Awards that expire or are 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.

A summary of stock option transactions in the three months ended March 31, 2021, is as follows:

							*Weighted*
	*Shares*			*Number of*			*Average*
	*Available*			*Options*			*Exercise*
	*For Grant*			*Outstanding*			*Price*

Balance at January 1, 2021		1,230,863			6,813,033		$	2.70
Granted		(1,163,000	)		1,163,000		$	6.27
Exercised		—			(207,730	)	$	1.11
Canceled		—			(4,139	)	$	5.17

Balance at March 31, 2021		67,863			7,764,164		$	3.28

As of March 31, 2021, there were 7,764,164 options outstanding with a weighted average exercise price of $3.28, a weighted average remaining term of 8.91 years and an aggregate intrinsic value of $23.5 million. Of these options, 3,007,780 were vested, with a weighted average exercise price of $2.65, a weighted average remaining term of 8.48 years and an aggregate intrinsic value of $11.3 million. The Company received $231,000 for the 207,730 options exercised during the three months ended March 31, 2021, which had an intrinsic value of $1.1 million, and received $18,000 for the 23,606 options exercised during the three months ended March 31, 2020, which had an intrinsic value of $25,000.

The weighted average grant date fair value of options awarded in the three months ended March 31, 2021, was $5.46. Their fair values were estimated using the following assumptions:

Risk-free interest rate		1.02% - 1.07%
Expected term	5.87 - 6.07 Years
Expected volatility		122% - 124%
Dividend yield		—	%

No options were awarded in the three months ended March 31, 2020. 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:

	*Three Months Ended March 31,*
	*2021*		*2020*

Research and development	$	579	$	22
General and administrative		672		74
Total stock-based compensation	$	1,251	$	96

As of March 31, 2021, the unrecognized stock-based compensation cost related to outstanding unvested stock options was $13.3 million, which the Company expects to recognize over an estimated weighted average period of 2.55 years.

Note 11 - Net Loss Per Share

3 Months Ended

Mar. 31, 2021

Notes to Financial Statements

Earnings Per Share [Text Block]

NOTE 11. Net Loss Per Share

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

	*Three Months Ended March 31,*
	*2021*			*2020*

Net loss	$	(16,007	)	$	(1,297	)

Shares used to compute net loss per share – basic and diluted		115,422,628			60,677,145

Net loss per share – basic and diluted	$	(0.14	)	$	(0.02	)

No adjustment has been made to the net loss in the three months ended March 31, 2021 or 2020, as the effect would be anti-dilutive due to the net loss.

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

	*Three Months Ended March 31,*
	*2021*		*2020*

Options to purchase common stock		6,834,510		1,773,779

Performance-based restricted stock units		—		36,132

Warrants to purchase common stock		622,942		33,023,381

Total potentially dilutive securities excluded from denominator of the diluted earnings per share computation		7,457,452		34,833,292

Note 12 - Subsequent Events

3 Months Ended

Mar. 31, 2021

Notes to Financial Statements

Subsequent Events [Text Block]

NOTE 12. Subsequent Events

Since March 31, 2021, the Company has issued 4,304,541 shares of common stock under the Sales Agreement (see Note 1) for net proceeds totaling $36.3 million.

Significant Accounting Policies (Policies)	3 Months Ended
Significant Accounting Policies (Policies)	Mar. 31, 2021
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation – The Company has prepared the accompanying condensed consolidated financial statements pursuant to the rules and regulations of the SEC. Certain information and footnote disclosures normally included in consolidated financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) have been condensed or omitted pursuant to these rules and regulations. These condensed consolidated financial statements should be read in conjunction with the Company’s audited financial statements and footnotes related thereto for the year ended December 31, 2020, included in the Company’s Annual Report on Form 10-K filed with the SEC on February 25, 2021 (the “Annual Report”). Except as noted below, there have been no material changes to the Company’s significant accounting policies described in Note 2 to the consolidated financial statements included in the Annual Report. In the opinion of management, the unaudited condensed consolidated financial statements include all adjustments (consisting only of normal recurring adjustments) necessary to present fairly the Company’s financial position and the results of its operations and cash flows. The results of operations for such interim periods are not necessarily indicative of the results to be expected for the full year.
Consolidation, Policy [Policy Text Block]	Basis of Consolidation – The condensed 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, 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.
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 and (expenses). 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 and (expenses). 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 condensed 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 condensed 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, available-for-sale investments and accounts receivable. The Company places its cash, cash equivalents 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 and cash equivalents to the extent such amounts are in excess of the federally insured limits. The Company has not experienced any losses on its deposits since inception. 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. The Company generally requires no collateral from its customers.
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements In August 2020, the FASB issued Accounting Standards Update (ASU) 2020-06, Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in an Entity’s Own Equity (Subtopic 815-40). In addition to simplifying the accounting for certain debt and equity instruments, none of which the Company presently has outstanding, this standard update provides guidance on how certain instruments should be treated in the computation of earnings per share. The Company adopted the new guidance effective January 1, 2021, using the modified retrospective method. Its adoption has an immaterial impact on the number of shares used in the computation of year-to-date basic and diluted earnings per share. The Company has reviewed all other significant newly-issued accounting pronouncements that are not yet effective and concluded that they are either not applicable to its operations or their adoption is not expected to have a material impact on its financial position or results of operations.

Note 3 - Fair Value of Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2021

Notes Tables

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

	*Level 1*		*Level 2*		*Level 3*		*Total*
Money market funds	$	83,124	$	—	$	—	$	83,124
U.S. Treasury securities		—		4,997		—		4,997
Commercial paper		—		8,388		—		8,388
Corporate debt securities		—		6,554		—		6,554
Total	$	83,124	$	19,939	$	—	$	103,063

Note 4 - Balance Sheet Components (Tables)

3 Months Ended

Mar. 31, 2021

Notes Tables

Cash, Cash Equivalents and Investments [Table Text Block]

	*March 31, 2021*
	*Amortized*		*Gross Unrealized*					*Estimated*		*Cash and Cash*		*Short-Term*		*Long-Term*
	*Cost*		*Gains*		*Losses*			*Fair Value*		*Equivalents*		*Investments*		*Investments*

Cash at banks	$	74,187	$	—	$	—		$	74,187	$	74,187	$	—	$	—
Money market funds		83,124		—		—			83,124		83,124		—		—
U.S. Treasury securities		4,998		—		(1	)		4,997		—		4,997		—
Commercial paper		8,388		—		—			8,388		—		8,388		—
Corporate debt securities		6,558		—		(4	)		6,554						6,554
Total	$	177,255	$	—	$	(5	)	$	177,250	$	157,311	$	13,385	$	6,554

Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]

	*March 31, 2021*		*December 31, 2020*

Royalties receivable	$	468	$	334
Customer service contracts - billed		232		—
Accounts receivable	$	700	$	334

Property, Plant and Equipment [Table Text Block]

	*March 31, 2021*			*December 31, 2020*

Laboratory equipment	$	2,072		$	1,759
Office and computer equipment		302			294
Construction in progress		519			—
Total property and equipment		2,893			2,053
Less: accumulated depreciation		(648	)		(573	)
Property and equipment, net	$	2,245		$	1,480

Lessee, Operating Lease, Right-of-Use Assets [Table Text Block]

	*March 31, 2021*		*December 31, 2020*

Facilities	$	6,348	$	6,836
Office equipment		2		2
Right-of-use assets, net	$	6,350	$	6,838

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

	*March 31, 2021*			*December 31, 2020*

Purchased technology	$	20,300		$	20,300
Intellectual property		80			80
Total cost		20,380			20,380
Less: accumulated amortization		(5,452	)		(5,019	)
Intangible assets, net	$	14,928		$	15,361

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

Year Ending December 31,	Amount
2021 (nine months remaining)	$	1,299
2022		1,731
2023		1,732
2024		1,732
2025		1,731
Thereafter		6,703
Total	$	14,928

Schedule of Accrued Liabilities [Table Text Block]

	*March 31, 2021*		*December 31, 2020*

Accrued compensation	$	1,044	$	1,618
Accrued clinical and manufacturing expenses		889		1,772
Accrued professional and consulting services		906		777
Other liabilities, current portion		337		632
Total	$	3,176	$	4,799

Note 6 - Liabilities Related to Sale of Future Royalties (Tables)

3 Months Ended

Mar. 31, 2021

Notes Tables

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

Total liability related to sale of future royalties, start of period	$	14,929
Non-cash royalty revenue paid to HCRP		(334	)
Non-cash interest expense recognized		466
Total liability related to sale of future royalties, end of period		15,061
Current portion		(1,822	)
Long-term portion	$	13,239

Note 7 - Leases (Tables)

3 Months Ended

Mar. 31, 2021

Notes Tables

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

Year Ending December 31,
2021 (nine months remaining)	$	1,887
2022		1,801
2023		1,585
2024		1,641
2025		1,112
Undiscounted total		8,026
Less: imputed interest		(1,392	)
Present value of future minimum payments		6,634
Current portion of operating lease liability		(2,006	)
Operating lease liability, net of current portion	$	4,628

Lease, Cost [Table Text Block]

	*Three Months Ended March 31,*
	*2021*			*2020*
Lease cost
Operating lease cost	$	662		$	189
Short-term lease cost		60			3
Variable lease cost		293			11
Sublease income		(36	)		(54	)
Total lease cost	$	979		$	149

Note 9 - Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2021

Notes Tables

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

	*March 31, 2021*		*December 31, 2020*

Options issued and outstanding		7,764,164		6,813,033
Available for future grants of equity awards		67,863		1,230,863
Common stock warrants		414,252		1,244,974
Total		8,246,279		9,288,870

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		5,000	$	0.30	September 2024
Common Stock		225,966	$	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		414,252

Note 10 - Equity Incentive Plans (Tables)

3 Months Ended

Mar. 31, 2021

Notes Tables

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

							*Weighted*
	*Shares*			*Number of*			*Average*
	*Available*			*Options*			*Exercise*
	*For Grant*			*Outstanding*			*Price*

Balance at January 1, 2021		1,230,863			6,813,033		$	2.70
Granted		(1,163,000	)		1,163,000		$	6.27
Exercised		—			(207,730	)	$	1.11
Canceled		—			(4,139	)	$	5.17

Balance at March 31, 2021		67,863			7,764,164		$	3.28

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

Risk-free interest rate		1.02% - 1.07%
Expected term	5.87 - 6.07 Years
Expected volatility		122% - 124%
Dividend yield		—	%

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

	*Three Months Ended March 31,*
	*2021*		*2020*

Research and development	$	579	$	22
General and administrative		672		74
Total stock-based compensation	$	1,251	$	96

Note 11 - Net Loss Per Share (Tables)

3 Months Ended

Mar. 31, 2021

Notes Tables

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

	*Three Months Ended March 31,*
	*2021*			*2020*

Net loss	$	(16,007	)	$	(1,297	)

Shares used to compute net loss per share – basic and diluted		115,422,628			60,677,145

Net loss per share – basic and diluted	$	(0.14	)	$	(0.02	)

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

	*Three Months Ended March 31,*
	*2021*		*2020*

Options to purchase common stock		6,834,510		1,773,779

Performance-based restricted stock units		—		36,132

Warrants to purchase common stock		622,942		33,023,381

Total potentially dilutive securities excluded from denominator of the diluted earnings per share computation		7,457,452		34,833,292

Note 1 - Organization and Basis of Presentation (Details Textual) $ / shares in Units, $ in Millions		3 Months Ended		6 Months Ended
	Oct. 13, 2020 USD ($)	Mar. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Mar. 31, 2021 USD ($) $ / shares shares	Jun. 08, 2020 $ / shares shares	Jun. 07, 2020 shares	Apr. 11, 2019 $ / shares
Common Stock, Par or Stated Value Per Share (in dollars per share) \| $ / shares		$ 0.0001	$ 0.0001	$ 0.0001	$ 0.0001
Common Stock, Shares Authorized (in shares) \| shares		150,000,000	150,000,000	150,000,000	150,000,000	100,000,000
Number of Operating Segments		1
Open Market Sale Agreement [Member]
Open Market Sale Agreement, Maximum Aggregate Offering Price	$ 250.0
Payments of Stock Issuance Costs	$ 0.3
Open Market Sale Agreement, Sales Commission, Percentage	4.50%
Stock Issued During Period, Shares, New Issues (in shares) \| shares		6,654,367	692,651	7,347,018
Proceeds from Issuance of Common Stock		$ 68.9	$ 5.5	$ 74.4
Proceeds from Issuance of Common Stock, Net		$ 65.7	$ 4.9	$ 70.6
Warrants in Connection With the April 2019 Offering [Member]
Pre-funded Warrant, Accompanying Warrant, Amount Paid Per Share (in dollars per share) \| $ / shares							$ 0.10

Note 3 - Fair Value of Financial Instruments (Details Textual) - USD ($)	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
Fair Value, Recurring [Member]
Financial Liabilities Fair Value Disclosure, Total	$ 0	$ 0	$ 0
Money Market Funds [Member]
Cash and Cash Equivalents, Fair Value Disclosure	83,124,000
Money Market Funds [Member] \| Fair Value, Recurring [Member]
Cash and Cash Equivalents, Fair Value Disclosure	$ 83,124,000	$ 60,005,000

Note 3 - Fair Value of Financial Instruments - Financial Assets Measured on a Recurring Basis (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Money Market Funds [Member]
Money market funds, Fair Value	$ 83,124,000
Fair Value, Recurring [Member]
Assets, Fair Value	103,063,000
Fair Value, Recurring [Member] \| Short-term Investments [Member] \| US Treasury Securities [Member]
Investments, Fair Value Disclosure	4,997,000
Fair Value, Recurring [Member] \| Short-term Investments [Member] \| Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Investments, Fair Value Disclosure	8,388,000
Fair Value, Recurring [Member] \| Long-term Investments [Member] \| Corporate Debt Securities [Member]
Investments, Fair Value Disclosure	6,554,000
Fair Value, Recurring [Member] \| Money Market Funds [Member]
Money market funds, Fair Value	83,124,000	$ 60,005,000
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value	83,124,000
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Short-term Investments [Member] \| US Treasury Securities [Member]
Investments, Fair Value Disclosure	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Short-term Investments [Member] \| Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Investments, Fair Value Disclosure	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Long-term Investments [Member] \| Corporate Debt Securities [Member]
Investments, Fair Value Disclosure	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Money Market Funds [Member]
Money market funds, Fair Value	83,124,000
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value	19,939,000
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Short-term Investments [Member] \| US Treasury Securities [Member]
Investments, Fair Value Disclosure	4,997,000
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Short-term Investments [Member] \| Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Investments, Fair Value Disclosure	8,388,000
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Long-term Investments [Member] \| Corporate Debt Securities [Member]
Investments, Fair Value Disclosure	6,554,000
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Money Market Funds [Member]
Money market funds, Fair Value	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Short-term Investments [Member] \| US Treasury Securities [Member]
Investments, Fair Value Disclosure	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Short-term Investments [Member] \| Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Investments, Fair Value Disclosure	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Long-term Investments [Member] \| Corporate Debt Securities [Member]
Investments, Fair Value Disclosure	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Money Market Funds [Member]
Money market funds, Fair Value	$ 0

Note 4 - Balance Sheet Components (Details Textual) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Cash, Ending Balance			$ 66,865,000
Money Market Funds, at Carrying Value			60,005,000
Marketable Securities, Total			0
Accounts Receivable, Allowance for Credit Loss, Current	$ 0		$ 0
Depreciation, Total	75,000	$ 19,000
Impairment of Property and Equipment	0	0
Amortization of Intangible Assets, Total	$ 433,000	$ 433,000
Developed Technology Rights [Member]
Finite-Lived Intangible Asset, Remaining Life (Year)	8 years 7 months 6 days
Intellectual Property [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	20 years
Finite-Lived Intangible Asset, Remaining Life (Year)	6 years 9 months
Minimum [Member] \| Developed Technology Rights [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	1 year 3 months 18 days
Maximum [Member] \| Developed Technology Rights [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	11 years 9 months

Note 4 - Balance Sheet Components - Cash and Cash Equivalents and Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Cash and cash equivalents	$ 157,311	$ 126,870	$ 29,859	$ 13,526
Gross Unrealized Loss	(5)
Short-term investments	13,385	0
Long-term investments	6,554	$ 0
Investments and Cash	177,255
Investments and Cash, Fair Value Disclosure	177,250
US Treasury Securities [Member]
Amortized Cost	4,998
Gross Unrealized Loss	(1)
Estimated Fair Value	4,997
Short-term investments	4,997
Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Amortized Cost	8,388
Estimated Fair Value	8,388
Short-term investments	8,388
Corporate Debt Securities [Member]
Amortized Cost	6,558
Gross Unrealized Loss	(4)
Estimated Fair Value	6,554
Long-term investments	6,554
Cash [Member]
Cash and Cash Equivalents, at Carrying Value	74,187
Money market funds, Fair Value	74,187
Cash and cash equivalents	74,187
Money Market Funds [Member]
Cash and Cash Equivalents, at Carrying Value	83,124
Money market funds, Fair Value	83,124
Cash and cash equivalents	$ 83,124

Note 4 - Balance Sheet Components - Accounts Receivable, Net of Allowance (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accounts receivable	$ 700	$ 334
Royalty [Member]
Accounts receivable	468	334
Customer Service Contracts [Member]
Accounts receivable	$ 232	$ 0

Note 4 - Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Property and equipment, gross	$ 2,893	$ 2,053
Less: accumulated depreciation	(648)	(573)
Property and equipment, net	2,245	1,480
Laboratory Equipment [Member]
Property and equipment, gross	2,072	1,759
Office Equipment [Member]
Property and equipment, gross	302	294
Construction in Progress [Member]
Property and equipment, gross	$ 519	$ 0

Note 4 - Balance Sheet Components - Right-of-use Assets, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Right-of-use assets, net	$ 6,350	$ 6,838
Facilities [Member]
Right-of-use assets, net	6,348	6,836
Office Equipment [Member]
Right-of-use assets, net	$ 2	$ 2

Note 4 - Balance Sheet Components - Intangible assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Intangible assets, gross	$ 20,380	$ 20,380
Less: accumulated amortization	(5,452)	(5,019)
Intangible assets, net	14,928	15,361
Purchased Technology [Member]
Intangible assets, gross	20,300	20,300
Intellectual Property [Member]
Intangible assets, gross	$ 80	$ 80

Note 4 - Balance Sheet Components - Estimated Future Amortization Expense (Details) $ in Thousands	Mar. 31, 2021 USD ($)
2021 (nine months remaining)	$ 1,299
2022	1,731
2023	1,732
2024	1,732
2025	1,731
Thereafter	6,703
Total	$ 14,928

Note 4 - Balance Sheet Components - Accrued liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accrued compensation	$ 1,044	$ 1,618
Accrued clinical and manufacturing expenses	889	1,772
Accrued professional and consulting services	906	777
Other liabilities, current portion	337	632
Total	$ 3,176	$ 4,799

Note 5 - Revenue (Details Textual) - USD ($)	3 Months Ended
Note 5 - Revenue (Details Textual) - USD ($)	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Contract with Customer, Asset, after Allowance for Credit Loss, Current, Total	$ 232,000		$ 0
Contract With Customer, Asset, Revenue Recognized	0		219,000
Contract with Customer, Liability, Total	0		0
Revenue, Remaining Performance Obligation, Amount	0		$ 13,000
Revenue from Contract with Customer, Including Assessed Tax	506,000	$ 2,902,000
Income Tax Expense (Benefit), Total	$ 38,000	153,000
Foreign Tax Authority [Member] \| National Tax Agency, Japan [Member]
Royalty Withholding Tax	5.00%
Income Tax Expense (Benefit), Total	$ 25,000	140,000
Royalty [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 0	2,769,000
Royalty [Member] \| Daiichi Sankyo Collaberation and License Agreement [Member]
Royalty Percentage	4.00%
Revenue from Contract with Customer, Including Assessed Tax	$ 0	2,769,000
Non Cash Royalty Revenue [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 493,000	$ 34,000

Note 6 - Liabilities Related to Sale of Future Royalties (Details Textual) - HCRP [Member] $ in Millions	1 Months Ended
	Apr. 30, 2016 USD ($)
Proceeds from Sale of Future Royalties, Net	$ 20
Royalty Interest Due Each Year	$ 3
Royalty Interest, Percentage of Additional Royalties Due Each Year	15.00%
Royalty Interest, Additional Royalties Due Each Year	$ 1

Note 6 - Liabilities Related to Sale of Future Royalties - Deferred Revenue Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Current portion	$ (1,822)	$ (2,779)
Long-term portion	13,239	$ 12,150
HealthCare Royalty Partners III, L.P. [Member] \| Royalty Arrangement [Member]
Total liability related to sale of future royalties, start of period	14,929
Non-cash royalty revenue paid to HCRP	(334)
Non-cash interest expense recognized	466
Total liability related to sale of future royalties, end of period	15,061
Current portion	(1,822)
Long-term portion	$ 13,239

Note 7 - Leases (Details Textual)	3 Months Ended
Note 7 - Leases (Details Textual)	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)
Lessee, Operating Lease, Number of Right-of-Use Leases	5
Lessee, Operating Lease, Number of Right-of-Use Leases, Subleased	1
Lessee, Operating Lease, Renewal Term (Year)	5 years
Operating Lease, Weighted Average Discount Rate, Percent	9.92%
Operating Lease, Weighted Average Remaining Lease Term (Year)	3 years 11 months 15 days
Lessee, Finance Lease, Number of Leases	0
Short-term Lease Commitment, Amount	$ 0
Operating Lease, Payments	$ 934,000	$ 237,000

Note 7 - Leases - Lease Liabilities Payment Obligations (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
2021 (nine months remaining)	$ 1,887
2022	1,801
2023	1,585
2024	1,641
2025	1,112
Undiscounted total	8,026
Less: imputed interest	(1,392)
Present value of future minimum payments	6,634
Current portion of operating lease liability	(2,006)	$ (2,052)
Operating lease liability, net of current portion	$ 4,628	$ 5,156

Note 7 - Leases - Operating Lease Expenses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating lease cost	$ 662	$ 189
Short-term lease cost	60	3
Variable lease cost	293	11
Sublease income	(36)	(54)
Total lease cost	$ 979	$ 149

Note 8 - Commitments and Contingencies (Details Textual) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($)
Purchase Obligation, Total	$ 26.8
Long-term Purchase Commitment, Period (Month)	18 months

Note 9 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
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
Dividends, Total	$ 0
First Set of Warrants Expiring September 2024 [Member]
Warrant Exercise Price to be Entitled to Receive Cash Consideration, Fundamental Transaction (in dollars per share)	$ 0.30
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 9 - Stockholders' Equity - Shares of Common Stock Reserved for Issuance (Details) - shares	Mar. 31, 2021	Dec. 31, 2020
Common stock reserved for issuance (in shares)	8,246,279	9,288,870
Options Issued and Outstanding [Member]
Common stock reserved for issuance (in shares)	7,764,164	6,813,033
Options Available for Future Grants [Member]
Common stock reserved for issuance (in shares)	67,863	1,230,863
Common Warrants [Member]
Common stock reserved for issuance (in shares)	414,252	1,244,974

Note 9 - Stockholders' Equity - Summary of Warrants Outstanding (Details)	Mar. 31, 2021 $ / shares shares
Warrants outstanding (in shares)	414,252
First Set of Warrants Expiring September 2024 [Member]
Warrants outstanding (in shares)	5,000
Exercise Price (in dollars per share) \| $ / shares	$ 0.30
First Set of Warrants Expiring April 2024 [Member]
Warrants outstanding (in shares)	225,966
Exercise Price (in dollars per share) \| $ / shares	$ 1.10
Second Set of Warrants Expiring April 2024 [Member]
Warrants outstanding (in shares)	26,515
Exercise Price (in dollars per share) \| $ / shares	$ 1.375
Warrants Expiring March 2025 [Member]
Warrants outstanding (in shares)	29,150
Exercise Price (in dollars per share) \| $ / shares	$ 2.50
Warrants Expiring February 2025 [Member]
Warrants outstanding (in shares)	100,532
Exercise Price (in dollars per share) \| $ / shares	$ 3.125
Warrants Expiring March 2024 [Member]
Warrants outstanding (in shares)	16,175
Exercise Price (in dollars per share) \| $ / shares	$ 3.125
Warrants Expiring December 2026 [Member]
Warrants outstanding (in shares)	10,914
Exercise Price (in dollars per share) \| $ / shares	$ 22.99

Note 10 - Equity Incentive Plans (Details Textual) - USD ($)		3 Months Ended
	Apr. 23, 2019	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Jun. 08, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)		7,764,164		6,813,033
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)		$ 3.28		$ 2.70
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)		8 years 10 months 28 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value		$ 23,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number (in shares)		3,007,780
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price (in dollars per share)		$ 2.65
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term (Year)		8 years 5 months 23 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value		$ 11,300,000
Proceeds from Stock Options Exercised		$ 231,000	$ 18,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)		207,730	23,606
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value		$ 1,100,000	$ 25,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)		1,163,000
Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)		$ 5.46
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)			0
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount		$ 13,300,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)		2 years 6 months 18 days
The 2019 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)	1,600,000				8,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)	10 years

Note 10 - Equity Incentive Plans - Summary of Stock Option Transactions (Details) - $ / shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Shares available for grant, balance (in shares)	1,230,863
Number of options outstanding, beginning balance (in shares)	6,813,033
Weighted average exercise price, balance (in dollars per share)	$ 2.70
Shares available for grant, granted (in shares)	(1,163,000)
Number of options outstanding, granted (in shares)	1,163,000
Weighted average exercise price, granted (in dollars per share)	$ 6.27
Number of options outstanding, exercised (in shares)	(207,730)	(23,606)
Weighted average exercise price, exercised (in dollars per share)	$ 1.11
Shares available for grant, canceled (in shares)	0
Number of options outstanding, canceled (in shares)	(4,139)
Weighted average exercise price, canceled (in dollars per share)	$ 5.17
Shares available for grant, balance (in shares)	67,863
Number of options outstanding, balance (in shares)	7,764,164
Weighted average exercise price, balance (in dollars per share)	$ 3.28

Note 10 - Equity Incentive Plans - Assumptions of Options (Details) - Share-based Payment Arrangement, Option [Member]	3 Months Ended
	Mar. 31, 2021
Dividend yield	0.00%
Minimum [Member]
Risk-free interest rate	1.02%
Expected term (Year)	5 years 10 months 13 days
Expected volatility	122.00%
Maximum [Member]
Risk-free interest rate	1.07%
Expected term (Year)	6 years 25 days
Expected volatility	124.00%

Note 10 - Equity Incentive Plans - Total Stock-based Compensation Recognized for Options (Details) - Share-based Payment Arrangement, Option [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Stock-based compensation	$ 1,251	$ 96
Research and Development Expense [Member]
Stock-based compensation	579	22
General and Administrative Expense [Member]
Stock-based compensation	$ 672	$ 74

Note 11 - Net Loss Per Share (Details Textual) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)
Dilutive Securities, Effect on Basic Earnings Per Share, Total	$ 0

Note 11 - Net Loss Per Share - Calculation of Basic and Diluted Net (Loss) Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net loss	$ (16,007)	$ (1,297)
Shares used to compute net loss per share - basic and diluted (in shares)	115,422,628	60,677,145
Net loss per share - basic and diluted (in dollars per share)	$ (0.14)	$ (0.02)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121641772&loc=SL7669619-108580

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8924-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
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+ Details

Note 11 - Net Loss Per Share - Summary of Antidilutive Securities (Details) - shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	7,457,452	34,833,292
Share-based Payment Arrangement, Option [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	6,834,510	1,773,779
Performance-based Restricted Stock Units (PRSUs) [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	0	36,132
Warrant [Member] \| Common Stock [Member]
Potentially dilutive securities excluded from denominator of the diluted earnings per share computation (in shares)	622,942	33,023,381

Note 12 - Subsequent Events (Details Textual) - Open Market Sale Agreement [Member] - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	May 05, 2021	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2021
Stock Issued During Period, Shares, New Issues (in shares)		6,654,367	692,651	7,347,018
Proceeds from Issuance of Common Stock		$ 68.9	$ 5.5	$ 74.4
Subsequent Event [Member]
Stock Issued During Period, Shares, New Issues (in shares)	4,304,541
Proceeds from Issuance of Common Stock	$ 36.3