Note 7 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Notes Tables

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

	Year Ended December 31,
	2021		2020
Current expense (benefit):
Federal	$	—	$	—
State		—		—
Foreign		—		—
Current income tax benefit		—		—
Deferred expense (benefit):
Federal		—		—
State		—		—
Foreign		—		—
Deferred income tax expense		—		—
Total	$	—	$	—

Summary of Valuation Allowance [Table Text Block]

	Year Ended December 31,
	2021		2020
Valuation allowance at beginning of period	$	13,867	$	9,418
Income tax benefit		4,956		4,449
Release of valuation allowance		—		—
Valuation allowance at end of period	$	18,823	$	13,867

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

	Year Ended December 31,
	2021						2020
	Amount			Percent			Amount			Percent
Federal tax benefit at statutory rate	$	3,338			21.0	%	$	3,645			21.0	%
State tax benefit net of federal		25			0.2	%		44			0.3	%
Foreign rate differential		7			0.0	%		6			0.0	%
Stock warrant costs		1,413			8.9	%		493			2.8	%
Other permanent differences		(77	)		(0.5	)%		(63	)		(0.4	)%
Permanent provision to return items		344			2.2	%		361			2.1	%
Stock compensation change		(37	)		(0.2	)%		12			0.1	%
Uncertain tax provision		(57	)		(0.4	)%		(48	)		(0.3	)%
Other		—			—	%		(1	)		—	%
Increase in valuation allowance		(4,956	)		(31.2	)%		(4,449	)		(25.6	)%
Total tax (expense) benefit	$	—			—	%	$	—			—	%

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

	Year Ended December 31,
	2021			2020
Deferred tax assets:
Start-up costs	$	5,618		$	4,158
Federal net operating loss carryforwards		10,866			7,982
State tax loss carryforwards		64			48
Foreign net operating loss carryforwards		122			126
Tax credit carryforward		991			670
ROU Liability		34			58
Deferred compensation		1,157			880
Total deferred tax assets	$	18,852		$	13,922
Less valuation allowance		(18,823	)		(13,867	)
Net deferred tax assets	$	29		$	55
Deferred tax liabilities:
Fixed assets	$	(6	)	$	(12	)
ROU Asset		(23	)		(43	)
Total deferred tax liabilities	$	(29	)	$	(55	)
Net deferred taxes	$	—		$	—

Summary of Income Tax Contingencies [Table Text Block]

	Year Ended December 31,
	2021		2020
Balance, beginning of year	$	118	$	72
Additions for tax positions related to the current year		—		—
Additions for tax positions related to prior years		57		46
Reductions due to lapse of statutes of limitations		—		—
Decreases related to settlements with tax authorities		—		—
Balance, end of year	$	175	$	118