Note 10 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Notes Tables

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

	December 31,
	2021		2020
Current
Federal	$	—	$	—
State		—		—
		—		—
Deferred
Federal	$	—	$	—
State		—		—
Total deferred tax expense		—		—
Total income tax expense	$	—	$	—

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

	December 31,
	2021			2020
Federal tax benefit at statutory rate		21	%		21	%
Change in valuation allowance		(21	)%		(12	)%
Section 382 limitation		—			—
Other non-deductible expenses		(1	)%		(1	)%
Stock based compensation					(8	)%
Other		1	%		—
Total		0	%		0	%

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

	December 31,
	2021			2020
Net operating loss carry forwards	$	18,205		$	10,988
Research and development tax credits		404			90
Stock based compensation and other		3,694			2,860
Operating lease obligation		1,339			1,789
Total deferred tax assets		23,642			15,727
Less: Valuation allowance		(23,179	)		(15,106	)
Deferred tax liabilities		—			—
Operating lease right-of-use assets		(463	)		(621	)
Net deferred tax assets	$	—		$	—

Summary of Income Tax Contingencies [Table Text Block]

	Amount
Balance at January 1, 2020		39
Gross increase/ (decrease) related to prior year tax positions		—
Gross increase related to current year positions		—
Reductions to unrecognized tax benefits related to lapsing statute of limitations		—
Balance at December 31, 2020	$	39
Gross increase/ (decrease) related to prior year tax positions		124
Gross increase related to current year positions		46
Reductions to unrecognized tax benefits related to lapsing statute of limitations		—
Balance at December 31, 2021	$	209