Note 13 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Notes Tables

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

	Years ended December 31,
	2021			2020
Tax at federal statutory rate	$	(2,651	)	$	(3,151	)
State, net of federal benefit		—			(449	)
Research and development credit		(279	)		(276	)
Share-based compensation		264			649
PPP Note forgiveness		—			(107	)
Other		2			2
Change in valuation allowance		2,664			3,332
Total provision for income taxes	$	—		$	—

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

	Years ended December 31,
	2021			2020
Accrued compensation	$	191		$	225
Inventory adjustments		15			335
Depreciation and amortization		24			90
Share-based compensation		595			686
Net operating loss and tax credit carryforwards		30,277			26,931
Other		2			173
Gross Deferred Tax Asset		31,104			28,440
Valuation Allowance		(31,104	)		(28,440	)
Net deferred tax asset	$	—		$	—

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

	Years ended December 31,
	2021			2020
Balance, beginning of year	$	1,235		$	1,046
Additions based on tax positions related to the current year		158			189
Reductions for tax positions related to prior years		(25	)		—
Balance, end of year	$	1,368		$	1,235