Note 2 - Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2023

Notes Tables

Schedule of Product Warranty Liability [Table Text Block]

	Three Months Ended March 31,
	2023		2022
Beginning balance	$	50	$	80
Add: Accruals for warranties issued during the period		—		17
Less: Adjustment for inventory at cost and excessive and obsolete inventory		—		—
Ending balance	$	50	$	97

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

	Three Months Ended March 31,
	2023		2022
Common stock warrants		7,208,193		—
Common stock options		5,608,210		5,558,884
Total		12,816,403		5,558,884