Note 11 - Income Taxes - Deferred Tax Asset (Liability) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net operating loss carryforwards	$ 14,264	$ 13,385
Stock options and warrants	1,151	832
Property and equipment	(46)	(16)
Intangible assets	875	950
Capitalized expenses	117	105
Other	655	64
Operating right-of-use lease assets	(478)	(566)
Operating right-of-use lease liabilities	645	670
Net deferred tax assets	17,183	15,456
Less: Valuation allowance	(17,183)	(15,456)	$ (12,421)
Deferred tax asset (liability)	$ 0	$ 0