Note 11 - Income Taxes - Deferred Tax Asset (Liability) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net operating loss carryforwards	$ 17,734	$ 14,264
Stock options and warrants	1,090	1,151
Property and equipment	310	(46)
Property and equipment	310	(46)
Intangible assets	688	875
Capitalized expenses	105	117
Other	440	655
Operating right-of-use lease assets	0	0
Operating right-of-use lease liabilities	124	167
Net deferred tax assets	20,491	17,183
Less: Valuation allowance	(20,491)	(17,183)	$ (15,456)
Deferred tax asset (liability)	$ 0	$ 0