Note 12 - Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Tax at federal statutory rate	$ (3,701)	$ (3,657)
State taxes, net of federal benefit	(916)	(711)
Permanent differences	(484)	(445)
Change in valuation allowance	5,084	5,104
Research credits	(273)	(286)
Nondeductible interest expense	290	0
Other	0	(5)
Provision for taxes	$ 0	$ 0