Note 13 - Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Tax at federal statutory rate	$ (2,651)	$ (3,151)
State, net of federal benefit	0	(449)
Research and development credit	(279)	(276)
Share-based compensation	264	649
PPP Note forgiveness	0	(107)
Other	2	2
Change in valuation allowance	2,664	3,332
Total provision for income taxes	$ 0	$ 0