Note 11 - Income Taxes - Reconciliation of Valuation Allowances (Details) - SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Balance	$ 20,321	$ 19,520	$ 18,190
Addition	15,405	1,743	1,560
Reduction	(718)	(942)	(230)
Balance	$ 35,008	$ 20,321	$ 19,520