Note 11 - Income Taxes - Unrecognized Tax Positions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Beginning balance	$ 1,512	$ 1,363
Gross increases for tax positions related to current periods	108	149
Gross increases for tax positions related to prior periods	0	0
Ending balance	$ 1,620	$ 1,512