Note 14 - Stock Based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Stock compensation expense	$ 1,771	$ 1,214	$ 3,577	$ 1,854
General and Administrative Expense [Member]
Stock compensation expense	1,140	853	2,323	1,303
Research and Development Expense [Member]
Stock compensation expense	$ 631	$ 361	$ 1,254	$ 551