Note 12 - Summary of Stock Options - Stock-based Compensation Expense Included in the Statement of Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Stock-based compensation expense	$ 960	$ 810
Cost of Sales [Member]
Stock-based compensation expense	65	55
Research and Development Expense [Member]
Stock-based compensation expense	123	97
Selling, General and Administrative Expenses [Member]
Stock-based compensation expense	$ 772	$ 658