Note 12 - Summary of Stock Options - Stock-based Compensation Expense Included in the Statement of Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Stock-based compensation expense	$ 909	$ 867	$ 1,869	$ 1,677
Cost of Sales [Member]
Stock-based compensation expense	64	60	129	115
Research and Development Expense [Member]
Stock-based compensation expense	120	102	243	200
Selling, General and Administrative Expenses [Member]
Stock-based compensation expense	$ 725	$ 705	$ 1,497	$ 1,362