Note 12 - Stockholders' Equity - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Stock-based compensation expense	$ 599	$ 534	$ 1,286	$ 1,139
Cost of Sales [Member]
Stock-based compensation expense	18	23	47	48
Research and Development Expense [Member]
Stock-based compensation expense	22	18	40	36
General and Administrative Expense [Member]
Stock-based compensation expense	$ 559	$ 493	$ 1,199	$ 1,055