Note 6 - Stockholders' Equity and Stock-based Compensation - Stock-based Compensation Expense by Recorded Location (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Total stock-based compensation expense	$ 5,191	$ 14,601	$ 10,075
Cost of Sales [Member]
Total stock-based compensation expense	217	129	0
Research and Development Expense [Member]
Total stock-based compensation expense	1,563	5,211	4,013
Selling and Marketing Expense [Member]
Total stock-based compensation expense	733	2,749	1,187
General and Administrative Expense [Member]
Total stock-based compensation expense	$ 2,678	$ 6,512	$ 4,875