Note 6 - Stockholders' Equity and Stock-based Compensation - Stock-based Compensation Expense by Recorded Location (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Total stock-based compensation expense	$ 896	$ 2,007
Cost of Sales [Member]
Total stock-based compensation expense	0	90
Research and Development Expense [Member]
Total stock-based compensation expense	258	457
Selling and Marketing Expense [Member]
Total stock-based compensation expense	0	454
General and Administrative Expense [Member]
Total stock-based compensation expense	$ 638	$ 1,006