Note 9 - Share-based Compensation - Allocation of Share-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
Share-based expense	$ 1,221	$ 727	$ 1,849	$ 1,756
Selling, General and Administrative Expenses [Member]
Share-based expense	990	591	1,552	1,485
Research and Development Expense [Member]
Share-based expense	$ 231	$ 136	$ 297	$ 271