Note 9 - Share-based Compensation - Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Stock-based compensation	$ 1,313	$ 1,186	$ 3,915	$ 3,489
Share-Based Payment Arrangement, Option [Member]
Stock-based compensation	676	614	2,009	1,840
Restricted Stock Units (RSUs) [Member]
Stock-based compensation	481	432	1,443	1,231
Performance-based Restricted Units [Member]
Stock-based compensation	$ 156	$ 140	$ 463	$ 418