Note 3 - Cash and Investments - Schedule of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash	$ 2,243	$ 2,506
Cash equivalents (see detail in Note 4)	33,171	37,023
Restricted cash (see detail in Note 4)	221	557
Total cash, cash equivalents and restricted cash	35,635	40,086	$ 12,960
Short-term investments	7	0
Total cash, cash equivalents, restricted cash and short-term investments	$ 35,642	$ 40,086