Note 3 - Cash and Investments - Schedule of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Cash	$ 2,063	$ 2,506
Cash equivalents (see detail in Note 4)	24,102	37,023
Restricted cash (see detail in Note 4)	221	557
Total cash, cash equivalents and restricted cash	26,386	40,086	$ 41,367	$ 12,960
Short-term investments	10,677	0
Total cash, cash equivalents, restricted cash and short-term investments	$ 37,063	$ 40,086