Note 3 - Cash and Investments - Schedule of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Cash	$ 2,092	$ 2,243
Cash equivalents (see detail in Note 4)	5,428	33,171
Restricted cash (see detail in Note 4)	221	221
Total cash, cash equivalents and restricted cash	7,741	35,635	$ 39,442	$ 40,087
Short-term investments	26,211	7
Total cash, cash equivalents, restricted cash and short-term investments	$ 33,952	$ 35,642