Note 3 - Cash and Investments - Schedule of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Cash	$ 1,212	$ 2,243
Cash equivalents (see detail in Note 4)	12,101	33,171
Restricted cash (see detail in Note 4)	221	221
Total cash, cash equivalents and restricted cash	13,534	35,635	$ 37,846	$ 40,087
Short-term investments	19,831	7
Total cash, cash equivalents, restricted cash and short-term investments	$ 33,365	$ 35,642