Note 2 - Summary of Significant Accounting Policies - Components of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Cash and cash equivalents	$ 10,508	$ 11,952
Restricted cash included in other assets	475	475
Total cash, cash equivalents, and restricted cash in the condensed consolidated statements of cash flows	$ 10,983	$ 12,427	$ 6,183	$ 7,412