Note 2 - Significant Accounting Policies - Share-based Compensation Expense (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
---|---|---|---|---|
Sep. 30, 2024 |
Sep. 30, 2023 |
Sep. 30, 2024 |
Sep. 30, 2023 |
|
Share-based compensation expense | $ 365 | $ 955 | $ 1,125 | $ 2,574 |
Research and Development Expense [Member] | ||||
Share-based compensation expense | 242 | 824 | 738 | 2,235 |
General and Administrative Expense [Member] | ||||
Share-based compensation expense | $ 123 | $ 131 | $ 387 | $ 339 |