Note 11 - Benefit Plans - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Total stock-based compensation expense | $ 1,367 | $ 1,951 | $ 3,314 | $ 3,964 |
| Share-Based Payment Arrangement, Option [Member] | ||||
| Total stock-based compensation expense | 1,496 | 1,951 | 3,443 | 3,953 |
| Restricted Stock Awards [Member] | ||||
| Total stock-based compensation expense | (129) | 0 | (129) | 11 |
| General and Administrative Expense [Member] | ||||
| Total stock-based compensation expense | 767 | 1,048 | 1,768 | 2,184 |
| Research and Development Expense [Member] | ||||
| Total stock-based compensation expense | $ 600 | $ 903 | $ 1,546 | $ 1,780 |