Note 6 - Stockholders' Equity and Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Total stock-based compensation expense | $ 5,681 | $ 1,759 |
| Research and Development Expense [Member] | ||
| Total stock-based compensation expense | 2,762 | 949 |
| General and Administrative Expense [Member] | ||
| Total stock-based compensation expense | 2,919 | 810 |
| Time-based Options [Member] | ||
| Total stock-based compensation expense | 4,107 | 1,163 |
| Performance-based Options [Member] | ||
| Total stock-based compensation expense | 0 | 8 |
| Market-based Options [Member] | ||
| Total stock-based compensation expense | 1,469 | 507 |
| Employee Stock Purchase Plan Award [Member] | ||
| Total stock-based compensation expense | $ 105 | $ 81 |