| Note 12 - Share-based Compensation - Share-based Compensation Expense (Details) - USD ($) $ in Thousands | 3 Months Ended | |
|---|---|---|
| Mar. 31, 2025 | Mar. 31, 2024 | |
| Total share-based compensation | $ 867 | $ 488 | 
| General and Administrative Expense [Member] | ||
| Total share-based compensation | 678 | 293 | 
| Research and Development Expense [Member] | ||
| Total share-based compensation | $ 189 | $ 195 | 
| X | ||||||||||
| 
- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 |