Note 11 - Stock-based Compensation - Share-based Payment Expense (Details) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2022 |
Mar. 31, 2021 |
|
| Share-based payment expense | $ 2,514 | $ 6,643 |
| Research and Development Expense [Member] | ||
| Share-based payment expense | 946 | 1,378 |
| General and Administrative Expense [Member] | ||
| Share-based payment expense | $ 1,568 | $ 5,265 |
| 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
|