Note 12 - Share-based Compensation - Share-based Compensation Expense (Details) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2022 |
Mar. 31, 2021 |
|
| Total share-based compensation | $ 308 | $ 511 |
| Research and Development Expense [Member] | ||
| Total share-based compensation | 91 | 131 |
| General and Administrative Expense [Member] | ||
| Total share-based compensation | $ 217 | $ 380 |
| 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
|