Note 10 - Stock-based Compensation - Share-based Payment Expense (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2019 |
Sep. 30, 2018 |
Sep. 30, 2019 |
Sep. 30, 2018 |
|
| Share-based payment expense | $ 504 | $ 951 | $ 1,734 | $ 3,695 |
| Research and Development Expense [Member] | ||||
| Share-based payment expense | 34 | 307 | 309 | 826 |
| General and Administrative Expense [Member] | ||||
| Share-based payment expense | $ 470 | $ 644 | $ 1,425 | $ 2,869 |
| X | ||||||||||
- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
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