Note 4 - Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
|
| Amounts included in contract liabilities at the beginning of the period: Performance obligations satisfied – Amended Agreements | $ 79 | $ 158 | ||
| New activities in the period from performance obligations satisfied: Performance obligations satisfied – Amended Agreements | 649 | 677 | ||
| Revenue | 941 | $ 818 | 1,206 | $ 1,161 |
| Amended License Agreement [Member] | ||||
| Revenue | 728 | 835 | ||
| Royalty Revenue [Member] | ||||
| Revenue | 158 | 269 | ||
| Product [Member] | ||||
| Revenue | $ 55 | $ 102 | ||