Note 2 - Investments and Fair Value Measurement - Summary of Changes in Fair Value of Level III Financial Liabilities (Details) - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2022 |
Sep. 30, 2021 |
Sep. 30, 2022 |
Sep. 30, 2021 |
|
| Fair value, Beginning of period | $ 49 | $ 128 | $ 81 | $ 246 |
| Change in fair value of contingent put option associated with the Loan Agreement | (22) | (54) | ||
| Change in fair value of contingent put option associated with the Loan Agreement | (19) | (137) | ||
| Fair value, End of period | $ 27 | $ 109 | $ 27 | $ 109 |