Note 6 - Equity - Stock based Compensation (Details) - USD ($) $ in Thousands |
12 Months Ended | |
---|---|---|
Dec. 31, 2022 |
Dec. 31, 2021 |
|
Stock-based compensation expense | $ 2,275 | $ 2,373 |
General and Administrative Expense [Member] | ||
Stock-based compensation expense | 1,467 | 1,461 |
Research and Development Expense [Member] | ||
Stock-based compensation expense | $ 808 | $ 912 |