Note 5 - Stockholders' Equity - Stock-based Compensation Expense 2 (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Stock-based compensation expense | $ 188 | $ 164 | $ 348 | $ 303 |
| Location, Statement of Income, Balance [Axis]: us-gaap:GeneralAndAdministrativeExpense | ||||
| Stock-based compensation expense | 101 | 89 | 186 | 162 |
| Location, Statement of Income, Balance [Axis]: us-gaap:ResearchAndDevelopmentExpense | ||||
| Stock-based compensation expense | $ 87 | $ 75 | $ 162 | $ 141 |