Note 8 - Stockholders' Equity - Valuation Assumptions for Stock Options (Details) - Share-Based Payment Arrangement, Option [Member] - $ / shares Rate in Thousands |
3 Months Ended | |
---|---|---|
Dec. 31, 2022 |
Dec. 31, 2021 |
|
Dividend yield | 0.00% | |
Director [Member] | ||
Weighted-average fair value per share option (in dollars per share) | $ 1.12 | |
Expected life (in years) (Year) | 6 years | |
Volatility | 108.50% | |
Risk-free interest rate | 3.80% | |
Dividend yield | 0.00% | |
Non-Board of Directors [Member] | ||
Weighted-average fair value per share option (in dollars per share) | $ 2.96 | |
Expected life (in years) (Year) | 6 years | |
Volatility | 90.80% | |
Risk-free interest rate | 1.10% | |
Dividend yield | 0.00% |