XML 66 R51.htm IDEA: XBRL DOCUMENT v3.24.1
Note 9 - Share-based Compensation - Valuation Assumptions for Employee Stock Options (Details) - Share-Based Payment Arrangement, Option [Member]
12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Minimum [Member]    
Risk-free interest rate 3.70% 1.80%
Volatility 110.00% 116.00%
Expected term (in years) (Year) 6 years 3 months 6 years 3 months
Maximum [Member]    
Risk-free interest rate 4.90% 3.80%
Volatility 120.00% 122.00%
Expected term (in years) (Year) 10 years 10 years