Note 14 - Stock Based Compensation - Assumptions to Calculate Fair Value of Each Performance-based Stock Option (Details) - Performance Shares [Member]
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Risk-free interest rate 1.50% 0.00%
Expected volatility 90.00% 0.00%
Expected dividend rate 0.00% 0.00%
Minimum [Member]    
Derived service period (in years) (Year) 2 years 3 months 18 days  
Maximum [Member]    
Derived service period (in years) (Year) 2 years 7 months 6 days