v3.22.2.2
Note 7 - Stock Option Plan and Stock-based Compensation - Stock Option Activity (Details) - $ / shares
6 Months Ended 12 Months Ended
Jun. 30, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Options outstanding (in shares) 192,898 192,898 65,471 112,932
Beginning balance, weighted average exercise price per share (in dollars per share) $ 8.46 $ 8.46 $ 16.86 $ 15.37
Weighted average remaining contractual life (Year) 6 years 3 months 7 days 6 years 9 months 3 days    
Vested and expected to vest (in shares) 192,898 192,898    
Vested and expected to vest, weighted average exercise price per share (in dollars per share) $ 8.46 $ 8.46    
Vested and expected to vest, weighted average remaining contractual term (Year) 6 years 3 months 7 days      
Shares exercisable (in shares) 112,744 95,803    
Weighted average exercise price (in dollars per share) $ 11.51 $ 8.46    
Options exercisable, weighted average remaining contractual term (Year) 4 years 3 months 18 days      
Share-Based Payment Arrangement, Option [Member]        
Beginning balance, number of shares available for grant (in shares) 1,257,334 1,257,334 461,587 343,871