Quarterly report pursuant to Section 13 or 15(d)

Note 4 - Stock-based Compensation - Summary of Stock Option Activity (Details)

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Note 4 - Stock-based Compensation - Summary of Stock Option Activity (Details) - $ / shares
 6 Months Ended 12 Months Ended
Jun. 30, 2022
Dec. 31, 2021
Outstanding at beginning of period (in shares) 919,790  
Outstanding at beginning of period, weighted average exercise price (in dollars per share) $ 5.67  
Outstanding, weighted average remaining contractual life (Year) 6 years 6 years 6 months
Granted (in shares) 12,500  
Granted, weighted average exercise price (in dollars per share) $ 0.83  
Cancelled/Forfeited (in shares) (152,455)  
Cancelled/Forfeited, weighted average exercise price (in dollars per share) $ 2.38  
Expired (in shares) (53,755)  
Expired, weighted average exercise price (in dollars per share) $ 29.32  
Outstanding at end of period (in shares) 726,080 919,790
Outstanding at end of period, weighted average exercise price (in dollars per share) $ 4.52 $ 5.67
Exercisable at end of period (in shares) 545,665  
Exercisable at end of period, weighted average exercise price (in dollars per share) $ 5.52  
Exercisable, weighted average remaining contractual life (Year) 4 years 10 months 24 days