Annual report pursuant to Section 13 and 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
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Outstanding at beginning of period (in shares) 549,970  
Outstanding at beginning of period, weighted average exercise price (in dollars per share) $ 8.81  
Granted (in shares) 459,500  
Granted, weighted average exercise price (in dollars per share) $ 1.94  
Exercised (in shares) (4,000) 0
Exercised, weighted average exercise price (in dollars per share) $ 1.06  
Canceled and forfeited (in shares) (83,590)  
Canceled and Forfeited, weighted average exercise price (in dollars per share) $ 4.70  
Expired (in shares) (2,090)  
Expired, weighted average exercise price (in dollars per share) $ 61.75  
Outstanding at end of period (in shares) 919,790 549,970
Outstanding at end of period, weighted average exercise price (in dollars per share) $ 5.67 $ 8.81
Outstanding, weighted average remaining contractual life (Year) 6 years 6 months  
Exercisable at end of period (in shares) 549,024  
Exercisable at end of period, weighted average exercise price (in dollars per share) $ 8.40  
Exercisable, weighted average remaining contractual life (Year) 4 years 7 months 6 days