Quarterly report pursuant to Section 13 or 15(d)

Note 4 - Warrants - Warrant Activity (Details)

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Note 4 - Warrants - Warrant Activity (Details) - Liability Classified Warrants [Member] - $ / shares
6 Months Ended 12 Months Ended
Jun. 30, 2021
Dec. 31, 2021
Balance, number of shares under warrants (in shares) 2,733,645 2,733,645
Balance, weighted average remaining contractual life (Year) 3 years 1 month 6 days 3 years 7 months 6 days
Granted, number of shares under warrants (in shares) 0  
Exercised, number of shares under warrants (in shares) (10,000)  
Expired, number of shares under warrants (in shares) 0  
Balance, number of shares under warrants (in shares) 2,723,645  
Vested and Exercisable, number of shares under warrants (in shares) 2,723,645  
Vested and Exercisable, weighted average remaining contractual life (Year) 3 years 1 month 6 days  
Minimum [Member]    
Balance, warrant exercise price (in dollars per share) $ 6.30 $ 6.30
Granted, warrant exercise price (in dollars per share) 0  
Exercised, warrant exercise price (in dollars per share) 6.30  
Balance, warrant exercise price (in dollars per share) 6.30  
Vested and Exercisable, warrant exercise price (in dollars per share) 6.30  
Maximum [Member]    
Balance, warrant exercise price (in dollars per share) 16.80 16.80
Granted, warrant exercise price (in dollars per share) 0  
Exercised, warrant exercise price (in dollars per share) 6.30  
Balance, warrant exercise price (in dollars per share) 16.80  
Vested and Exercisable, warrant exercise price (in dollars per share) 16.80  
Weighted Average [Member]    
Balance, warrant exercise price (in dollars per share) 9.45 $ 9.45
Granted, warrant exercise price (in dollars per share) 0  
Exercised, warrant exercise price (in dollars per share) 6.30  
Balance, warrant exercise price (in dollars per share) 9.46  
Vested and Exercisable, warrant exercise price (in dollars per share) $ 9.46