Quarterly report pursuant to Section 13 or 15(d)

Note 4 - Warrants - Warrant Activity (Details)

v3.21.2
Note 4 - Warrants - Warrant Activity (Details) - Liability Classified Warrants [Member] - $ / shares
9 Months Ended 12 Months Ended
Sep. 30, 2021
Dec. 31, 2020
Balance, number of shares under warrants (in shares) 2,733,645  
Balance, weighted average remaining contractual life (Year) 2 years 10 months 24 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 2,733,645
Vested and Exercisable, number of shares under warrants (in shares) 2,723,645  
Vested and Exercisable, weighted average remaining contractual life (Year) 2 years 10 months 24 days  
Minimum [Member]    
Balance, warrant exercise price (in dollars per share) $ 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 $ 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  
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 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  
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 $ 9.45
Vested and Exercisable, warrant exercise price (in dollars per share) $ 9.46