Quarterly report pursuant to Section 13 or 15(d)

Note 6 - Stock-based Compensation - Stock Option Activity (Details)

v3.21.2
Note 6 - Stock-based Compensation - Stock Option Activity (Details) - USD ($)
3 Months Ended 9 Months Ended
Sep. 30, 2021
Jun. 30, 2021
Mar. 31, 2021
Sep. 30, 2020
Jun. 30, 2020
Mar. 31, 2020
Sep. 30, 2021
Sep. 30, 2020
Outstanding, shares (in shares) 1,262,500 1,515,000 1,395,000 1,220,000 1,220,000 1,349,000 1,395,000 1,349,000
Outstanding, weighted average exercise price (in dollars per share) $ 0.86 $ 0.53 $ 0.31 $ 0.24 $ 0.24 $ 0.23 $ 0.31 $ 0.23
Options granted, shares (in shares) 30,000 127,500 145,000 210,000 10,000 0 302,500 220,000
Options granted, weighted average exercise price (in dollars per share) $ 2.80 $ 2.85 $ 2.62 $ 0.66 $ 0.15      
Options exercised, shares (in shares) (65,000) (360,000) (25,000) 0     (450,000) 0
Options exercised, weighted average exercise price (in dollars per share) $ 0.18 $ 0.22 $ 0.14          
Options expired, shares (in shares)   (20,000)     (10,000) (129,000)    
Options expired (in dollars per share)   $ 0.17     $ 0.19 $ 0.17    
Outstanding, shares (in shares) 1,227,500 1,262,500 1,515,000 1,430,000 1,220,000 1,220,000 1,227,500 1,430,000
Outstanding, weighted average exercise price (in dollars per share) $ 0.94 $ 0.86 $ 0.53 $ 0.30 $ 0.24 $ 0.24 $ 0.94 $ 0.30
Outstanding, weighted average remaining contractual term (Month) 61 months     53 months        
Outstanding, aggregate intrinsic value $ 2,450,068     $ 487,773     $ 2,450,068 $ 487,773
Exercisable, shares (in shares) 930,000     1,208,500     930,000 1,208,500
Exercisable, weighted average exercise price (in dollars per share) $ 0.44     $ 0.24     $ 0.44 $ 0.24
Exercisable, weighted average remaining contractual term (Month) 53 months     41 months        
Exercisable, aggregate intrinsic value $ 2,326,943     $ 482,268     $ 2,326,943 $ 482,268