Quarterly report pursuant to Section 13 or 15(d)

Note 5 - Stock-based Compensation - Stock Option Activity (Details)

v3.21.1
Note 5 - Stock-based Compensation - Stock Option Activity (Details) - USD ($)
 3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Outstanding, shares (in shares) 1,395,000 1,349,000
Outstanding, weighted average exercise price (in dollars per share) $ 0.31 $ 0.23
Options granted, shares (in shares) 145,000 0
Options granted, weighted average exercise price (in dollars per share) $ 2.62
Options exercised, shares (in shares) (25,000) 0
Options exercised, weighted average exercise price (in dollars per share) $ 0.14
Options expired (in shares) (129,000)
Options expired, weighted average exercise price (in dollars per share) $ 0.17
Options forfeited, shares (in shares)
Options forfeited, weighted average exercise price (in dollars per share)
Outstanding, weighted average remaining contractual term (Month) 4 years 150 days 3 years 330 days
Outstanding, aggregate intrinsic value $ 3,585,623
Exercisable, shares (in shares) 1,135,000 1,201,500
Exercisable, weighted average exercise price (in dollars per share) $ 0.25 $ 0.24
Exercisable, weighted average remaining contractual term (Month) 3 years 30 days 3 years 300 days
Exercisable, aggregate intrinsic value $ 3,013,473
Outstanding, shares (in shares) 1,515,000 1,220,000
Outstanding, weighted average exercise price (in dollars per share) $ 0.53 $ 0.24