Annual report pursuant to Section 13 and 15(d)

Note 4 - Stock-based Compensation - Summary of Stock Option Activity (Details)

v3.21.1
Note 4 - Stock-based Compensation - Summary of Stock Option Activity (Details)
 12 Months Ended
Dec. 31, 2020
USD ($)
$ / shares
shares
Outstanding at beginning of period (in shares) | shares 238,470
Outstanding at beginning of period, weighted average exercise price (in dollars per share) | $ / shares $ 17.38
Granted (in shares) | shares 315,000
Granted, weighted average exercise price (in dollars per share) | $ / shares $ 2.29
Canceled and forfeited (in shares) | shares (3,000)
Canceled and Forfeited, weighted average exercise price (in dollars per share) | $ / shares $ 1.06
Expired (in shares) | shares (500)
Expired, weighted average exercise price (in dollars per share) | $ / shares $ 30.80
Outstanding at end of period (in shares) | shares 549,970
Outstanding at end of period, weighted average exercise price (in dollars per share) | $ / shares $ 8.81
Outstanding, weighted average remaining contractual life (Year) 8 years
Outstanding, aggregate intrinsic value | $ $ 209,280
Exercisable at end of period (in shares) | shares 119,870
Exercisable at end of period, weighted average exercise price (in dollars per share) | $ / shares $ 24.54
Exercisable, weighted average remaining contractual life (Year) 5 years 36 days
Exercisable, aggregate intrinsic value | $