Quarterly report pursuant to Section 13 or 15(d)

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

v3.20.1
Note 4 - Stock-based Compensation - Stock Option Activity (Details) - USD ($)
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Outstanding, shares (in shares) 1,349,000  
Outstanding, weighted average exercise price (in dollars per share) $ 0.23  
Options granted, shares (in shares) 0 0
Options granted, weighted average exercise price (in dollars per share)  
Options exercised, shares (in shares) 0 0
Options exercised, weighted average exercise price (in dollars per share)  
Options expired, shares (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, shares (in shares) 1,220,000  
Outstanding, weighted average exercise price (in dollars per share) $ 0.24  
Outstanding, weighted average remaining contractual term (Year) 3 years 335 days  
Outstanding, aggregate intrinsic value  
Exercisable, shares (in shares) 1,201,500  
Exercisable, weighted average exercise price (in dollars per share) $ 0.24  
Exercisable, weighted average remaining contractual term (Year) 3 years 302 days  
Exercisable, aggregate intrinsic value