Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.2
Note 4 - Stock-based Compensation - Stock Option Activity (Details) - USD ($)
 3 Months Ended 6 Months Ended
Jun. 30, 2019
Mar. 31, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Outstanding, shares, Beginning Balance (in shares) 1,372,000 1,376,500   1,376,500  
Outstanding, weighted average exercise price (in dollars per share) $ 0.23 $ 0.23   $ 0.23  
Options granted, shares (in shares) 3,000      
Options granted, weighted average exercise price (in dollars per share) $ 0.21      
Options exercised, shares (in shares) (10,000) 0 (10,000) 0
Options exercised, weighted average exercise price (in dollars per share) $ 0.10      
Options expired, shares (in shares) (11,000) (4,500)      
Options expired, weighted average exercise price (in dollars per share) $ 0.08 $ 0.13      
Options forfeited, shares (in shares) (2,500)      
Options forfeited, weighted average exercise price (in dollars per share) $ 0.46      
Outstanding, shares (in shares) 1,351,500 1,372,000   1,351,500  
Outstanding, weighted average exercise price (in dollars per share) $ 0.23 $ 0.23   $ 0.23  
Outstanding, weighted average remaining contractual term (Year) 4 years 120 days        
Outstanding, aggregate intrinsic value $ 33,783     $ 33,783  
Exercisable, shares (in shares) 1,322,500     1,322,500  
Exercisable, weighted average exercise price (in dollars per share) $ 0.23     $ 0.23  
Exercisable, weighted average remaining contractual term (Year) 4 years 91 days        
Exercisable, aggregate intrinsic value $ 33,783     $ 33,783