Annual report pursuant to Section 13 and 15(d)

Note 11 - Stock Options and Warrants (Details Textual)

v3.21.1
Note 11 - Stock Options and Warrants (Details Textual) - USD ($)
12 Months Ended
Jun. 01, 2016
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
May 18, 2006
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)   1,395,000 1,349,000 1,376,500  
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total   $ 58,553      
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Month)   150 days      
The 2016 Stock Incentive Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares) 1,000,000        
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year) 10 years        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)   606,000 371,000    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number (in shares)   371,000 347,500    
The 2006 Stock Incentive Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)         1,950,000
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)   10 years      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number (in shares)   789,000 978,000    
Minimum [Member] | Share-based Payment Arrangement, Option [Member]          
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Month)   180 days      
Maximum [Member] | Share-based Payment Arrangement, Option [Member]          
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Month)   2 years