Quarterly report pursuant to Section 13 or 15(d)

Note 4 - Stock-based Compensation (Details Textual)

v3.20.1
Note 4 - Stock-based Compensation (Details Textual) - USD ($)
3 Months Ended
Jun. 01, 2016
Mar. 31, 2020
Mar. 31, 2019
Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)   0 0  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)   1,220,000   1,349,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)   0 0  
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total   $ 332    
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Month)   60 days    
Share-based Payment Arrangement, Expense   $ 450 $ 4,454  
Share-based Payment Arrangement, Nonemployee [Member]        
Share-based Payment Arrangement, Expense   $ 0 $ 0  
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)   371,000    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number (in shares)   352,500    
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)   849,000    
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