Annual report pursuant to Section 13 and 15(d)

Note 9 - Stock-based Compensation (Details Textual)

v3.19.1
Note 9 - Stock-based Compensation (Details Textual) - USD ($)
3 Months Ended 12 Months Ended
Jul. 13, 2018
Mar. 28, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Subscription Rate     17.50%   17.50%    
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares     6,700,000   6,700,000    
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period         4 years    
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period         10 years    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value         $ 255,000 $ 0  
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options     $ 1,280,000   $ 1,280,000    
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition         1 year 302 days    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance     4,489,000 2,344,000 4,489,000 2,344,000 2,005,000
Allocated Share-based Compensation Expense, Total         $ 4,276 $ 817  
Employee Stock Option Vesting Schedule II [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance     166,000 185,000 166,000 185,000  
Employee Stock Option Vesting Schedule III [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance     850,000   850,000    
Employee Stock Option Vesting Schedule I [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance       641,500   641,500  
Restricted Stock Units (RSUs) [Member]              
Stock Redemption, Shares Per Share     1   1    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period 150,000 150,000     150,000 150,000  
Allocated Share-based Compensation Expense, Total     $ 66,000 $ 0 $ 503,000 $ 171,000  
Share-based Compensation Award, Tranche One [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage         50.00%    
Share-based Compensation Award, Tranche One [Member] | Employee Stock Option Vesting Schedule II [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage         50.00% 50.00%  
Share-based Compensation Award, Tranche One [Member] | Employee Stock Option Vesting Schedule I [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage           50.00%  
Share-based Compensation Award, Tranche Four [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage         16.67%    
Share-based Compensation Award, Tranche Four [Member] | Employee Stock Option Vesting Schedule I [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage           16.67%  
Share-based Compensation Award, Tranche Two [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage         16.67%    
Share-based Compensation Award, Tranche Two [Member] | Employee Stock Option Vesting Schedule II [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage         25.00% 25.00%  
Share-based Compensation Award, Tranche Two [Member] | Employee Stock Option Vesting Schedule I [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage           16.67%  
Share-based Compensation Award, Tranche Three [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage         16.67%    
Share-based Compensation Award, Tranche Three [Member] | Employee Stock Option Vesting Schedule II [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage         25.00% 25.00%  
Share-based Compensation Award, Tranche Three [Member] | Employee Stock Option Vesting Schedule I [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage           16.67%