Quarterly report pursuant to Section 13 or 15(d)

Note 10 - Stock-based Compensation (Details Textual)

v3.19.2
Note 10 - Stock-based Compensation (Details Textual) - USD ($)
$ in Millions
6 Months Ended
Jun. 03, 2019
Jun. 30, 2019
Jun. 30, 2018
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Subscription Rate   17.50%    
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares   9,700,000    
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 Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount   $ 2.1    
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition   1 year 248 days    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance   6,078,000   4,489,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period   80,000,000  
Employee Stock Option Vesting Schedule II [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance   335,000 850,000  
Employee Stock Option Vesting Schedule I [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance     116,000  
Restricted Stock Units (RSUs) [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period 80,000      
Share-based Payment Arrangement, Tranche One [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage   50.00% 50.00%  
Share-based Payment Arrangement, Tranche One [Member] | Employee Stock Option Vesting Schedule II [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage   100.00%    
Share-based Payment Arrangement, 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 Payment Arrangement, Tranche One [Member] | Restricted Stock Units (RSUs) [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period 90 days      
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period 40,000      
Share-based Payment Arrangement, Tranche Two [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage   16.67% 16.67%  
Share-based Payment Arrangement, 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%  
Share-based Payment Arrangement, Tranche Two [Member] | Restricted Stock Units (RSUs) [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period 1 year      
Share-based Compensation Award, Tranche Four [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage   16.67% 16.67%  
Share-based Payment Arrangement, Tranche Three [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage   16.67% 16.67%