Annual report pursuant to Section 13 and 15(d)

Note 12 - Stock-based Compensation (Details Textual)

v3.22.1
Note 12 - Stock-based Compensation (Details Textual) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Jul. 10, 2020
Jul. 02, 2020
May 05, 2020
Mar. 10, 2020
Jun. 03, 2019
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Nov. 11, 2021
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares (in shares)           6,343,242        
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)           10 years        
Employee Stock Purchase Plan, Maximum Payroll Deduction, Percent           15.00%        
Employee Stock Purchase Plan, Stock Purchase Price, Percent           85.00%        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)           15,112,000 11,942,000     5,941,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value           $ 222 $ 850      
Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount           $ 6,000        
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)           1 year 8 months 4 days        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number (in shares)           8,164,000        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price (in dollars per share)           $ 4.50        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term (Month)           5 years 3 months 18 days        
Share-based Payment Arrangement, Expense           $ 12,949 $ 21,438      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)           4,659,000 6,362,000 6,362,000    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number (in shares)           14,068,000        
Restricted Stock Units (RSUs) [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)   40,000   645,000 80,000 0 645,000      
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Month)     4 months 3 months            
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures, Total (in shares) 645,000                  
Restricted Stock Units (RSUs) [Member] | Share-based Payment Arrangement, Tranche One [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)         40,000          
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Month)         3 months          
Restricted Stock Units (RSUs) [Member] | Share-based Payment Arrangement, Tranche Two [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Month)     13 months   1 year          
Officer [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number (in shares)           1,679,169        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term (Month)           12 months        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term (Month)           12 months        
Officer [Member] | Continuing Vesting Options with No Service Requirement [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award, Accelerated Vesting, Number (in shares)           504,833        
Officer [Member] | Vested Options [Member]                    
Share-based Payment Arrangement, Expense           $ 945        
Officer [Member] | Unvested Options [Member]                    
Share-based Payment Arrangement, Expense           $ 663        
Officer [Member] | Performance Shares [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)           800,000        
Officer [Member] | Minimum [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price (in dollars per share)           $ 1.03        
Officer [Member] | Maximum [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price (in dollars per share)           $ 7.44        
Officer One [Member] | Performance Shares [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)           400,000        
Officer One [Member] | Performance Shares [Member] | Share-based Payment Arrangement, Tranche One [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number (in shares)           200,000     200,000  
Officer One [Member] | Performance Shares [Member] | Share-based Payment Arrangement, Tranche Two [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number (in shares)           200,000        
Officer Two [Member] | Performance Shares [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)           400,000        
Officer Two [Member] | Performance Shares [Member] | Share-based Payment Arrangement, Tranche One [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number (in shares)           200,000        
Officer Two [Member] | Performance Shares [Member] | Share-based Payment Arrangement, Tranche Two [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number (in shares)           200,000        
ESPP [Member]                    
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)           1,700,000        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)           0