Quarterly report pursuant to Section 13 or 15(d)

Note 11 - Stock-based Compensation (Details Textual)

v3.22.1
Note 11 - Stock-based Compensation (Details Textual) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2022
Mar. 31, 2021
Dec. 31, 2021
Jun. 01, 2021
Common Stock, No Par Value (in dollars per share) $ 0   $ 0  
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%      
Stock Issued During Period, Shares, Employee Stock Purchase Plans (in shares) 0   0  
Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount $ 6,990      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number (in shares) 10,736,000 7,887,000    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price (in dollars per share) $ 4.68 $ 4.59    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term (Month) 5 years 6 months 5 years 11 months 12 days    
Share-based Payment Arrangement, Expense $ 2,514 $ 6,643    
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    
Share-Based Payment Arrangement, Option [Member]        
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year) 1 year 8 months 1 day      
Continuing Vesting Options with No Service Requirement [Member] | Officer [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Accelerated Vesting, Number (in shares)   504,833    
Vested Options [Member] | Officer [Member]        
Share-based Payment Arrangement, Expense   $ 945    
Unvested Options [Member] | Officer [Member]        
Share-based Payment Arrangement, Expense   $ 663    
Maximum [Member] | Officer [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price (in dollars per share)   $ 7.44    
Minimum [Member] | Officer [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price (in dollars per share)   $ 1.03    
New Incentive Plan [Member]        
Common Stock, No Par Value (in dollars per share)       $ 0
New Incentive Plan [Member] | Maximum [Member]        
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares)       6,343,242
ESPP [Member]        
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) 1,700,000      
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year) 4 months      
Share-Based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount $ 6