Quarterly report pursuant to Section 13 or 15(d)

Note 12 - Summary of Stock Options (Details Textual)

v3.21.2
Note 12 - Summary of Stock Options (Details Textual) - USD ($)
$ / shares in Units, Pure in Thousands
1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Jan. 31, 2021
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Dec. 31, 2020
May 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)   3,188,628   3,188,628   986,399  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)   $ 7.54   $ 7.54   $ 19.10  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)       9 years 6 months   8 years 10 months 24 days  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)       2,220,600      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)       (0)      
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate   0.00%   0.00% 0.00%    
Restricted Stock Units (RSUs) [Member]              
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total   $ 1,724,000   $ 1,724,000      
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)       1 year 6 months      
Share-based Payment Arrangement, Option [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate       0.00%      
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total   $ 7,712,000   $ 7,712,000      
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)       3 years 1 month 6 days      
The 2006 Stock Option Plan [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)   12   12      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)   0   0      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)   $ 9,920.00   $ 9,920.00      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)       1 year 7 months 6 days      
The 2013 Plan [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)   3,188,616   3,188,616      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)   68,863   68,863      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)   $ 7.51   $ 7.51      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)       9 years 6 months      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares) 307,705            
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares) 1,758,951 3,940,136   3,940,136   1,451,246  
The 2013 Plan [Member] | Employees and Nonemployees [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)   2,213,600   2,200,600 46,800    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)   $ 1.87   $ 1.87 $ 5.23    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)     0        
The 2013 Plan [Member] | Restricted Stock Units (RSUs) [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance (in shares)   684,000   684,000      
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)     0   0    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period (in shares)   3,000   6,000      
The 2013 Plan [Member] | Restricted Stock Units (RSUs) [Member] | Employees and Board Members [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares) 690,000            
The 2013 Plan [Member] | Restricted Stock [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number, Ending Balance (in shares)   232   232      
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)   0 0 0 0    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period (in shares)   0 3 2 3    
2017 Employee Stock Purchase Plan [Member]              
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)   500,000   500,000      
Common Stock, Capital Shares Reserved for Future Issuance (in shares)   500,378   500,378     400
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant During Offering Period (in shares)   2,000   2,000     2