Quarterly report pursuant to Section 13 or 15(d)

Note 12 - Summary of Stock Options (Details Textual)

v3.21.1
Note 12 - Summary of Stock Options (Details Textual) - USD ($)
1 Months Ended 3 Months Ended 12 Months Ended
Jan. 31, 2021
Mar. 31, 2021
Mar. 31, 2020
Dec. 31, 2020
Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)   981,551   986,399  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)   $ 18.42   $ 19.10  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)   8 years 292 days   8 years 328 days  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)   7,000      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)        
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate   0.00% 0.00%    
Restricted Stock Units (RSUs) [Member]          
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total   $ 2,011,000      
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)   1 year 292 days      
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   $ 4,186,000      
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)   2 years 109 days      
The 2006 Stock Option Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)   12      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)   0      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)   $ 9,920      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)   1 year 292 days      
The 2013 Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares)   981,539      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)   91,755      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price, Ending Balance (in dollars per share)   $ 18.29      
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)   8 years 292 days      
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     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)   7,000 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)   $ 2.19 $ 8.80    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)   0     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)   687,000      
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)     0    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period (in shares)   3,000      
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      
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)   0 0    
2017 Employee Stock Purchase Plan [Member]          
Employee Stock Ownership Plan (ESOP), Number of Suspense Shares (in shares)   22