Annual report pursuant to Section 13 and 15(d)

Equity Incentive Plan - Additional Information (Details)

v3.21.1
Equity Incentive Plan - Additional Information (Details) - USD ($)
1 Months Ended 12 Months Ended
Jan. 31, 2019
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized   $ 780,000 $ 627,000  
Fair value of options granted   $ 580,000 $ 355,000  
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition   1 year 11 months 12 days 1 year 7 months 13 days  
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding And Exercisable Intrinsic Value   $ 0 $ 32,000  
Excess Stock, Shares Authorized       59,414
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value   $ 6.26 $ 7.11  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period   0 79  
Number of Options, Granted   93,165 49,994  
Holders Owing More Than Ten Percentage Voting Rights [Member] | Minimum [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Percentage of Exercise Price   110.00%    
Equity Incentive Plan 2014 [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period   49,000    
ESPP [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant   7,806    
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized   11,371    
2014 Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant   176,524    
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized 582,672 582,672    
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized 23,333      
Restricted Stock        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]        
Fair value of options granted     $ 321,000  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period     7,659  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period   49,000