Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation - Additional Information (Details)

v3.19.3
Stock Based Compensation - Additional Information (Details) - USD ($)
1 Months Ended 9 Months Ended 12 Months Ended
Aug. 31, 2019
Sep. 30, 2019
Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Weighted average grant-date fair value of options granted   $ 4.18 $ 3.97
Stock options vested aggregate intrinsic value   $ 3,043,000 $ 2,485,000
Stock options expected to vest aggregate intrinsic value   $ 935,000 993,000
Employee Stock Purchase Plan      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Offering period of employee stock purchase plan   6 months  
Terms of stock purchase plane   The ESPP is implemented through consecutive 6-month offering periods commencing on March 1 and September 1 of each year.  
Limited percentage of annual contribution   20.00%  
Percentage of discount and fair value of option   15.00%  
Proceeds from stock issued during period $ 97,000    
Number of stock issued during period 10,000    
Employee Stock Purchase Plan | Maximum      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Purchase price percentage of market value of common stock   85.00%  
Restricted Stock      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Total unrecognized compensation cost   $ 4,090,000 $ 2,781,000
Unrecognized compensation cost related to unvested stock options and restricted stock granted under the Company's equity plans, period for recognition   3 years  
Restricted Stock Units [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Total unrecognized compensation cost   $ 919,000  
Restricted stock outstanding   96,605,000  
Weighted average grant date fair value   $ 11.42  
Restricted stock granted   95,478,000  
Weighted average price, grant date value   $ 11.35  
Restricted stock vested   0  
Weighted average remaining contractual term   1 year 9 months 18 days