Quarterly report pursuant to Section 13 or 15(d)

Stock-based Compensation - Stock Option Activity (Details)

v3.21.2
Stock-based Compensation - Stock Option Activity (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2020
Dec. 31, 2020
Share-based compensation        
Number of shares, Outstanding at beginning of period   1,827,906    
Number of shares, Granted 0 213,711    
Number of shares, Exercised   (74,805)    
Number of shares, Forfeited, expired or cancelled   (57,115)    
Number of shares, Outstanding at end of period   1,909,697   1,827,906
Number of shares, Exercisable at end of period   1,595,665    
Weighted Average Exercise Price Per Share, Outstanding at beginning of period   $ 20.66    
Weighted Average Exercise Price Per Share, Granted   36.32    
Weighted Average Exercise Price Per Share, Exercised   13.54    
Weighted Average Exercise Price Per Share, Forfeited, expired or cancelled   71.26    
Weighted Average Exercise Price Per Share, Outstanding at end of period   21.18   $ 20.66
Weighted Average Exercise Price Per Share, Exercisable at end of period   $ 19.53    
Weighted Average Contractual Term, Outstanding   6 years 7 days   6 years 3 months 21 days
Weighted Average Contractual Term, Exercisable   5 years 5 months 12 days    
Aggregate Intrinsic Value, Outstanding   $ 20,077   $ 51,401
Aggregate Intrinsic Value, Exercisable   19,276    
Options exercised, aggregate intrinsic value   $ 1,600 $ 100  
Stock Options [Member]        
Share-based compensation        
Weighted-average grant-date fair value (in dollars per share)   $ 26.21 $ 16.22  
Unrecognized compensation expense related to stock options (in dollars)   $ 4,200    
Weighted average period of unrecognized compensation expense expected to be recognized   1 year 10 months 20 days