v3.19.1
Share-Based Compensation - Option Activity (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]    
Options, Outstanding at beginning of period (in shares) 859,635  
Options, Granted (in shares) 110,000  
Options, Exercised (in shares) (51,621)  
Options, Forfeited (in shares) (19,723)  
Options, Outstanding at end of year (in shares) 898,291 859,635
Options, Exercisable (in shares) 551,017  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]    
Weighted-Average Exercise Price Per Share, Outstanding at beginning of period (in dollars per share) $ 8.84  
Weighted-Average Exercise Price Per Share, Granted (in dollars per share) 15.36  
Weighted-Average Exercise Price Per Share, Exercised (in dollars per share) 5.99  
Weighted-Average Exercise Price Per Share, Forfeited (in dollars per share) 10.14  
Weighted-Average Exercise Price Per Share, Outstanding at ending of period (in dollars per share) 9.81 $ 8.84
Weighted-Average Exercise Price Per Share, Exercisable (in dollars per share) $ 8.33  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]    
Weighted-Average Contractual Term, Outstanding 6 years 6 months 17 days 7 years 1 month 6 days
Weighted-Average Contractual Term, Granted 10 years  
Weighted-Average Contractual Term, Exercised 5 years 3 months 15 days  
Weighted-Average Contractual Term, Forfeited 6 years 11 months 6 days  
Weighted-Average Contractual Term, Exercisable 5 years 9 months 24 days  
Aggregate Intrinsic Value, Balance $ 5,243 $ 6,155
Aggregate Intrinsic Value, Exercisable $ 4,034