XML 114 R90.htm IDEA: XBRL DOCUMENT v3.10.0.1
Stock-Based Compensation - Restricted Stock Unit Activity (Details) - Restricted stock units - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Number of RSUs      
Beginning balance (in shares) 558,268    
Granted (in shares) 381,545 534,146 61,482
Vested (in shares) (36,051)    
Forfeited (in shares) (32,010)    
Ending balance (in shares) 871,752 558,268  
Weighted Average Grant Date Fair Value      
Beginning balance (USD per share) $ 34.71    
Granted (USD per share) 43.03    
Vested (USD per share) 32.29    
Forfeited (USD per share) 37.04    
Ending balance (USD per share) $ 38.37 $ 34.71  
Aggregate Intrinsic Value (in thousands)      
Beginning balance $ 21,075    
Vested 1,734    
Ending balance $ 45,218 $ 21,075  
Vested and expected to vest (in shares) 871,752    
Vested and expected to vest (USD per share) $ 38.37    
Vested and expected to vest, aggregate intrinsic value $ 45,218