Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Stock Option Plan Activity (Details)

v3.10.0.1
Stockholders' Equity - Stock Option Plan Activity (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Shares [Rollforward]    
Balance at beginning of period (shares) 1,876,332  
Granted (shares) 228,362  
Exercised (shares) (358,162)  
Forfeited (shares) (10,228)  
Balance at end of period (shares) 1,736,304 1,876,332
Exercisable at end of period (shares) 1,313,374  
Options vested and expected to vest at end of period (shares) 1,734,304  
Weighted Average Exercise Price [Roll Forward]    
Balance at beginning of period (USD per share) $ 53.17  
Granted (USD per share) 162.00  
Exercised (USD per share) 55.24  
Forfeited (USD per share) 114.53  
Balance at end of period (USD per share) 66.71 $ 53.17
Exercisable at end of period (USD per share) 47.03  
Options vested and expected to vest at end of period (USD per share) $ 66.71  
Weighted Average Remaining Contractual Term in Years 5 years 5 months 19 days 5 years 9 months 7 days
Exercisable, Weighted Average Remaining Contractual Term in Years 4 years 6 months 21 days  
Options vested and expected to vest, Weighted Average Remaining Contractual Term in Years 5 years 5 months 19 days  
Aggregate Intrinsic Value $ 125,858 $ 157,340
Exercisable, Aggregate Intrinsic Value 117,314  
Options vested and expected to vest, Aggregate Intrinsic Value $ 125,858