Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Summary of Stock Options Activity (Details)

v3.8.0.1
Stockholders' Equity - Summary of Stock Options Activity (Details) - $ / shares
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Class Of Stock [Line Items]        
Stock Options Outstanding, Beginning balance 2,355,527 2,295,370 2,261,633  
Stock Options, Granted 64,498 683,998 759,301  
Stock Options, Exercised (520,393) (570,079) (676,715)  
Stock Options, Forfeited (63,173) (53,247) (48,849)  
Stock Options, Expired (33) (515)    
Stock Options Outstanding, Ending balance 1,836,426 2,355,527 2,295,370 2,261,633
Stock Options, Vested and exercisable 1,176,504 1,023,865 933,707  
Stock Options, Vested and expected to vest 1,792,871 2,259,811 2,179,294  
Price per share, Granted $ 83.30      
Price per share, Expired 8.70 $ 8.70    
Outstanding, Weighted-average exercise price, Beginning balance 28.22 19.36 $ 7.31  
Weighted-average exercise price, Granted 83.30 44.70 39.91  
Weighted-average exercise price, Exercised 24.16 12.32 2.39  
Weighted-average exercise price, Forfeited 43.74 28.09 16.28  
Weighted-average exercise price, Expired 8.70 8.70    
Outstanding, Weighted-average exercise price, Ending balance 30.77 28.22 19.36 $ 7.31
Weighted-average exercise price, Vested and exercisable 24.33 16.61 7.16  
Weighted-average exercise price, Vested and expected to vest $ 30.50 $ 27.95 $ 19.15  
Remaining weighted-average contractual term, Outstanding 4 years 6 months 29 days 5 years 5 months 1 day 5 years 11 months 23 days 6 years 5 months 4 days
Remaining weighted-average contractual term, Vested and exercisable 4 years 4 months 20 days 4 years 11 months 15 days 5 years 6 months 18 days  
Remaining weighted-average contractual term, Vested and expected to vest 4 years 6 months 29 days 5 years 4 months 24 days 5 years 11 months 15 days  
Outstanding, Per share average intrinsic value $ 88.31 $ 38.95 $ 21.07 $ 24.06
Per share average intrinsic value, Vested and exercisable 94.75 50.56 32.97  
Per share average intrinsic value, Vested and expected to vest 88.58 39.22 21.27  
Minimum        
Class Of Stock [Line Items]        
Outstanding, Price per share, Beginning balance 0.60 0.60 0.60  
Price per share, Granted   44.19 37.10  
Price per share, Exercised 0.60 0.60 0.60  
Price per share, Forfeited 24.52 1.17 0.75  
Outstanding, Price per share, Ending balance 0.60 0.60 0.60 0.60
Price per share, Vested and exercisable 0.60 0.60 0.60  
Price per share, Vested and expected to vest 0.60 0.60 0.60  
Maximum        
Class Of Stock [Line Items]        
Outstanding, Price per share, Beginning balance 58.95 46.66 24.52  
Price per share, Granted   58.95 46.66  
Price per share, Exercised 58.95 46.66 24.52  
Price per share, Forfeited 58.95 44.19 38.54  
Outstanding, Price per share, Ending balance 83.30 58.95 46.66 $ 24.52
Price per share, Vested and exercisable 83.30 46.66 46.66  
Price per share, Vested and expected to vest $ 83.30 $ 46.66 $ 46.66