Quarterly report pursuant to Section 13 or 15(d)

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

v3.8.0.1
Stockholders' Equity - Summary of Stock Options Activity (Details) - $ / shares
 3 Months Ended 12 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Class Of Stock [Line Items]    
Stock Options Outstanding, Beginning balance 1,836,426  
Stock Options, Exercised (169,594)  
Stock Options Outstanding, Ending balance 1,666,832 1,836,426
Stock Options, Vested and exercisable 1,134,940  
Stock Options, Vested and expected to vest 1,631,773  
Outstanding, Weighted-average exercise price, Beginning balance $ 30.77  
Weighted-average exercise price, Exercised 26.29  
Outstanding, Weighted-average exercise price, Ending balance 31.23 $ 30.77
Weighted-average exercise price, Vested and exercisable 25.82  
Weighted-average exercise price, Vested and expected to vest $ 30.98  
Remaining weighted-average contractual term, Outstanding 4 years 5 months 12 days 4 years 6 months 29 days
Remaining weighted-average contractual term, Vested and exercisable 4 years 3 months 21 days  
Remaining weighted-average contractual term, Vested and expected to vest 4 years 5 months 8 days  
Outstanding, Per share average intrinsic value $ 91.61 $ 88.31
Per share average intrinsic value, Vested and exercisable 97.02  
Per share average intrinsic value, Vested and expected to vest 91.86  
Minimum    
Class Of Stock [Line Items]    
Outstanding, Price per share, Beginning balance 0.60  
Price per share, Exercised 0.60  
Outstanding, Price per share, Ending balance 0.60 0.60
Price per share, Vested and exercisable 0.60  
Price per share, Vested and expected to vest 0.60  
Maximum    
Class Of Stock [Line Items]    
Outstanding, Price per share, Beginning balance 83.30  
Price per share, Exercised 58.95  
Outstanding, Price per share, Ending balance 83.30 $ 83.30
Price per share, Vested and exercisable 83.30  
Price per share, Vested and expected to vest $ 83.30