Share-Based Payments - Additional Information (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expense related to stock option	$ 37.5
Weighted-average period to recognize compensation expense (in years)	2 years
Market-Based Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expense related to stock option	$ 1.3
Weighted-average period to recognize compensation expense (in years)	1 year 2 months 12 days
2007 Plan and 2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance (in shares)	9,475,602
2013 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)	2,194,806
Total unrecognized compensation expense related to stock option	$ 114.6
Weighted-average period to recognize compensation expense (in years)	2 years 9 months 18 days
2013 Stock Incentive Plan \| Performance-Based Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expense related to stock option	$ 9.8
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)	128,126
Shares issued under 2013 ESPP (in shares)	32,410	27,377
Opportunity to purchase of common stock (in shares)	327,272

Aggregate number of common shares reserved for future issuance.

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