Equity-based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award Options Additional Disclosures [Abstract]
Shares, Outstanding, Beginning Balance	6,689,311
Shares, Granted	2,832,784	2,209,597	2,999,847
Shares, Exercised	(1,180,644)
Shares, Cancelled or forfeited	(559,014)
Shares, Outstanding, Ending Balance	7,782,437	6,689,311
Shares, Exercisable	3,328,398
Shares, Vested or expected to vest	7,782,437
Weighted-Average Exercise Price, Outstanding, Beginning Balance	$ 25.42
Weighted-Average Exercise Price, Granted	39.16	$ 51.73	$ 16.98
Weighted-Average Exercise Price, Exercised	14.91
Weighted-Average Exercise Price, Cancelled or forfeited	35.35
Weighted-Average Exercise Price, Outstanding, Ending Balance	31.30	$ 25.42
Weighted-Average Exercise Price, Exercisable	24.07
Weighted-Average Exercise Price, Vested or expected to vest	$ 31.30
Weighted-Average Remaining Contractual Term	8 years 2 months 12 days	8 years 3 months 18 days
Weighted-Average Remaining Contractual Term, Exercisable	7 years 4 months 24 days
Weighted-Average Remaining Contractual Term, Vested or expected to vest	8 years 2 months 12 days
Aggregate Intrinsic Value, Outstanding Balance	$ 231,554	$ 68,572
Aggregate Intrinsic Value, Exercisable	122,774
Aggregate Intrinsic Value, Vested or expected to vest	$ 231,554