Equity Awards - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of Shares
Number of shares, outstanding, beginning balance (in shares)	1,811,000	3,370,000
Number of shares granted (in shares)	161,000	0
Number of shares, exercised (in shares)	(640,000)	(1,462,000)
Number of shares, canceled (in shares)	(178,000)	(97,000)
Number of shares, outstanding, ending balance (in shares)	1,154,000	1,811,000	3,370,000
Number of shares, vested and expected to vest (in shares)	1,119,000
Number of shares, vested and exercisable (in shares)	907,000
Weighted- Average Exercise Price Per Share
Weighted-average exercise price, outstanding, beginning balance (in USD per share)	$ 46.55	$ 38.43
Weighted-average exercise price, granted (in USD per share)	266.31
Weighted-average exercise price, exercised (in USD per share)	34.61	26.23
Weighted-average exercise price, canceled (in USD per share)	86.02	70.52
Weighted-average exercise price, outstanding, ending balance (in USD per share)	77.70	$ 46.55	$ 38.43
Weighted-average exercise price, vested and expected to vest (in USD per share)	72.37
Weighted-average exercise price, vested and exercisable (in USD per share)	$ 43.75
Weighted-average remaining contractual life (in years)	5 years 1 month 6 days
Weighted-average remaining contractual term, vested and expected to vest (in years)	5 years
Weighted-average remaining contractual term, vested and exercisable (in years)	4 years 1 month 6 days
Total intrinsic value of options exercised	$ 138,389	$ 204,337	$ 277,700
Aggregate intrinsic value, outstanding	236,055
Aggregate intrinsic value, vested and expected to vest	234,889
Aggregate intrinsic value, vested and exercisable	$ 216,458