Equity Award Plan Activities - Option and RSA Activity Rollforward (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Number of Shares Underlying Outstanding Options
Outstanding, beginning balance (in shares)	11,630
Options granted (in shares)	441
Options exercised (in shares)	(2,200)
Options canceled (in shares)	(362)
Outstanding, ending balance (in shares)	9,509	11,630
Vested and exercisable (in shares)	3,642
Vested and expected to vest (in shares)	9,050
Weighted- Average Exercise Price per Share
Outstanding, beginning balance (in dollars per share)	$ 24.49
Options granted (in dollars per share)	56.95
Options exercised (in dollars per share)	11.32
Options canceled (in dollars per share)	31.22
Outstanding, ending balance (in dollars per share)	28.79	$ 24.49
Vested and exercisable (in dollars per share)	15.29
Vested and expected to vest (in dollars per share)	$ 28.23
Weighted- Average Remaining Contractual Term (Years) and Aggregate Intrinsic Value of Stock Options
Weighted-average remaining contractual term of stock options outstanding	6 years 11 months 1 day	7 years 7 months 10 days
Weighted-average remaining contractual term of stock options vested and exercisable	6 years 1 month 20 days
Weighted-average remaining contractual term of stock options vested and expected to vest	6 years 11 months 1 day
Aggregate intrinsic value of stock options outstanding	$ 646,394	$ 620,802
Aggregate intrinsic value of stock options outstanding vested and exercisable	296,738
Aggregate intrinsic value of stock options outstanding vested and expected to vest	$ 620,296