Equity Award Plans - Summary of Activity for Restricted Common Stock, RSAs and RSUs and Summary of Information Related to Unvested Restricted Common Stock, RSAs and RSUs and those Expected to Vest (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Unvested balance, beginning (in shares)	20,054	8,341	3,602
Granted (in shares)	12,711	16,876	6,734
Vested (in shares)	(6,222)	(2,783)	(1,482)
Cancelled (in shares)	(6,660)	(2,380)	(809)
Unvested balance, ending (in shares)	19,883	20,054	8,341
Granted in acquisitions (in shares)			296
Expected to vest (in shares)	5,584
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Unvested balance, beginning, weighted average grant date fair value (usd per share)	$ 33.68	$ 39.57	$ 27.20
Weighted average grant date fair value, granted (usd per share)	13.76	32.25	42.12
Weighted average grant date fair value, vested (usd per share)	33.99	35.66	16.04
Weighted average grant date fair value, cancelled (usd per share)	27.17	41.11	40.93
Unvested balance, ending, weighted average grant date fair value (usd per share)	22.23	$ 33.68	39.57
Weighted average grant date fair value, granted in acquisitions (usd per share)			$ 26.44
Weighted average grant date fair value, expected to vest (usd per share)	$ 20.22
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Unvested balance, weighted-average remaining contractual term	1 year 6 months
Expected to vest, weighted-average remaining contractual term	2 years
Unvested balance, aggregate intrinsic value	$ 236,605
Expected to vest, aggregate intrinsic value	$ 66,445