Equity Incentive Plans - Summary of Stock Option and RSU Activity Under Plan (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Available for Grant, Beginning Balance	469,531	9,919,107	9,407,975
Shares Available for Grant, Additional options reserved	3,426,428	1,064,046	3,796,342
Shares Available for Grant, Granted	(3,345,899)	(11,854,941)	(4,011,973)
Shares Available for Grant, Exercised
Shares Available for Grant, Cancelled	1,170,445	1,341,319	726,763
Shares Available for Grant, Ending Balance	23,318,526	469,531	9,919,107
Number of Options, Beginning Balance	25,007,776	15,806,663	13,738,122
Number of Options, Granted	2,643,821	11,854,941	4,011,973
Number of Options, Exercised	(3,852,673)	(1,312,439)	(1,216,669)
Number of Options, Cancelled	(1,157,982)	(1,341,389)	(726,763)
Number of Options, Ending Balance	22,640,942	25,007,776	15,806,663
Weighted Average Exercise Price, Beginning Balance	$ 21.20	$ 13.35	$ 8.62
Weighted Average Exercise Price, Granted	$ 74.17	$ 31.18	$ 27.49
Weighted Average Exercise Price, Exercised	$ 21.42	$ 12.52	$ 5.41
Weighted Average Exercise Price, Cancelled	$ 36.47	$ 25.51	$ 15.26
Weighted Average Exercise Price, Ending Balance	$ 26.70	$ 21.20	$ 13.35
Number of RSUs, Beginning Balance
Number of RSUs, Granted	702,078
Number of RSUs, Exercised
Number of RSUs, Cancelled	(12,463)
Number of RSUs, Released	(12,031)
Number of RSUs, Ending Balance	677,584
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Grant Date Fair Value, Beginning Balance
Weighted Average Grant Date Fair Value, Granted	$ 155.51
Weighted Average Grant Date Fair Value, Exercised
Weighted Average Grant Date Fair Value, Cancelled	$ 154.92
Weighted Average Grant Date Fair Value, Released	$ 160.98
Weighted Average Grant Date Fair Value, Ending Balance	$ 155.41