Equity Award Plans - Summary of Activity under the 2006 Plan and 2013 Plan (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Equity [Abstract]
Number of Shares, Options Outstanding, Balance	4,314	3,000	2,486
Weighted Average Remaining Contractual Term, Options granted (in Years)	9 years 3 months 4 days	8 years 4 months 2 days	7 years 2 months 23 days
Number of Shares, Options granted	1,594	2,046	1,399
Weighted Average Remaining Contractual Term, Options exercised (in Years)
Number of Shares, Options exercised	(618)	(518)	(607)
Weighted Average Remaining Contractual Term, Options forfeited and cancelled (in Years)
Number of Shares, Options forfeited and cancelled	(435)	(214)	(278)
Weighted Average Remaining Contractual Term, Options Outstanding (in Years)	7 years 10 months 6 days	7 years 1 month 10 days	6 years 2 months 23 days	5 years 6 months 15 days
Number of Shares, Options Outstanding, Balance	4,855	4,314	3,000	2,486
Weighted Average Remaining Contractual Term, Options exercisable (in Years)	7 years 6 months 29 days
Weighted Average Exercise Price, Options Outstanding, Balance	$ 4.17	$ 1.71	$ 1.14
Number of Shares, Options exercisable, Balance	4,067
Weighted Average Remaining Contractual Term, Options vested (in Years)	6 years 9 months 11 days
Weighted Average Exercise Price, Options granted	$ 11.98	$ 7.48	$ 2.53
Number of Shares, Options vested, Balance	2,199
Weighted Average Remaining Contractual Term, Options vested and expected to vest (in Years)	7 years 9 months 18 days
Weighted Average Exercise Price, Options exercised	$ 2.42	$ 3.23	$ 1.31
Number of Shares, Options vested and expected to vest, Balance	4,637
Weighted Average Exercise Price, Options forfeited and cancelled	$ 8.60	$ 3.66	$ 1.65
Weighted Average Exercise Price, Options Outstanding, Balance	$ 6.56	$ 4.17	$ 1.71	$ 1.14
Aggregate Intrinsic Value, Options Outstanding, Balance	$ 34,439	$ 10,575	$ 3,174
Weighted Average Exercise Price, Options exercisable, Balance	$ 5.75
Weighted Average Exercise Price, Options vested, Balance	$ 3.32
Weighted Average Exercise Price, Options vested and expected to vest, Balance	$ 6.40
Aggregate Intrinsic Value, Options Outstanding, Balance	20,593	34,439	10,575	3,174
Aggregate Intrinsic Value, Options exercisable, Balance	19,974
Aggregate Intrinsic Value, Outstanding, Options vested, Balance	15,321
Aggregate Intrinsic Value, Outstanding, Options vested and expected to vest, Balance	$ 20,279