Equity - Stock Option Activity (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015
Number of Options
Beginning balance (in shares)	1,847,669
Granted (in shares)	1,271,391
Exercised (in shares)	(319,079)
Canceled (in shares)	(30,722)
Ending balance (in shares)	2,769,259
Vested, at end of period (in shares)	830,911
Vested and expected to vest, at end of period (in shares)	2,538,150	[1]
Weighted Average Exercise Price
Beginning balance (in USD per share)	$ 26.99
Granted (in USD per share)	$ 33.98
Exercised (in USD per share)	$ 15.35
Canceled (in USD per share)	$ 28.11
Ending balance (in USD per share)	$ 31.53
Vested, at end of period (in USD per share)	$ 25.27
Aggregate Intrinsic Value
Exercised	$ 6,958	[2]
Ending balance	12,063
Vested, at end of period	8,401	[3]
Vested and expected to vest, at end of period	$ 11,696	[3]

[1] Represents the number of vested options as of March 31, 2015, plus the number of unvested options expected to vest as of March 31, 2015, based on the unvested options outstanding at March 31, 2015, adjusted for the estimated forfeiture.

[2] The aggregate intrinsic value was calculated based on the positive difference between the estimated fair value of the Company’s common stock as of the date of exercise and the exercise price of the underlying options.

[3] The aggregate intrinsic value was calculated based on the positive difference between the estimated fair value of the Company’s common stock as of March 31, 2015, and the exercise price of the underlying options.