Stock-Based Compensation - Summary of Stock Options (Detail) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($) $ / shares shares
2013 Stock Incentive Plan
Stock Options
Stock options, outstanding (in options) | shares	9,607,431
Stock options, granted (in options) | shares	110,433
Stock options, forfeited (in options) | shares	(106,555)
Stock options, expired (in options) | shares	(190,281)
Stock options, outstanding (in options) | shares	9,421,028
Stock options, exercisable (in options) | shares	4,643,602
Stock options, expected to vest after March 31, 2017 (in options) | shares	4,777,426
Stock options, exercisable as of March 31, 2017 and expected to vest thereafter (in options) | shares	9,421,028
Weighted- Average Exercise Price
Weighted - average exercise price, outstanding (in usd per share)	$ 12.79
Weighted - average exercise price, granted (in usd per share)	8.15
Weighted - average exercise price, forfeited (in usd per share)	12.40
Weighted - average exercise price, expired (in usd per share)	13.10
Weighted - average exercise price, outstanding (in usd per share)	12.74
Weighted - average exercise price exercisable at March 31, 2017 (in usd per share)	13.21
Weighted - average exercise price, expected to vest after March 31, 2017 (in usd per share)	12.28
Weighted - average exercise price, exercisable as of March 31, 2017 and expected to vest thereafter (in usd per share)	$ 12.74
Weighted - average remaining contractual term, outstanding	7 years 8 months 5 days
Weighted - average remaining contractual term, exercisable at March 31, 2017	6 years 10 months 6 days
Weighted - average remaining contractual term, expected to vest after March 31, 2017	8 years 5 months 27 days
Weighted - average remaining contractual term, exercisable as of March 31, 2017 and expected to vest thereafter	7 years 8 months 5 days
Estimated fair value of the Company's common stock (in dollars per share)	$ 7.85
2011 Stock Incentive Plan
Stock Options
Stock options, outstanding (in options) | shares	1,931,830
Stock options, granted (in options) | shares	14,724
Stock options, exercised (in options) | shares	(90,320)
Stock options, forfeited (in options) | shares	(128,677)
Stock options, outstanding (in options) | shares	1,727,557
Stock options, exercisable (in options) | shares	552,672
Stock options, expected to vest after March 31, 2017 (in options) | shares	1,174,885
Stock options, exercisable as of March 31, 2017 and expected to vest thereafter (in options) | shares	1,727,557
Weighted- Average Exercise Price
Weighted - average exercise price, outstanding (in usd per share)	$ 8.73
Weighted - average exercise price, granted (in usd per share)	8.15
Weighted - average exercise price, exercised (in usd per share)	6.96
Weighted - average exercise price, forfeited (in usd per share)	9.67
Weighted - average exercise price, outstanding (in usd per share)	8.75
Weighted - average exercise price exercisable at March 31, 2017 (in usd per share)	7.01
Weighted - average exercise price, expected to vest after March 31, 2017 (in usd per share)	9.57
Weighted - average exercise price, exercisable as of March 31, 2017 and expected to vest thereafter (in usd per share)	$ 8.75
Weighted - average remaining contractual term, outstanding	4 years 10 months 10 days
Weighted - average remaining contractual term, exercisable at March 31, 2017	3 years 7 months 17 days
Weighted - average remaining contractual term, expected to vest after March 31, 2017	5 years 5 months 9 days
Weighted - average remaining contractual term, exercisable as of March 31, 2017 and expected to vest thereafter	4 years 10 months 10 days
Aggregate intrinsic value, outstanding | $	$ 1,227
Aggregate intrinsic value, exercisable at March 31, 2017 | $	871
Aggregate intrinsic value, expected to vest after March 31, 2017 | $	356
Aggregate intrinsic value, exercisable as of March 31, 2017 and expected to vest thereafter | $	$ 1,227
Estimated fair value of the Company's common stock (in dollars per share)	$ 7.85