Stock Based Compensation - Summary of Stock Option Plan (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock Options, Number of Options
Outstanding, Beginning balance (in shares)	1,507,765	1,325,029	1,250,829
Granted (in shares)	1,146,643	400,258	95,700
Exercised (in shares)	(7,786)	0	0
Cancelled (in shares)	(215,275)	(217,522)	(21,500)
Outstanding, Ending balance (in shares)	2,431,347	1,507,765	1,325,029
Options exercisable (in shares)	633,059	267,168	7,963
Stock Options, Weighted Average Exercise Price
Outstanding, Beginning balance (usd per share)	$ 21.07	$ 22.35	$ 22.45
Granted (usd per share)	11.61	18.78	20.91
Exercised (usd per share)	18.73	0.00	0.00
Cancelled (usd per share)	15.76	24.62	22.00
Outstanding, Ending balance (usd per share)	17.09	21.07	22.35
Weighted Average Exercise Price, options exercisable (usd per share)	$ 21.50	$ 21.98	$ 20.93
Unamortized value of unvested stock options (net of estimated forfeitures) (usd)	$ 7,317	$ 8,135	$ 10,092
Weighted-average period that expense is expected to be recognized	2 years 3 months 18 days	2 years 7 months 6 days	3 years 4 months 24 days
Weighted-average remaining contractual life (in years) for options outstanding	7 years 8 months 12 days	7 years 10 months 24 days	8 years 3 months 18 days
Weighted-average remaining contractual life (in years) for options exercisable	6 years 1 month 6 days	7 years 3 months 18 days	8 years 6 months