Stock-Based Compensation Expense - Summary of Restricted Stock and Restricted Stock Unit Activity (Detail)	3 Months Ended
	Mar. 31, 2017 $ / shares shares
Restricted Stock [Member]
Shares
Unvested balance, Beginning balance (in shares) | shares	585,004
Granted (in shares) | shares	0
Vested (in shares) | shares	(78,441)
Forfeited (in shares) | shares	(860)
Unvested balance, Ending balance (in shares) | shares	505,703
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share) | $ / shares	$ 18.05
Granted (in dollars per share) | $ / shares	0.00
Vested (in dollars per share) | $ / shares	19.05
Forfeited (in dollars per share) | $ / shares	23.01
Ending Balance (in dollars per share) | $ / shares	$ 17.89
Restricted Stock Units (RSUs) [Member]
Shares
Unvested balance, Beginning balance (in shares) | shares	734,577
Granted (in shares) | shares	1,308,940
Vested (in shares) | shares	(48,312)
Forfeited (in shares) | shares	(40,554)
Unvested balance, Ending balance (in shares) | shares	1,954,651
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars per share) | $ / shares	$ 13.47
Granted (in dollars per share) | $ / shares	13.83
Vested (in dollars per share) | $ / shares	13.21
Forfeited (in dollars per share) | $ / shares	12.73
Ending Balance (in dollars per share) | $ / shares	$ 13.73