Stock Incentive Plans - Intrinsic Value Calculated Based on Grant Date Fair Value (Detail) - $ / shares	1 Months Ended		3 Months Ended	4 Months Ended	5 Months Ended	7 Months Ended		12 Months Ended
	Sep. 30, 2014	Oct. 31, 2013	Dec. 31, 2014	Dec. 31, 2015	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of options granted	300,000	14,450	235,650	900,084	92,600	39,300	82,815	992,684	574,950	97,265
Intrinsic value calculated based on grant date fair value, Exercise price	$ 4.30		$ 4.25	$ 1.00	$ 2.43	$ 7.69	$ 6.60
Intrinsic value calculated based on grant date fair value, Exercise price	5.20	$ 12.11	4.41	1.35	4.04	11.29	7.97
Intrinsic value calculated based on grant date fair value, Intrinsic value per share	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0