Stock Incentive Plans - Summary of Non-vested Options (Detail) - $ / shares	1 Months Ended	4 Months Ended		5 Months Ended	12 Months Ended
	Sep. 30, 2016	Apr. 30, 2016	Jul. 31, 2015	Jul. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Options
Options, Granted	892,500	51,120	900,084	92,600	943,620	992,684
Weighted-average exercise price
Weighted-average exercise price, Granted					$ 0.63	$ 1.40
Weighted-average exercise price, Cancelled					$ 8.96	$ 10.02
Non-vested Options [Member]
Options
Options, Non-vested, Beginning balance		1,251,961			1,251,961	628,733
Options, Granted					943,620	992,684
Options, Vested					(330,115)	(200,402)
Options, Cancelled					(375,635)	(169,054)
Options, Non-vested, Ending balance					1,489,831	1,251,961
Weighted-average exercise price
Weighted-average exercise price, Beginning balance		$ 2.23			$ 2.23	$ 5.93
Weighted-average exercise price, Granted					0.63	1.40
Weighted-average exercise price, Vested					2.81	6.64
Weighted-average exercise price, Cancelled					2.51	5.86
Weighted-average exercise price, Ending balance					$ 1.02	$ 2.23