Accrued Liabilities - Schedule of Accrued Expenses (Detail) - USD ($)	Sep. 30, 2015	Dec. 31, 2014
Accrued Liabilities Current [Abstract]
Payroll and employee-related costs	$ 479,891	$ 6,560
Research and development costs	2,180,320	26,260
Professional fees	236,005	37,813
Other	106,463	4,525
Total accrued expenses	$ 3,002,679	$ 75,158