Fair Value Measurements - Summary of Reconciliation of Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Detail) - Fair Value Measurement, Recurring [Member] - Warrant Liability [Member]	9 Months Ended
	Sep. 30, 2017 USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2016	$ 4,095,019
Change in fair value upon re-measurement	3,354,973
Reclassification to Additional Paid-in Capital due to warrant exercise	(1,399,091)
Balance at September 30, 2017	$ 6,050,901