Stockholders' Equity - Warrants - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended
	Feb. 28, 2017	Mar. 31, 2018	Mar. 31, 2017
Sale Of Stock [Line Items]
Change in fair value of warrant liability		$ (433,392)	$ 3,072,747
July 2016 Financing [Member]
Sale Of Stock [Line Items]
Unregistered warrants to purchase of common stock	526,315
Conversion of stock, shares issued	211,860
Weighted average exercise price of warrants	$ 2.41
Reclassification of warrant liability to Additional Paid-in Capital	$ 1,400,000
Warrant Amendments [Member]
Sale Of Stock [Line Items]
Unregistered warrants to purchase of common stock		2,449,129
Reclassification of warrant liability to Additional Paid-in Capital		$ 3,300,000
Change in fair value of warrant liability		$ 433,000
Amendment date		2018-03