Stockholders' Equity - Warrants - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended
	Sep. 30, 2018	Mar. 31, 2018
Sale Of Stock [Line Items]
Change in fair value of warrant liability		$ 433,392
Warrant Amendments [Member]
Sale Of Stock [Line Items]
Unregistered warrants to purchase of common stock		2,449,129
Change in fair value of warrant liability		$ 433,000
Reclassification of warrant liability to Additional Paid-in Capital		$ 3,300,000
Amendment date		2018-03
Underwriters [Member]
Sale Of Stock [Line Items]
Unregistered warrants to purchase of common stock expired	84,000