Pro Forma Consolidated Financial Information - Summary of Consolidated Results of Operations on Pro Forma Basis (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition Pro Forma Information [Abstract]
Pro forma revenue	$ 14,912,362	$ 4,222,482
Pro forma operating expenses	(19,289,332)	(6,674,316)
Pro forma net loss attributable to common stockholders	$ (9,169,887)	$ (4,584,219)