Summary of Significant Accounting Policies - Summary of Calculation of Basic and Diluted Net Loss Per Share (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Net loss attributable to common shareholders for basic net loss per share	$ (2,303,193)	$ (1,625,969)	$ (4,285,980)	$ (6,678,008)
Adjustment for loss from change in fair value of warrants		(429,702)		(429,702)
Net loss used for diluted net loss per share	$ (2,303,193)	$ (2,055,671)	$ (4,285,980)	$ (7,107,710)
Weighted-average shares used to compute basic net loss per share	16,425,468	15,343,325	15,926,253	14,435,818
Adjustment to reflect assumed exercise of warrants		77,629		38,815
Weighted-average shares used to compute diluted net loss per share	16,425,468	15,420,954	15,926,253	14,474,633
Basic	$ (0.14)	$ (0.11)	$ (0.27)	$ (0.46)
Diluted	$ (0.14)	$ (0.13)	$ (0.27)	$ (0.49)