Net Loss per Share - Reconcilation of Numerator and Denominator Used in Computing Basic and Diluted Net Loss per Share (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Numerator:
Net loss	$ (16,453,918)	$ (18,960,017)
Denominator:
Weighted-average shares outstanding-basic and diluted	27,523,463	10,597,318
Net loss per share, basic and diluted	$ (0.60)	$ (1.79)