Determination of Net Loss Per Common Share (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Determination of net loss per common share [Line Items]
Net loss	$ (3,203,778)	$ (1,461,713)	$ (6,478,212)	$ (4,857,021)
Deemed dividend attributable to preferred stockholders in connection with embedded beneficial conversion features	0	0	(4,140,446)	(2,955,668)
Return of capital to common shareholders attributable to the repurchase of the Series A-4 preferred shares and related embedded beneficial conversion feature	0	0	589,751	0
Net loss applicable to common stockholders	$ (3,203,778)	$ (1,461,713)	$ (10,028,907)	$ (7,812,689)
Net loss per common share applicable to common stockholders, basic and diluted	$ (0.26)	$ (0.19)	$ (1.02)	$ (1.18)
Weighted average number of common shares outstanding, basic and diluted	12,133,984	7,853,292	9,879,905	6,602,626