Issuance of Preferred Stock - Additional Information (Detail) - USD ($)		9 Months Ended
	Jan. 12, 2015	Sep. 30, 2015	Dec. 31, 2014
Temporary Equity [Line Items]
Conversion of convertible notes payable to preferred stock		$ 200,000
Convertible preferred stock redeemable period		5 years
Deferred financing costs			$ 66,187
Series C Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares issued	4,344,567
Redeemable convertible preferred stock conversion in cash	$ 36,900,000
Conversion of convertible notes payable to preferred stock	$ 200,000
Deferred financing costs			$ 66,187
Series A Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares issued	1,426,353
Series B Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares issued	2,647,102
Series A and Series B Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Fair value on convertible preferred stock, inducement	$ 4,798,194