Stock Purchase Warrants - Additional Information (Detail) (USD $)	9 Months Ended					9 Months Ended
	Sep. 30, 2014 Warrant [Member]	Sep. 30, 2014 Series B Preferred Stock [Member]	Nov. 20, 2013 Series B Preferred Stock [Member]	Aug. 14, 2013 Series B Preferred Stock [Member]	Dec. 20, 2012 Series B Preferred Stock [Member]	Sep. 30, 2014 Series A and Series B Preferred Stock [Member]	Sep. 30, 2014 Series A Preferred Stock [Member]	Apr. 12, 2012 Series A Preferred Stock [Member]
Class of Warrant or Right [Line Items]
Warrants to purchase shares	60,000		9,692	96,921	96,921			2,042
Exercise price of warrants per share	$ 10.00		$ 5.16	$ 5.16	$ 5.16			$ 12.24
Conversion of preferred stock into common stock		(1,316,681)				74,001	(980,391)
Warrants exercisable date	May 01, 2015
Warrants expiration date	May 01, 2019