Anti-dilutive Common Stock Equivalents Excluded from Calculation of Diluted Net Income Per Common Share (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive common stock equivalents excluded from calculation of diluted net income per common share	30,680,040	7,542,875	19,373,107	3,552,749
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive common stock equivalents excluded from calculation of diluted net income per common share	867,135	576,746	822,769	406,540
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive common stock equivalents excluded from calculation of diluted net income per common share	18,889,103	4,978,892	11,771,953	2,436,336
Unvested Restricted Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive common stock equivalents excluded from calculation of diluted net income per common share	0	15,493	405	16,512
Convertible Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive common stock equivalents excluded from calculation of diluted net income per common share	10,923,802	1,971,744	6,777,980	693,361