Net Loss per Share - Outstanding Options, Warrants and Convertible Preferred Stock Excluded from Computation of Diluted Net Loss per Share (Detail) - shares	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Convertible Preferred Stock (as converted)
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share		2,127,463
Options to purchase common stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	1,045,060	593,663
Warrant | Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share	219,723	931
Warrant | Convertible Preferred Stock (as converted)
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share		136,908