Net Loss - Summary of Computation of Basic and Diluted Net Income (Loss) Per Share (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]
Net loss	$ (3,804)	$ (3,960)	$ (1,159)	$ (8,732)
Deemed dividend for beneficial conversion feature on Series D-2 Preferred	0	0	(909)	0
Deemed dividend for antidilution adjustments to convertible preferred stock	0	0	(214)	0
Accretion of convertible preferred stock	0	0	(510)	0
Net loss attributable to common stock - basic	(3,804)	(3,960)	(2,792)	(8,732)
Derivative fair value adjustment	0	0	10,080	0
Net loss attributable to common stock - diluted	$ (3,804)	$ (3,960)	$ (12,872)	$ (8,732)
Weighted-average common shares outstanding - basic	8,504,785	335,938	4,703,278	335,930
Incremental shares from assumed exercise of common stock warrants	0	0	273,687	0
Weighted-average of outstanding common stock - diluted	8,504,785	335,938	4,976,965	335,930
Basic	$ (0.45)	$ (11.79)	$ (0.59)	$ (25.99)
Diluted	$ (0.45)	$ (11.79)	$ (2.59)	$ (25.99)