Net Loss Per Share - Summary of Computation of Basic and Diluted Net Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income (loss) attributable to common stock - basic:
Loss from continuing operations	$ (7,529)	$ (4,200)	$ (19,950)	$ (2,225)
Deemed dividend for beneficial conversion feature on Series D-2 Preferred	0	0	0	(909)
Deemed dividend for antidilution adjustments to convertible preferred stock	0	0	0	(214)
Accretion of convertible preferred stock	0	0	0	(510)
Allocation of net income to convertible preferred stockholders	0	0	0	0
Loss from continuing operations attributable to common stock - basic	(7,529)	(4,200)	(19,950)	(3,858)
Income (loss) from discontinued operations attributable to common stock	(826)	396	(4,285)	1,066
Net loss attributable to common stockholders - basic	(8,355)	(3,804)	(24,235)	(2,792)
Income (loss) attributable to common stock - diluted:
Derivative fair value adjustment	0	0	0	(10,080)
Loss from continuing operations attributable to common stock - diluted	(7,529)	(4,200)	(19,950)	(13,938)
Net loss attributable to common stockholders - diluted	$ (8,355)	$ (3,804)	$ (24,235)	$ (12,872)
Weighted-average common shares outstanding:
Weighted-average common shares outstanding - basic	13,904,331	8,504,785	11,576,498	4,703,278
Allocation of common stock warrants as participating securities	0	0	0	273,687
Weighted-average common shares outstanding - diluted	13,904,331	8,504,785	11,576,498	4,976,965
Income (loss) per share - basic:
Continuing operations, per basic share (USD per share)	$ (0.54)	$ (0.50)	$ (1.72)	$ (0.82)
Discontinued operations, per basic share (USD per share)	(0.06)	0.05	(0.37)	0.23
Net loss per share - basic (USD per share)	(0.60)	(0.45)	(2.09)	(0.59)
Income (loss) per share - diluted:
Continuing operations, per diluted share (USD per share)	(0.54)	(0.50)	(1.72)	(2.80)
Discontinued operations, per diluted share (USD per share)	(0.06)	0.05	(0.37)	0.21
Net income (loss) per share - diluted (USD per share)	$ (0.60)	$ (0.45)	$ (2.09)	$ (2.59)