Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Stockholders' equity
Series I redeemable preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Series I redeemable preferred stock, shares issued	0	35,541
Series I redeemable preferred stock, shares outstanding	0	35,541
Series I redeemable preferred stock, liquidation preference	$ 167	$ 167
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	50,000,000	50,000,000
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	2,539,859	1,505,773
Common stock, shares outstanding	2,539,847	1,505,761
Treasury stock, shares	12	12
Series A Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
liquidation preference	$ 0.0001	$ 0.0001
Series C Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares issued	0	1
Preferred stock, shares outstanding	0	1
liquidation preference	$ 0.0001	$ 0.0001
Series D Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares issued	4,725	4,725
Preferred stock, shares outstanding	4,725	4,725
liquidation preference	$ 0.0001	$ 0.0001
Series D-1 Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares issued	834	834
Preferred stock, shares outstanding	834	834
liquidation preference	$ 0.0001	$ 0.0001
Series F-1 Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
liquidation preference	$ 0.0001	$ 0.0001
Series H Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares issued	381,967	439,043
Preferred stock, shares outstanding	381,967	439,043
liquidation preference	$ 83.50	$ 83.50
Series J Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
liquidation preference	$ 0.0001	$ 0.0001
Series K Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares issued	1,240	0
Preferred stock, shares outstanding	1,240	0
liquidation preference	$ 1,000	$ 1,000