Warrants (Details) - $ / shares	1 Months Ended		12 Months Ended
	Dec. 31, 2015	Jul. 31, 2015	Dec. 31, 2015	Nov. 20, 2014	Nov. 19, 2014	Apr. 30, 2014	Apr. 30, 2013	Dec. 31, 2009	Dec. 31, 2007
Class of Stock [Line Items]
Warrants outstanding (in shares)									24,538
Warrants exercise price (in dollars per share)									$ 0.0978
Secured Loan Arrangement
Class of Stock [Line Items]
Warrants outstanding (in shares)						376,691
Warrants exercise price (in dollars per share)						$ 2.3229	$ 2.3229
B
Class of Stock [Line Items]
Warrants outstanding (in shares)								33,742
Warrants exercise price (in dollars per share)								$ 1.8908
E
Class of Stock [Line Items]
Warrants outstanding (in shares)				429,440
Warrants exercise price (in dollars per share)				$ 0.0163
Liquidation preference to liquidation value in the agreement (as a percent)				1.00%	2.00%
Common stock
Class of Stock [Line Items]
Closing price (in dollars per share)	$ 11.57		$ 11.57
Conversion into common shares (in shares)			31,397,000
Common stock | B
Class of Stock [Line Items]
Common stock issued for each warrant (in shares)		1
Conversion into common shares (in shares)	28,227
Common stock | E
Class of Stock [Line Items]
Conversion into common shares (in shares)		429,042