Fair Value of Financial Assets and Liabilities - Derivative Instruments (Valuation Assumptions for Warrants) (Details) - $ / shares		3 Months Ended	12 Months Ended
		Mar. 31, 2016	Dec. 31, 2015
Fair Value Assumptions and Methodology for Assets and Liabilities [Line Items]
Common stock closing price		$ 3.94
Warrants Through 2011 [Member]
Fair Value Assumptions and Methodology for Assets and Liabilities [Line Items]
Volatility	[1]	108.00%	112.05%
Expected term (years)	[1]	8 months 23 days	11 months 23 days
Risk-free interest rate	[1]	0.48%	0.64%
Dividend yield	[1]	0.00%	0.00%
Exercise price	[1]	$ 23.00	$ 23.00
Common stock closing price	[1]	$ 3.94	$ 3.98

[1] See Note 7 - Warrants below for further description of the respective series of warrants.