Fair Value of Financial Assets and Liabilities - Derivative Instruments (Valuation Assumptions Used for Series B Convertible Stock) (Details) - $ / shares	3 Months Ended	12 Months Ended
Mar. 31, 2016	Dec. 31, 2015
Common stock closing price	$ 3.94
Series B redeemable convertible preferred stock [Member]
Volatility	108.00%
Dividend yield	0.00%	0.00%
Exercise price	$ 7.00	$ 7.00
Common stock closing price	$ 3.94	$ 3.98
Series B redeemable convertible preferred stock [Member] \| Minimum [Member]
Volatility		108.00%
Expected term (years)	15 days	6 months
Risk-free interest rate	0.18%	0.49%
Series B redeemable convertible preferred stock [Member] \| Maximum [Member]
Volatility		117.00%
Expected term (years)	9 months	2 years 6 months
Risk-free interest rate	0.49%	1.19%

Agreed upon price for the exchange of the underlying asset.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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Expected dividends to be paid to holders of the underlying shares or financial instruments (expressed as a percentage of the share or instrument's price).

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Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

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Risk-free interest rate assumption used in valuing an instrument.

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Price of a single share of a number of saleable stocks of a company.

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