Stockholders' Equity (Deficit) (Details)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Weighted-average volatility	102.86%	101.00%	89.13%
Risk-free interest rate	1.98%	1.31%	1.10%
Weighted-average expected life (in years)	6 years 7 months 6 days	6 years 7 months 6 days	6 years 2 months 12 days
Dividend yield	0.00%	0.00%	0.00%

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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).

+ References

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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- Definition

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.

+ References

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- Definition

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

+ References

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- Definition

Weighted average expected volatility of stock price.

+ References

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