Fair Value of Financial Instruments - Summary of Fair Value Assessment of Warrant Liability Inputs using Black Sholes Option Pricing Model (Details) (USD $)	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2014	Mar. 25, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value of Series B/C/D Stock and Series E Stock shares on grant date or measurement date	$ 0.13us-gaap_SharePrice	$ 0.13us-gaap_SharePrice	$ 0.13us-gaap_SharePrice
Expected risk-free interest rate	1.70%	1.60%	1.20%
Expected volatility	75.00%	75.00%	70.00%
Expected term	6 years 6 months	7 years	4 years 1 month 6 days
Expected dividend yield	0.00%	0.00%
Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value of Series B/C/D Stock and Series E Stock shares on grant date or measurement date		$ 0.14	$ 0.14	$ 0.01
Exercise price		$ 0.01	$ 0.01	$ 0.01
Expected risk-free interest rate	0.40%
Expected volatility	55.00%
Expected term	8 months 12 days
Expected dividend yield			0.00%
Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Fair value of Series B/C/D Stock and Series E Stock shares on grant date or measurement date		$ 0.22	$ 0.22	$ 0.12
Exercise price		$ 0.346	$ 0.346	$ 0.346
Expected risk-free interest rate	1.90%
Expected volatility	75.00%
Expected term	9 years 4 months 24 days
Expected dividend yield			8.00%

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Agreed upon price for the exchange of the underlying asset.

+ 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

+ Details

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- Definition

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

+ Details

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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

+ Details

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- Definition

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

+ References

+ Details

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- Definition

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

+ References

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- Definition

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

+ References

No definition available.

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