Assumptions Used to Estimate Warrant Values (Detail) (Warrant, USD $)	0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended
Jun. 03, 2013 First Issuance	Dec. 31, 2013 First Issuance	Nov. 15, 2013 Second Issuance	Dec. 31, 2013 Second Issuance
Class of Warrant or Right [Line Items]
Class A Common Stock: Closing Market Price	$ 2.94	$ 3.02	$ 3.21	$ 3.02
Market Price Volatility	102.93%	95.00%	95.00%	95.00%
Expected average term of warrants, in years	5 years	4 years 6 months	5 years 6 months	5 years 6 months
Expected dividend yield	0.00%	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=25499696&loc=d3e19207-110258

+ 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

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

+ References

+ Details

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