Notes Payable - Statements of Fair Value Assumptions (Detail) (USD $)	0 Months Ended	12 Months Ended
May 07, 2013 Amended and Restated Convertible Notes [Member]	May 07, 2013 Amended and Restated Reimbursement Notes [Member]	May 07, 2013 Amended and Restated Bridge Notes [Member]	Dec. 31, 2013 Immediately Before [Member] Amended and Restated August 2009 Warrants [Member]	Dec. 31, 2013 Immediately Before [Member] Amended and Restated June 2010 Warrants [Member]	Dec. 31, 2013 Immediately Before [Member] Amended and Restated August 2010 Warrants [Member]	Dec. 31, 2013 Immediately Before [Member] Amended and Restated July 2011 Warrants [Member]	Dec. 31, 2013 Immediately Before [Member] MHR Restructuring Warrants [Member]	Dec. 31, 2013 Immediately After [Member] Amended and Restated August 2009 Warrants [Member]	Dec. 31, 2013 Immediately After [Member] Amended and Restated June 2010 Warrants [Member]	Dec. 31, 2013 Immediately After [Member] Amended and Restated August 2010 Warrants [Member]	Dec. 31, 2013 Immediately After [Member] Amended and Restated July 2011 Warrants [Member]	Dec. 31, 2013 Immediately After [Member] MHR Restructuring Warrants [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Closing stock price	$ 0.23	$ 0.23	$ 0.23	$ 0.24	$ 0.24	$ 0.24	$ 0.24		$ 0.23	$ 0.23	$ 0.23	$ 0.23	$ 0.23
Conversion price	$ 1.25	$ 0.50	$ 0.50	$ 0.70	$ 2.90	$ 1.26	$ 1.09		$ 0.50	$ 0.50	$ 0.50	$ 0.50	$ 0.50
Expected volatility	160.00%	184.00%	160.00%	175.71%	185.00%	182.34%	174.11%		143.31%	145.00%	143.31%	143.31%	143.31%
Remaining term (years)	4 years 4 months 21 days	11 months 19 days	4 years 4 months 21 days	1 year 3 months 15 days	1 year 3 months 15 days	2 years 3 months 22 days	3 years 2 months 1 day		6 years 2 months 1 day	6 years 2 months 1 day	6 years 2 months 1 day	6 years 2 months 1 day	6 years 2 months 1 day
Risk-free rate	0.63%	0.15%	0.63%	0.11%	0.14%	0.22%	0.36%		1.21%	1.01%	1.21%	1.21%	1.21%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%		0.00%	0.00%	0.00%	0.00%	0.00%

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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=25499696&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

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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

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