Warrant Liability - Assumptions Used for Black-Scholes Option Pricing Model (Detail) (USD $)	3 Months Ended	9 Months Ended		9 Months Ended	12 Months Ended
Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Warrant Agreement 2008 [Member]	Dec. 31, 2012 Warrant Agreement 2008 [Member]
Class of Warrant or Right [Line Items]
Expected life (years)						7 months 6 days	1 year 4 months 24 days
Risk-free interest rate						0.10%	0.20%
Expected volatility						40.20%	108.20%
Expected dividend yield						0.00%	0.00%
Fair value of warrant liability	$ 8,420,954		$ 8,420,954		$ 9,265,365	$ 0	$ 44,628
Change in fair value of warrant liability	$ 143,511	$ 11,239,465	$ (425,570)	$ 9,974,685		$ (44,628)

Fair Value Of Warrant Liability

No definition available.

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- Definition

Amount of expense (income) related to adjustment to fair value of warrant liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 480

-SubTopic 10

-Section 25

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=6939902&loc=d3e20148-110875

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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

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

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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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