Fair Value Measurements (Details 3) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Changes in fair value of the financial liabilities
Decrease in fair value included in change in fair value of common stock warrants	$ 2,300,000	$ 8,800,000	$ 2,400,000
Using Significant Unobservable Inputs (Level 3) [Member]
Changes in fair value of the financial liabilities
Balance at beginning of year	5,176,319	370,926	2,774,850
Decrease in fair value included in change in fair value of common stock warrants	(2,316,420)	(8,827,658)	(2,403,924)
Balance at end of year	2,859,899	5,176,319	370,926
Warrant Issued in January 2011 [Member] \| Warrants Issued [Member] \| Using Significant Unobservable Inputs (Level 3) [Member]
Changes in fair value of the financial liabilities
Record fair value of warrants issued	0	11,727,372	0
Warrant Issued in December 2011 [Member] \| Warrants Issued [Member] \| Using Significant Unobservable Inputs (Level 3) [Member]
Changes in fair value of the financial liabilities
Record fair value of warrants issued	$ 0	$ 1,905,679	$ 0

Amount of gain (loss) recognized in earnings, arising from liabilities measured at fair value on a recurring basis using unobservable inputs (level 3).

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

Issues that have taken place during the period in relation to liabilities measured at fair value and categorized within Level 3 of the fair value hierarchy.

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- Definition

This element represents a liability measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances.

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