Change in Value of Warrant and Derivative Liability Unobservable Inputs Financial Instrument Reconciliation (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2013
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value at December 31, 2012	$ 835
Fair value of derivative liability recorded on measurement date	3,124
Fair value at December 31, 2013	6,602
Derivative Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Change in fair value recorded as a loss from change in fair value of financial liability	4,406
Adjustment to fair value of derivative liability related to early conversion of notes	(1,616)
Warrant Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Change in fair value recorded as a loss from change in fair value of financial liability	$ (147)

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Amount of transfers of financial instrument classified as a liability into level 3 of the fair value hierarchy.

+ 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 (c)(3)

-URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258

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Amount of transfers of financial instrument classified as a liability out of level 3 of the fair value hierarchy.

+ References

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Amount of gain (loss) recognized on the income statement for financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ 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 (c)(1)

-URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258

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Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ 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 (c)

-URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258

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