Fair Value Measurement - Roll Forward for Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3) (Detail) (USD $)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Add change in fair value of warrants	$ (347,330)us-gaap_FairValueAdjustmentOfWarrants	$ (326,624)us-gaap_FairValueAdjustmentOfWarrants
Less repayments of principal	(1,681,664)
Outstanding Warrants [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2014	1,684,551
Add change in fair value of warrants	347,330
Balance at March 31, 2015	2,031,881
Balance at March 31, 2015	2,031,881
Loan Payable [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2014	15,020,417
Add amortization of discount	34,043
Less repayments of principal	(1,681,664)
Balance at March 31, 2015	13,372,796
Current portion	4,097,837
Non-current portion	9,274,959
Balance at March 31, 2015	$ 13,372,796

Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value Current

No definition available.

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- Definition

Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value Noncurrent

+ References

No definition available.

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- Definition

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 1A

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-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

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-Subparagraph (SX 210.5-03.8)

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 8

-Article 5

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- Definition

Amount of the total principal payments made during the annual reporting period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

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-Number 210

-Section 02

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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)

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 480

-SubTopic 10

-Section 25

-Paragraph 13

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- Definition

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

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