Derivative Financial Instruments - Changes in Fair Value Inputs and Assumptions Related to Derivative Warrants (Detail) (Warrant Derivatives [Member], USD $)	6 Months Ended
Jun. 30, 2014	Jun. 30, 2013
Warrant Derivatives [Member]
Derivative [Line Items]
Beginning balance	$ 923,580	$ 3,826,619
Changes in fair value inputs and assumptions reflected in income	(323,736)	(660,569)
Ending balance	$ 599,844	$ 3,166,050

Amount of increase (decrease) 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.

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=36462937&loc=d3e19207-110258

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration