Income Taxes - Schedule of Change in Valuation Allowance (Detail) (USD $)	3 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Valuation allowance	$ 63,625,186	$ 60,312,726
Change in valuation allowance	$ 3,312,460

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

Name:	us-gaap_DeferredTaxAssetsValuationAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant