MidCap Secured Loan Facility - Schedule Showing Allocation of Secured Loan Facility to Notes Payable and Midcap Warrants (Detail) (USD $)	3 Months Ended
Mar. 31, 2014
Debt [Line Items]
Total proceeds	$ 20,000,000
Note payable [Member]
Debt [Line Items]
Total proceeds	19,013,648
Midcap warrant [Member]
Debt [Line Items]
Total proceeds	$ 986,352

The cash inflow from borrowings supported by a written promise to pay an obligation that is collateralized (backed by pledge, mortgage or other lien in the entity's assets).

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3255-108585

Name:	us-gaap_ProceedsFromSecuredNotesPayable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration