Cash and Cash Equivalents - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Feb. 11, 2013	Jan. 31, 2013	Jul. 25, 2012
Cash and Cash Equivalents [Line Items]
Investment in savings account	$ 23,500,000
Percentage of interest recognized from savings account investment	0.16%
Interest income from savings account investment	14,985
Cash and cash equivalents, money market accounts	24,500	24,500
Percentage of interest recognized from money market fund	0.01%	0.01%
Interest income from money market fund		280
Convertible secured promissory notes, principal amount					4,085,000
Convertible secured promissory notes, proceeds amount required to be maintained in an account subject to deposit account control agreement					1,000,000
Restricted cash	$ 0	$ 1,000,000		$ 500,000
Number of common stock to be issued upon exercise of warrant			541,668	187,500	1,436,121