Common Stock Warrant Liability - Additional Information (Detail) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	1 Months Ended	9 Months Ended		40 Months Ended
	Jul. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2013 After Reverse Split	Jul. 31, 2011 After Reverse Split	Apr. 30, 2011 After Reverse Split
Class Of Warrant Or Right [Line Items]
Proceeds from issuance of warrants		$ 60,000	$ 60,000	$ 200,000
Warrant issued to purchase common stock		1.5
Aggregate purchase price of common stock warrant		$ 300,000
Common stock warrants expiration date		2020-06
Common stock warrants exercise price					10.30	6.64	6.90
Warrant vested upon issuance		20.00%		20.00%
Common stock warrants annual vesting percentage on each anniversary date		20.00%		20.00%
Common stock warrants percentage vested		80.00%		80.00%
Common stock issued as purchase consideration	0.3
Price per share of common stock issued						$ 6.64
Percentage of common stock warrants waiving protection provisions	79.30%