Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		99 Months Ended		3 Months Ended	9 Months Ended		3 Months Ended		0 Months Ended		1 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Initial Public Offer [Member]	Sep. 30, 2013 Initial Public Offer [Member]	Aug. 09, 2013 Initial Public Offer [Member]	Sep. 30, 2013 Initial Public Offer [Member] Stock Options [Member]	Sep. 30, 2013 Initial Public Offer [Member] Grants to Non-Employees [Member]	Oct. 30, 2013 Subsequent Event [Member]	Oct. 08, 2013 Subsequent Event [Member]	Oct. 31, 2013 Subsequent Event [Member]
Class of Stock [Line Items]
Reverse split of common stock													1-for-5
Common stock, offering price per share							$ 10.00					$ 10.00		$ 10.00
Stock-based compensation	$ 1,130,000	$ 108,000	$ 1,531,000	$ 292,000	$ 2,561,000		$ 900,000	$ 900,000		$ 200,000	$ 700,000
Unrecognized stock-based compensation expense							13,600,000	13,600,000
Warrant liability	$ 11,485,000		$ 11,485,000		$ 11,485,000	$ 2,456,000	$ 1,400,000	$ 1,400,000	$ 2,000,000