Subsequent Events - Additional Information (Detail) (USD $)			0 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Aug. 13, 2013 Subsequent Event [Member]	Jul. 26, 2013 Subsequent Event [Member]	Jul. 17, 2013 Subsequent Event [Member]	Aug. 13, 2013 Subsequent Event [Member] IPO [Member]
Subsequent Event [Line Items]
Shareholders approved a reverse stock split description				1-for-1.75
Lease term terminates					31-12-2017
Total annual rent payments, 2013	$ 1,416,000				$ 94,000
Total annual rent payments, 2014	2,918,000				370,000
Total annual rent payments, 2015	2,492,000				464,000
Total annual rent payments, 2016	1,863,000				478,000
Total annual rent payments, 2017	927,000				492,000
Shares of common stock						11,499,998
Shares of common stock issued to underwriters						1,499,999
IPO price per share						$ 16.00
Aggregate net proceeds			$ 168,300,000
Shares of common stock			79,705,130
Number of authorized shares of common stock	185,000,000	160,000,000	200,000,000
Number of authorized shares of preferred stock			25,000,000
Shares of common stock reserved for issuance			7,000,000