Stockholders Equity - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended	9 Months Ended				1 Months Ended			1 Months Ended
	Aug. 31, 2012	Sep. 30, 2012	Sep. 30, 2012	Aug. 06, 2012	May 31, 2012	Dec. 31, 2011	Aug. 31, 2012 If the Stockholder Approval has not been obtained as of the close of business	Aug. 06, 2012 Series A Junior Participating Preferred Stock	Aug. 06, 2012 Rights	May 31, 2012 Senior Convertible Notes Due 2018	May 09, 2012 Senior Convertible Notes Due 2018
Schedule of Capitalization, Equity [Line Items]
Convertible notes exchanged, warrants issued to purchase common stock										4,000,000
Convertible notes exchanged, warrants exercise price									2.50		1.863
Warrant liability, fair value		$ 8,100,000	$ 8,100,000		$ 5,300,000
Realized gain on change in valuation of warrant liability		$ (6,577,000)	$ (2,785,000)
Dividends declared, number of preferred share purchase right for each outstanding share of common Stock				1
Common stock, par value		$ 0.01	$ 0.01			$ 0.01
Preferred stock, par value		$ 0.01	$ 0.01			$ 0.01		$ 0.01
Number of preferred stock that each right entitles the holder to purchase								0.001
Preferred stock purchase right expiration date	Aug. 06, 2015						Aug. 06, 2013