Summary of Fair Values of Assets and Liabilities Assumed (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Jan. 17, 2012 Patents [Member]	Jan. 17, 2012 Equipment And Leasehold Improvements
Business Acquisition [Line Items]
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ 467	$ 346		$ 201,730
Finite-Lived Intangible Assets, Accumulated Amortization	$ 4	$ 0	$ 2,290