Income Taxes - Components of Net Deferred Tax Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred Tax Liabilities [Line Items]
In-process research and development not subject to future amortization for tax purposes	$ 5,053	$ 5,053
Gross deferred tax liability	$ 5,053	$ 5,053