Interest Expense on Convertible Senior Notes (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012
Debt Instrument
Contractual interest expense	$ 2,114	$ 2,114	$ 6,388	$ 6,413
Amortization of the discount component and debt issue fees	4,221	3,710	12,266	10,781
Total interest expense on the convertible debt	$ 6,335	$ 5,824	$ 18,654	$ 17,194

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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