Summary of Deferred Tax Assets and Liabilities (Detail) (USD $) In Millions, unless otherwise specified	Dec. 30, 2012	Dec. 25, 2011
Schedule of Deferred Tax Assets and Liabilities [Line Items]
Net operating loss carryforwards	$ 51.3	$ 40.4
Reserves and accruals	39.0	41.8
Tax credit and capital allowance carryovers	87.4	94.2
Plant and equipment		0.2
Unrealized loss in other comprehensive income		4.0
Total gross deferred tax assets	177.7	180.6
Valuation allowance	(154.5)	(171.1)
Net deferred tax assets	23.2	9.5
Plant and equipment	(0.4)
Unrealized gain in other comprehensive income	(2.7)
Capitalized research expenses and intangibles	(3.1)	(3.7)
Total deferred tax liabilities	(6.2)	(3.7)
Net deferred tax assets (liabilities)	$ 17.0	$ 5.8