Guarantees (Details) (USD $)	3 Months Ended
	Apr. 28, 2013		Apr. 29, 2012
Estimated product warranty liabilities
Balance at beginning of period (1)	$ 14,874,000	[1]	$ 18,406,000	[1]
Additions	1,418,000		1,679,000
Deductions (2)	(1,459,000)	[2]	(3,015,000)	[2]
Balance at end of period	14,833,000		17,070,000
Incremental repair and replacement costs for the weak die/packaging material set	9,600,000		13,200,000
Payments related to warranty accrual	$ 500,000		$ 1,200,000

[1] Includes $9.6 million and $13.2 million for the three months ended April 28, 2013 and April 29, 2012, respectively, related to warranty accrual associated with incremental repair and replacement costs from a weak die/packaging material set.

[2] Includes $0.5 million and $1.2 million for the three months ended April 28, 2013 and April 29, 2012, respectively, in payments related to the warranty accrual associated with incremental repair and replacement costs from a weak die/packaging material set.