Condensed Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 26, 2014	Oct. 27, 2013	Oct. 26, 2014	Oct. 27, 2013
Net sales	$ 148,890	$ 141,026	$ 427,491	$ 468,443
Cost of sales	59,564	57,615	171,860	187,037
Gross profit	89,326	83,411	255,631	281,406
Operating costs and expenses:
Selling, general and administrative	31,692	30,849	94,935	98,958
Product development and engineering	28,401	31,948	84,387	99,632
Intangible amortization	6,423	7,349	19,292	22,416
Intangible asset impairments	0	0	0	2,600
Restructuring charge	0	0	1,001	0
Total operating costs and expenses	66,516	70,146	199,615	223,606
Operating income	22,810	13,265	56,016	57,800
Interest expense, net	(1,462)	(1,818)	(4,437)	(16,462)
Non-operating income (expense), net	216	(259)	(407)	(1,264)
Income before taxes	21,564	11,188	51,172	40,074
Provision (benefit) for taxes	3,941	(1,265)	7,784	(6,268)
Net income	$ 17,623	$ 12,453	$ 43,388	$ 46,342
Earnings per share:
Basic (in dollars per share)	$ 0.26	$ 0.18	$ 0.65	$ 0.69
Diluted (in dollars per share)	$ 0.26	$ 0.18	$ 0.64	$ 0.67
Weighted average number of shares used in computing earnings per share:
Basic (in shares)	67,162	67,792	67,223	67,454
Diluted (in shares)	67,654	68,871	67,791	68,819