Condensed Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 27, 2019	Oct. 28, 2018	Oct. 27, 2019	Oct. 28, 2018
Income Statement [Abstract]
Net sales	$ 141,011	$ 173,550	$ 409,511	$ 467,190
Cost of sales	54,763	66,988	157,104	189,035
Gross profit	86,248	106,562	252,407	278,155
Operating costs and expenses:
Selling, general and administrative	33,795	39,587	112,047	114,522
Product development and engineering	26,670	27,147	79,322	81,425
Intangible amortization	3,770	6,480	12,821	19,921
Changes in the fair value of contingent earn-out obligations	(152)	(8,519)	(2,313)	(9,419)
Total operating costs and expenses	64,083	64,695	201,877	206,449
Operating income	22,165	41,867	50,530	71,706
Interest expense	(2,183)	(2,355)	(7,247)	(6,745)
Non-operating income, net	644	1,182	2,900	1,914
Investment impairments	0	(30,000)	0	(30,000)
Income before taxes and equity in net gains (losses) of equity method investments	20,626	10,694	46,183	36,875
Provision (benefit) for income taxes	3,379	(1,454)	10,033	(12,882)
Net income before equity in net gains (losses) of equity method investments	17,247	12,148	36,150	49,757
Equity in net gains (losses) of equity method investments	352	17	109	(41)
Net income	$ 17,599	$ 12,165	$ 36,259	$ 49,716
Earnings per share:
Basic (in dollars per share)	$ 0.27	$ 0.18	$ 0.55	$ 0.75
Diluted (in dollars per share)	$ 0.26	$ 0.18	$ 0.54	$ 0.73
Weighted average number of shares used in computing earnings per share:
Basic (in shares)	66,387	66,014	66,337	66,134
Diluted (in shares)	67,318	68,731	67,630	68,549