Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Jan. 26, 2020	Jan. 27, 2019	Jan. 28, 2018
Income Statement [Abstract]
Net sales	$ 547,512	$ 627,196	$ 587,847
Cost of sales	210,828	250,174	235,876
Gross profit	336,684	377,022	351,971
Operating costs and expenses:
Selling, general and administrative	163,106	145,246	148,146
Product development and engineering	107,368	109,047	105,070
Intangible amortization	16,546	26,649	27,867
Loss (gain) on disposition of business operations	0	0	375
Changes in the fair value of contingent earn-out obligations	(2,345)	(9,419)	3,892
Total operating costs and expenses	284,675	271,523	285,350
Operating income	52,009	105,499	66,621
Interest expense	(9,106)	(9,202)	(7,963)
Non-operating income, net	2,893	3,823	3,348
Investment impairments	(1,211)	(30,000)	(4,250)
Income before taxes and equity in net gains (losses) of equity method investments	44,585	70,120	57,756
Provision for income taxes	12,828	355	22,853
Net income before equity in net gains (losses) of equity method investments	31,757	69,765	34,903
Equity in net gains (losses) of equity method investments	109	(126)	(254)
Net income	31,866	69,639	34,649
Net loss attributable to noncontrolling interest	(5)	0	0
Net income attributable to common stockholders	$ 31,871	$ 69,639	$ 34,649
Earnings per share:
Basic (in dollars per share)	$ 0.48	$ 1.06	$ 0.52
Diluted (in dollars per share)	$ 0.47	$ 1.02	$ 0.51
Weighted average number of shares used in computing earnings per share:
Basic (in shares)	66,263,000	65,982,000	66,027,000
Diluted (in shares)	67,418,000	68,481,000	67,605,000