Condensed Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 28, 2019	Jul. 29, 2018	Jul. 28, 2019	Jul. 29, 2018
Income Statement [Abstract]
Net sales	$ 137,146	$ 163,211	$ 268,500	$ 293,640
Cost of sales	52,262	63,087	102,341	122,047
Gross profit	84,884	100,124	166,159	171,593
Operating costs and expenses:
Selling, general and administrative	39,875	33,529	78,252	74,935
Product development and engineering	25,553	28,079	52,652	54,278
Intangible amortization	3,908	6,480	9,051	13,441
Changes in the fair value of contingent earn-out obligations	0	(900)	(2,161)	(900)
Total operating costs and expenses	69,336	67,188	137,794	141,754
Operating income	15,548	32,936	28,365	29,839
Interest expense	(2,597)	(2,200)	(5,064)	(4,390)
Non-operating income, net	1,213	542	2,256	732
Income before taxes and equity in net gains (losses) of equity method investments	14,164	31,278	25,557	26,181
Provision (benefit) for income taxes	8,966	6,082	6,654	(11,428)
Net income before equity in net gains (losses) of equity method investments	5,198	25,196	18,903	37,609
Equity in net gains (losses) of equity method investments	168	(27)	(243)	(58)
Net income	$ 5,366	$ 25,169	$ 18,660	$ 37,551
Earnings per share:
Basic (in dollars per share)	$ 0.08	$ 0.38	$ 0.28	$ 0.57
Diluted (in dollars per share)	$ 0.08	$ 0.37	$ 0.28	$ 0.55
Weighted average number of shares used in computing earnings per share:
Basic (in shares)	66,519	66,063	66,312	66,194
Diluted (in shares)	67,746	68,880	67,814	68,428