Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2019	Sep. 30, 2018	Sep. 29, 2019	Sep. 30, 2018
Income Statement [Abstract]
Revenue	$ 183,325	$ 232,221	$ 555,856	$ 613,052
Cost of revenue	47,632	58,860	144,883	153,227
Gross margin	135,693	173,361	410,973	459,825
Research, development, and engineering expenses	28,115	29,700	86,436	87,664
Selling, general, and administrative expenses	64,486	65,817	199,542	196,266
Operating income	43,092	77,844	124,995	175,895
Foreign currency gain (loss)	(1,295)	(379)	(1,403)	(708)
Investment income	5,114	3,937	15,242	10,736
Other income (expense)	456	(129)	1,239	(98)
Income before income tax expense	47,367	81,273	140,073	185,825
Income tax expense	5,682	837	16,535	11,976
Net Income	$ 41,685	$ 80,436	$ 123,538	$ 173,849
Net income per weighted-average common and common-equivalent share:
Basic (usd per share)	$ 0.24	$ 0.47	$ 0.72	$ 1.01
Diluted (usd per share)	$ 0.24	$ 0.45	$ 0.71	$ 0.98
Weighted-average common and common-equivalent shares outstanding:
Basic (shares)	170,744	172,189	171,053	172,613
Diluted (shares)	174,449	177,245	175,164	178,021
Cash dividends per common share (usd per share)	$ 0.050	$ 0.045	$ 0.150	$ 0.135