Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Income Statement [Abstract]
Revenue	$ 259,739	$ 147,952	$ 567,585	$ 391,431
Cost of revenue	62,360	32,749	128,056	88,930
Gross margin	197,379	115,203	439,529	302,501
Research, development, and engineering expenses	26,078	18,603	72,225	58,829
Selling, general, and administrative expenses	61,054	42,072	160,093	123,125
Operating income	110,247	54,528	207,211	120,547
Foreign currency gain (loss)	(127)	(607)	(574)	(377)
Investment income	2,475	2,047	6,625	4,631
Other income (expense)	(445)	374	(344)	803
Income from continuing operations before income tax expense	112,150	56,342	212,918	125,604
Income tax expense (benefit) on continuing operations	9,802	2,667	8,843	14,030
Net income from continuing operations	102,348	53,675	204,075	111,574
Net income from discontinued operations	0	0	0	(255)
Net Income	$ 102,348	$ 53,675	$ 204,075	$ 111,319
Basic earnings per weighted-average common and common-equivalent share:
Net income from continuing operations	$ 1.18	$ 0.63	$ 2.36	$ 1.31
Net income (loss) from discontinued operations	0.00	0.00	0.00	0.00
Net income	1.18	0.63	2.36	1.31
Diluted earnings per weighted-average common and common-equivalent share:
Net income from continuing operations	1.14	0.61	2.28	1.29
Net income (loss) from discontinued operations	0.00	0.00	0.00	(0.01)
Net income	$ 1.14	$ 0.61	$ 2.28	$ 1.28
Weighted-average common and common-equivalent shares outstanding:
Basic	86,617	85,460	86,526	85,167
Diluted	89,677	87,346	89,562	86,805
Cash dividends per common share	$ 0.085	$ 0.075	$ 0.245	$ 0.22