Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 02, 2017	Apr. 03, 2016
Income Statement [Abstract]
Revenue	$ 134,942	$ 96,205
Cost of revenue	28,225	20,968
Gross margin	106,717	75,237
Research, development, and engineering expenses	22,770	20,555
Selling, general, and administrative expenses	46,521	38,338
Operating income	37,426	16,344
Foreign currency gain (loss)	(263)	(100)
Investment income	2,012	1,137
Other income (expense)	270	207
Income before income tax expense	39,445	17,588
Income tax expense (benefit)	(6,210)	2,703
Net Income	$ 45,655	$ 14,885
Net income per weighted-average common and common-equivalent share:
Basic (in dollars per share)	$ 0.53	$ 0.18
Diluted (in dollars per share)	$ 0.51	$ 0.17
Weighted-average common and common-equivalent shares outstanding:
Basic (in shares)	86,323	84,943
Diluted (in shares)	89,177	86,541
Cash dividends per common share	$ 0.075	$ 0.070