Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 03, 2016	Apr. 05, 2015
Income Statement [Abstract]
Revenue	$ 96,205	$ 101,373
Cost of revenue	20,968	22,344
Gross margin	75,237	79,029
Research, development, and engineering expenses	20,555	16,986
Selling, general, and administrative expenses	38,338	39,933
Operating income	16,344	22,110
Foreign currency gain (loss)	(100)	659
Investment income	1,137	850
Other income (expense)	207	(310)
Income from continuing operations before income tax expense	17,588	23,309
Income tax expense on continuing operations	2,703	3,837
Net income from continuing operations	14,885	19,472
Pretax income from discontinued operations	0	1,030
Net Income	$ 14,885	$ 20,502
Basic earnings per weighted-average common and common-equivalent share:
Net income from continuing operations	$ 0.18	$ 0.22
Net income from discontinued operations	0.00	0.02
Net income	0.18	0.24
Diluted earnings per weighted-average common and common-equivalent share:
Net income from continuing operations	0.17	0.22
Net income from discontinued operations	0.00	0.01
Net income	$ 0.17	$ 0.23
Weighted-average common and common-equivalent shares outstanding:
Basic	84,943	86,764
Diluted	86,541	88,749
Cash dividends per common share	$ 0.07	$ 0