Discontinued Operations - Schedule of Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2016	Jul. 05, 2015	Jul. 03, 2016	Jul. 05, 2015
Revenue and Expenses
Income (loss) from discontinued operations before income tax expense (benefit)	$ (255)	$ 198	$ (255)	$ 1,228
Significant Noncash Items
Capital expenditures			0	482
SISD | Discontinued Operations, Disposed of by Sale
Revenue and Expenses
Revenue	0	11,187	0	23,248
Cost of revenue	0	(5,765)	0	(11,291)
Research, development, and engineering expenses	0	(1,022)	0	(2,126)
Selling, general, and administrative expenses	0	(4,176)	0	(7,800)
Foreign currency gain (loss)	0	77	0	(177)
Operating income from discontinued operations	0	301	0	1,854
Gain (loss) on sale of discontinued operations	(404)	0	(404)	0
Income (loss) from discontinued operations before income tax expense (benefit)	(404)	301	(404)	1,854
Income tax expense (benefit) on discontinued operations	(149)	103	(149)	626
Net income (loss) from discontinued operations	(255)	198	(255)	1,228
Significant Noncash Items
Capital expenditures	0	171	0	482
Stock-based compensation expense	0	144	0	427
Depreciation expense	0	203	0	401
Amortization expense	$ 0	$ 82	$ 0	$ 165