CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2016	Jul. 03, 2015	Jul. 01, 2016	Jul. 03, 2015
Income Statement [Abstract]
Revenue	$ 97,734	$ 96,494	$ 188,050	$ 191,108
Cost of revenue	56,238	55,149	109,662	109,757
Gross profit	41,496	41,345	78,388	81,351
Operating expenses:
Research and development and engineering	8,016	7,840	16,068	16,055
Selling, general and administrative	20,198	20,922	41,385	42,990
Amortization of purchased intangible assets	1,979	1,852	4,087	3,741
Restructuring, acquisition and divestiture related costs	3,705	416	6,663	2,853
Total operating expenses	33,898	31,030	68,203	65,639
Operating income from continuing operations	7,598	10,315	10,185	15,712
Interest income (expense), net	(1,205)	(1,375)	(2,390)	(2,772)
Foreign exchange transaction gains (losses), net	707	(3,153)	790	(2,636)
Other income (expense), net	270	20,034	1,013	20,763
Income from continuing operations before income taxes	7,370	25,821	9,598	31,067
Income tax provision	2,499	6,310	2,821	8,110
Income from continuing operations	4,871	19,511	6,777	22,957
Loss from discontinued operations, net of tax		(13)		(13)
Consolidated net income	$ 4,871	$ 19,498	$ 6,777	$ 22,944
Earnings per common share from continuing operations:
Basic	$ 0.14	$ 0.56	$ 0.20	$ 0.66
Diluted	0.14	0.56	0.19	0.66
Loss per common share from discontinued operations:
Basic		0.00		0.00
Diluted		0.00		0.00
Earnings per common share:
Basic	0.14	0.56	0.20	0.66
Diluted	$ 0.14	$ 0.56	$ 0.19	$ 0.66
Weighted average common shares outstanding—basic	34,734	34,630	34,696	34,567
Weighted average common shares outstanding—diluted	34,887	35,029	34,870	35,014