Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Jan. 01, 2016	Jan. 02, 2015	Jan. 03, 2014
Income Statement [Abstract]
Sales	$ 800,414	$ 687,787	$ 663,945
Cost of sales	565,279	456,389	444,632
Gross profit	235,135	231,398	219,313
Operating expenses:
Selling, general and administrative expenses	102,530	90,602	88,107
Research, development and engineering costs, net	52,995	49,845	54,077
Other operating expenses, net	66,464	15,297	15,790
Total operating expenses	221,989	155,744	157,974
Operating income	13,146	75,654	61,339
Interest expense	33,513	4,252	11,261
(Gain) loss on cost and equity method investments, net	(3,350)	(4,370)	694
Other (income) expense, net	(1,317)	(807)	546
Income (loss) before provision for income taxes	(15,700)	76,579	48,838
Provision (benefit) for income taxes	(8,106)	21,121	12,571
Net income (loss)	$ (7,594)	$ 55,458	$ 36,267
Earnings (loss) per share:
Basic (in dollars per share)	$ (0.29)	$ 2.23	$ 1.51
Diluted (in dollars per share)	$ (0.29)	$ 2.14	$ 1.43
Weighted average shares outstanding:
Basic (in shares)	26,363	24,825	23,991
Diluted (in shares)	26,363	25,975	25,323
Comprehensive Income (Loss)
Net income (loss)	$ (7,594)	$ 55,458	$ 36,267
Foreign currency translation gain (loss)	(7,841)	(3,502)	1,521
Net change in cash flow hedges, net of tax	108	(1,359)	(382)
Defined benefit plan liability adjustment, net of tax	(20)	(374)	272
Other comprehensive income (loss)	(7,753)	(5,235)	1,411
Comprehensive income (loss)	$ (15,347)	$ 50,223	$ 37,678