CONDENSED CONSOLIDATED STATEMENTS OF NET (LOSS) INCOME (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Income Statement [Abstract]
Net sales	$ 307,337	$ 397,879	$ 653,433	$ 803,379
Cost of sales	208,238	256,071	430,622	506,343
Gross profit	99,099	141,808	222,811	297,036
Selling, general, and administrative expenses	53,981	57,666	108,367	120,621
Goodwill impairment charge	33,841	0	33,841	0
Research and development expenses	13,400	21,458	27,995	42,867
Amortization of intangibles	9,827	10,050	19,808	20,241
Total operating expenses	111,049	89,174	190,011	183,729
Operating (loss) income	(11,950)	52,634	32,800	113,307
Interest expense	5,855	5,589	11,273	11,275
Foreign exchange (gain) loss	(6,010)	(3,575)	(3,426)	668
Other (income) expense, net	(1,210)	(2,947)	39	1,358
(Loss) income before income taxes	(10,585)	53,567	24,914	100,006
Income taxes	(1,594)	9,775	9,261	19,225
Net (loss) income	$ (8,991)	$ 43,792	$ 15,653	$ 80,781
(Loss) income per share:
Basic (in dollars per share)	$ (0.37)	$ 1.77	$ 0.64	$ 3.27
Diluted (in dollars per share)	$ (0.37)	$ 1.75	$ 0.64	$ 3.23
Weighted-average shares and equivalent shares outstanding:
Basic (in shares)	24,312	24,740	24,353	24,729
Diluted (in shares)	24,312	24,983	24,520	24,998