Schedule of Geographic Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2020	Jun. 28, 2019	Jul. 03, 2020	Jun. 28, 2019
Segment Reporting Information [Line Items]
Revenue	$ 144,728	$ 155,145	$ 300,196	$ 312,331
United States
Segment Reporting Information [Line Items]
Revenue	54,524	62,010	113,729	126,770
Germany
Segment Reporting Information [Line Items]
Revenue	22,148	18,838	45,381	42,315
Rest of Europe
Segment Reporting Information [Line Items]
Revenue	30,713	35,971	63,798	66,741
China
Segment Reporting Information [Line Items]
Revenue	17,472	15,392	32,876	30,500
Rest of Asia-Pacific
Segment Reporting Information [Line Items]
Revenue	17,842	20,702	39,542	41,149
Other Countries
Segment Reporting Information [Line Items]
Revenue	$ 2,029	$ 2,232	$ 4,870	$ 4,856