Restructuring Costs - Narrative (Details) ft² in Thousands, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 29, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 29, 2019 USD ($)	Jun. 30, 2018 USD ($)	Dec. 30, 2017 USD ($) ft² Employee
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 0	$ 569	$ 0	$ 1,339
Restructuring Plan 2017
Restructuring Cost and Reserve [Line Items]
Restructuring costs				1,339	$ 1,920
Restructuring Plan 2017 \| Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring costs				(55)	148
Restructuring Plan 2017 \| Relocation Of Machinery And Equipment And Administrative Offices
Restructuring Cost and Reserve [Line Items]
Restructuring costs				1,018	1,318
Restructuring Plan 2017 \| Employee Retention, Facility Closing, And Other Closure Costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs				$ 376	$ 454
Restructuring Plan 2017 \| United States
Restructuring Cost and Reserve [Line Items]
Manufacturing facility square footage (in sqft) \| ft²					160
Number of positions eliminated related to restructuring (employee) \| Employee					4
Restructuring Plan 2017 \| Sweden
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated related to restructuring (employee) \| Employee					6