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Related Party Transactions (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
	Apr. 26, 2019	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019	Dec. 28, 2019
Related Party Transaction
Cost method investments		$ 0.4		$ 0.4
MWT
Related Party Transaction
Loss on disposal	$ 2.6
Powersem
Related Party Transaction
Ownership percentage (percent)		45.00%		45.00%
Revenue from related parties		$ 0.3	$ 0.1	$ 0.7	$ 0.2
Purchase from related party		0.8	0.9	1.0	1.7
Receivable from related parties		0.1		0.1		$ 0.0
Payables to related parties		$ 0.2		$ 0.2		0.2
EB Tech
Related Party Transaction
Ownership percentage (percent)		19.00%		19.00%
Revenue from related parties		$ 0.0	0.0	$ 0.0	0.0
Purchase from related party		0.0	0.1	0.0	0.2
Receivable from related parties		0.0		0.0		0.0
Payables to related parties		$ 0.0		$ 0.0		0.0
ATEC
Related Party Transaction
Ownership percentage (percent)		24.00%		24.00%
Revenue from related parties		$ 0.0	0.0	$ 0.0	0.0
Purchase from related party		1.6	$ 2.3	3.4	$ 3.8
Receivable from related parties		0.0		0.0		0.0
Payables to related parties		$ 0.1		$ 0.1		$ 0.1