Business Combination - Purchase Price Allocation (Details) - USD ($) $ in Millions	Mar. 30, 2019	Oct. 01, 2018	Sep. 29, 2018	Jul. 31, 2018
Purchase Price Allocation [Line Items]
Goodwill	$ 2,564.5		$ 2,533.2
Faxitron
Purchase Price Allocation [Line Items]
Cash				$ 2.4
Accounts receivable				4.0
Inventory				6.0
Other assets				3.1
Accounts payable and accrued expenses				(4.9)
Deferred revenue				(1.9)
Long-term debt				(3.3)
Deferred income taxes, net				(11.5)
Goodwill				42.4
Purchase Price				89.5
Faxitron | Developed technology
Purchase Price Allocation [Line Items]
Identifiable intangible assets				44.9
Faxitron | In-process research and development
Purchase Price Allocation [Line Items]
Identifiable intangible assets				5.5
Faxitron | Customer relationships
Purchase Price Allocation [Line Items]
Identifiable intangible assets				0.5
Faxitron | Trade names
Purchase Price Allocation [Line Items]
Identifiable intangible assets				$ 2.3
Focal Therapeutics
Purchase Price Allocation [Line Items]
Cash		$ 2.2
Accounts receivable		2.0
Inventory		8.3
Other assets		0.8
Accounts payable and accrued expenses		(5.6)
Long-term debt		(2.5)
Deferred income taxes, net		(12.7)
Goodwill		30.4
Purchase Price		120.1
Focal Therapeutics | Developed technology
Purchase Price Allocation [Line Items]
Identifiable intangible assets		83.1
Focal Therapeutics | In-process research and development
Purchase Price Allocation [Line Items]
Identifiable intangible assets		11.4
Focal Therapeutics | Trade names
Purchase Price Allocation [Line Items]
Identifiable intangible assets		$ 2.7