Business Combinations, Intangible Assets Acquired (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Sep. 18, 2017	Dec. 06, 2016	Aug. 09, 2016	Apr. 01, 2016
Cyphort
Business Acquisition [Line Items]
Finite-lived intangible assets:			$ 15.4
Intangible assets			15.4
Cyphort | IPR&D
Business Acquisition [Line Items]
Indefinite-lived intangible assets:			0.0
Cyphort | Existing technology
Business Acquisition [Line Items]
Acquired intangible asset, weighted average estimated useful life (in years)	5 years
Finite-lived intangible assets:			15.4
Cyphort | Customer relationships
Business Acquisition [Line Items]
Finite-lived intangible assets:			0.0
Cyphort | Other
Business Acquisition [Line Items]
Finite-lived intangible assets:			$ 0.0
AppFormix
Business Acquisition [Line Items]
Finite-lived intangible assets:				$ 20.3
Intangible assets				20.3
AppFormix | IPR&D
Business Acquisition [Line Items]
Indefinite-lived intangible assets:				0.0
AppFormix | Existing technology
Business Acquisition [Line Items]
Acquired intangible asset, weighted average estimated useful life (in years)	5 years
Finite-lived intangible assets:				20.1
AppFormix | Customer relationships
Business Acquisition [Line Items]
Acquired intangible asset, weighted average estimated useful life (in years)	1 year
Finite-lived intangible assets:				0.2
AppFormix | Other
Business Acquisition [Line Items]
Finite-lived intangible assets:				$ 0.0
Aurrion, Inc
Business Acquisition [Line Items]
Finite-lived intangible assets:					$ 0.0
Intangible assets					49.0
Aurrion, Inc | IPR&D
Business Acquisition [Line Items]
Indefinite-lived intangible assets:					49.0
Aurrion, Inc | Existing technology
Business Acquisition [Line Items]
Finite-lived intangible assets:					0.0
Aurrion, Inc | Customer relationships
Business Acquisition [Line Items]
Finite-lived intangible assets:					0.0
Aurrion, Inc | Other
Business Acquisition [Line Items]
Finite-lived intangible assets:					$ 0.0
BTI Systems, Inc
Business Acquisition [Line Items]
Finite-lived intangible assets:						$ 43.3
Intangible assets						43.3
BTI Systems, Inc | IPR&D
Business Acquisition [Line Items]
Indefinite-lived intangible assets:						0.0
BTI Systems, Inc | Existing technology
Business Acquisition [Line Items]
Acquired intangible asset, weighted average estimated useful life (in years)		8 years
Finite-lived intangible assets:						37.1
BTI Systems, Inc | Customer relationships
Business Acquisition [Line Items]
Acquired intangible asset, weighted average estimated useful life (in years)		8 years
Finite-lived intangible assets:						5.3
BTI Systems, Inc | Other
Business Acquisition [Line Items]
Acquired intangible asset, weighted average estimated useful life (in years)		1 year
Finite-lived intangible assets:						$ 0.9