The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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The amount of identifiable intangible assets recognized as of the acquisition date.

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Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

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Goodwill and Purchased Intangible Assets - Purchased Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 18, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Purchased intangible assets, net	$ 133.0		$ 133.0			$ 130.2
Amortization of intangible assets	$ 4.1	$ 4.8	$ 12.6	$ 12.9
Cyphort
Finite-Lived Intangible Assets [Line Items]
Intangible acquired					$ 15.4