The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives.

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

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Amount before accumulated depreciation of leased physical assets used in the normal conduct of business to produce goods and services.

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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Balance Sheet Details - Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2018
Property, Plant and Equipment [Line Items]
Depreciation	$ 6.0	$ 6.6
Amortization of intangible assets	0.8	0.9
SafeOp Surgical, Inc.
Property, Plant and Equipment [Line Items]
Business acquisition, intangible assets recorded			$ 21.6
Machinery and equipment
Property, Plant and Equipment [Line Items]
Capital Leased Assets Gross	$ 0.4	$ 0.4