Condensed consolidated financial statement details - Intangible Assets and Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying value	$ 51,066		$ 50,501
Accumulated amortization	(47,156)		(45,269)
Net carrying value	3,910		5,232
Intangible Assets, Gross (Excluding Goodwill)	51,081		50,516
Intangible assets, net	3,925		5,247
Indefinite-lived Intangible Assets [Roll Forward]
Amortization of intangible assets	1,900	$ 2,100
Goodwill	146,459		146,459
Indefinite-Lived Trademarks	$ 15		$ 15

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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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Carrying amount (original costs adjusted for previously recognized amortization and impairment) as of the balance sheet date for the rights acquired through registration of a trademark to gain or protect exclusive use of a business name, symbol or other device or style for a projected indefinite period of benefit.

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Amount before accumulated amortization of intangible assets, excluding goodwill.

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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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