Intangible Assets - Summary of Activity in Intangible Assets and Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
Sep. 27, 2019	Sep. 28, 2018	Sep. 29, 2017
Goodwill and Intangible Assets [Roll Forward]
Beginning balance	$ 773,307	$ 811,703
Fair value adjustment		0
Currency translation adjustments	270	889
Impairments of intangible assets	(344,625)
Ending balance	428,952	773,307	$ 811,703
In-process research and development
Goodwill and Intangible Assets [Roll Forward]
Impairments of intangible assets			(4,400)
Trade name, indefinite lived
Goodwill and Intangible Assets [Roll Forward]
Beginning balance	3,400	3,400
Fair value adjustment		0
Currency translation adjustments	0	0
Impairments of intangible assets	0
Ending balance	3,400	3,400	3,400
Total Goodwill
Goodwill and Intangible Assets [Roll Forward]
Beginning balance	314,076	313,765
Fair value adjustment		2,790
Currency translation adjustments	651	81
Impairments of intangible assets	0
Ending balance	314,727	314,076	313,765
Acquired technology
Goodwill and Intangible Assets [Roll Forward]
Beginning balance	251,673	251,655
Fair value adjustment		0
Currency translation adjustments	270	18
Impairments of intangible assets	(72,261)
Ending balance	179,682	251,673	251,655
Customer relationships
Goodwill and Intangible Assets [Roll Forward]
Beginning balance	518,234	556,648
Fair value adjustment		0
Currency translation adjustments	0	871
Impairments of intangible assets	(272,364)
Ending balance	$ 245,870	518,234	$ 556,648
LR4 \| Disposal Group, Not Discontinued Operations
Goodwill and Intangible Assets [Roll Forward]
Increase (decrease) in intangible assets		(39,285)
Increase (decrease) in goodwill		(2,560)
LR4 \| Disposal Group, Not Discontinued Operations \| Trade name, indefinite lived
Goodwill and Intangible Assets [Roll Forward]
Increase (decrease) to indefinite lived intangible assets		0
LR4 \| Disposal Group, Not Discontinued Operations \| Acquired technology
Goodwill and Intangible Assets [Roll Forward]
Increase (decrease) in finite lived intangible assets		0
LR4 \| Disposal Group, Not Discontinued Operations \| Customer relationships
Goodwill and Intangible Assets [Roll Forward]
Increase (decrease) in finite lived intangible assets		$ (39,285)

Goodwill and Intangible Assets [Roll Forward]

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Increase (Decrease), Allocation To Disposal Group, Including Discontinued Operations, Finite Lived Intangible Assets, Noncurrent

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Increase (Decrease), Allocation To Disposal Group, Including Discontinued Operations, Goodwill

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Increase (Decrease), Allocation To Disposal Group, Including Discontinued Operations, Indefinite Lived Intangible Assets, Noncurrent

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Increase (Decrease), Allocation To Disposal Group, Including Discontinued Operations, Intangible Assets, Noncurrent

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- Definition

Amount of foreign currency translation gain (loss) which increases (decreases) assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount of increase (decrease) in carrying value of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Total loss recognized during the period from the impairment of goodwill plus the loss recognized in the period resulting from the impairment of the carrying amount of intangible assets, other than goodwill.

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Carrying amount of finite-lived intangible assets, indefinite-lived intangible assets and goodwill. Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Intangible assets are assets, not including financial assets, lacking physical substance.

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