Goodwill and Intangible Assets - Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	6 Months Ended
Apr. 03, 2021	Apr. 04, 2020
Goodwill [Roll Forward]
Goodwill, beginning of period	$ 101,317
Impairment charges	0	$ (327,203)
Goodwill, end of period	101,953
OEM Laser Sources
Goodwill [Roll Forward]
Goodwill, beginning of period	101,317
Translation adjustments	636
Goodwill, end of period	$ 101,953
Industrial Lasers & Systems
Goodwill [Roll Forward]
Impairment charges		$ (327,200)

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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Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of loss from the write-down of an asset representing the 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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