Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	9 Months Ended
	Jul. 04, 2020	Jun. 29, 2019	Sep. 28, 2019
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	$ 69,490		$ 243,348
Accumulated Amortization	(45,485)		(158,535)
Net including IPRD	24,005		84,813
Amortization expense for intangible assets	(27,166)	$ (47,725)
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2020 (remainder)	2,918
2021	9,404
2022	3,186
2023	2,639
2024	1,854
2025	1,852
Thereafter	2,152
Net excluding IPRD	24,005
Existing technology
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	43,114		193,704
Accumulated Amortization	(32,181)		(131,429)
Net including IPRD	10,933		62,275
Impairment charges	27,700
Customer relationships
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	24,076		42,083
Accumulated Amortization	(12,503)		(21,512)
Net including IPRD	11,573		20,571
Impairment charges	6,200
Trade name
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	0		5,261
Accumulated Amortization	0		(5,138)
Net including IPRD	0		123
Production know-how
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	2,300		2,300
Accumulated Amortization	(801)		(456)
Net including IPRD	1,499		$ 1,844
Foreign exchange
Finite-Lived Intangible Assets, Net [Abstract]
Amortization expense for intangible assets	$ 1,800	$ (2,100)