Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 03, 2021	Apr. 04, 2020	Apr. 03, 2021	Apr. 04, 2020
Income Statement [Abstract]
Net sales	$ 373,982	$ 293,147	$ 700,035	$ 613,918
Cost of sales	232,957	199,036	439,014	410,554
Gross profit	141,025	94,111	261,021	203,364
Operating expenses:
Research and development	32,007	29,794	60,228	58,474
Selling, general and administrative	72,662	61,307	146,890	129,858
Merger and acquisition costs	231,996		231,996
Goodwill and other impairment charges	0	451,025	0	451,025
Amortization of intangible assets	596	1,296	1,193	2,728
Total operating expenses	337,261	543,422	440,307	642,085
Loss from operations	(196,236)	(449,311)	(179,286)	(438,721)
Other income (expense):
Interest income	110	370	272	637
Interest expense	(4,512)	(4,423)	(8,989)	(8,517)
Other—net	1,876	(1,610)	3,902	(817)
Total other expense, net	(2,526)	(5,663)	(4,815)	(8,697)
Loss before income taxes	(198,762)	(454,974)	(184,101)	(447,418)
Benefit from income taxes	(40,547)	(36,061)	(26,030)	(34,298)
Net loss	$ (158,215)	$ (418,913)	$ (158,071)	$ (413,120)
Net loss per share:
Basic (in USD per share)	$ (6.49)	$ (17.39)	$ (6.50)	$ (17.19)
Diluted (in USD per share)	$ (6.49)	$ (17.39)	$ (6.50)	$ (17.19)
Shares used in computation:
Basic (shares)	24,389	24,095	24,326	24,033
Diluted (shares)	24,389	24,095	24,326	24,033