Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Oct. 02, 2020	Jul. 03, 2020	Apr. 03, 2020	Jan. 03, 2020	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 28, 2018	Oct. 02, 2020	Sep. 27, 2019	Sep. 28, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 147,249	$ 137,267	$ 126,424	$ 119,097	$ 112,248	$ 108,306	$ 128,465	$ 150,689	$ 530,037	$ 499,708	$ 570,398
United States
Disaggregation of Revenue [Line Items]
Revenues									217,474	239,510	272,951
China
Disaggregation of Revenue [Line Items]
Revenues									192,989	132,329	159,763
Asia Pacific, excluding China
Disaggregation of Revenue [Line Items]
Revenues									84,997	80,136	79,581
Other Countries
Disaggregation of Revenue [Line Items]
Revenues									34,577	47,733	58,103
Telecom
Disaggregation of Revenue [Line Items]
Revenues									209,477	180,938	222,940
Industrial & Defense
Disaggregation of Revenue [Line Items]
Revenues									194,506	204,638	185,360
Data Center
Disaggregation of Revenue [Line Items]
Revenues									$ 126,054	$ 114,132	$ 162,098