Segment and Geographic Information - Schedule of sales by geographic regions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 04, 2020	Jun. 29, 2019	Jul. 04, 2020	Jun. 29, 2019
Geographic information [Line Items]
Net sales	$ 298,330	$ 339,170	$ 912,248	$ 1,095,176
United States
Geographic information [Line Items]
Net sales	65,094	82,913	215,236	251,122
Total foreign countries sales
Geographic information [Line Items]
Net sales	233,236	256,257	697,012	844,054
South Korea
Geographic information [Line Items]
Net sales	63,428	65,717	180,412	235,443
China
Geographic information [Line Items]
Net sales	52,837	57,519	148,407	152,134
Japan
Geographic information [Line Items]
Net sales	22,272	24,119	70,990	114,702
Asia-Pacific, other
Geographic information [Line Items]
Net sales	24,090	23,954	67,889	72,100
Germany
Geographic information [Line Items]
Net sales	28,650	32,809	90,485	111,646
Europe, other
Geographic information [Line Items]
Net sales	27,917	38,296	95,130	114,973
Rest of World
Geographic information [Line Items]
Net sales	$ 14,042	$ 13,843	$ 43,699	$ 43,056