Segment and Geographic Information - Schedule of sales by geographic regions (Details) - USD ($) $ in Thousands	3 Months Ended
	Jan. 02, 2021	Dec. 28, 2019
Geographic information [Line Items]
Net sales	$ 326,053	$ 320,771
United States
Geographic information [Line Items]
Net sales	71,527	77,885
Total foreign countries sales
Geographic information [Line Items]
Net sales	254,526	242,886
South Korea
Geographic information [Line Items]
Net sales	71,838	60,056
China
Geographic information [Line Items]
Net sales	61,459	58,588
Japan
Geographic information [Line Items]
Net sales	23,339	22,351
Asia-Pacific, other
Geographic information [Line Items]
Net sales	27,411	22,162
Germany
Geographic information [Line Items]
Net sales	29,285	30,445
Europe, other
Geographic information [Line Items]
Net sales	28,531	34,513
Rest of World
Geographic information [Line Items]
Net sales	$ 12,663	$ 14,771