Accumulated Other Comprehensive Income (Loss) - Summary of Accumulated Other Comprehensive Income, Net of Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Oct. 02, 2020	Sep. 27, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 313,896	$ 668,675
Ending balance	300,146	313,896
Foreign currency translation loss, net of tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	4,330	2,637
Other comprehensive income	458	1,693
Ending balance	4,788	4,330
Other Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	28	(449)
Ending balance	221	28
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	4,358	2,188
Ending balance	5,009	4,358
Unrealized loss on short-term investments, net of tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive income	$ 193	$ 477