Organization And Summary Of Significant Accounting Policies - Liquidity (Details) - USD ($)	Sep. 27, 2020	Dec. 29, 2019	Dec. 28, 2014	Jun. 30, 2014
Debt Instrument [Line Items]
Debt face amount	$ 894,773,000	$ 986,244,000
Convertible Debt
Debt Instrument [Line Items]
Debt face amount	$ 726,583,000	825,000,000
0.875% debentures due 2021
Debt Instrument [Line Items]
Interest rate	0.875%			0.875%
Debt face amount				$ 400,000,000.0
0.875% debentures due 2021 | Convertible Debt
Debt Instrument [Line Items]
Interest rate	0.875%		0.875%
Debt face amount	$ 301,583,000	$ 400,000,000