Investments - Non-Marketable Equity Securities (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 27, 2020	Mar. 29, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019	Dec. 29, 2019
Net Investment Income [Line Items]
Equity securities	$ 21,800			$ 21,800		$ 13,400
Interest income and other expense, net	$ 3,720		$ 5,078	$ 20,724	$ 17,093
Realized gain on partial sale of investment		$ 2,500
Unrealized gain due to mark to market of remaining investment		7,600
Non-marketable equity securities
Net Investment Income [Line Items]
Interest income and other expense, net		$ 10,100