Debt Obligations - Interest Expense, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2019	Sep. 30, 2018	Sep. 29, 2019	Sep. 30, 2018
Debt Instrument [Line Items]
Interest expense	$ 7,118	$ 7,061	$ 21,314	$ 21,078
Amortization of debt costs and (premium)/discount on debt	(1,278)	839	(590)	2,528
Capitalized interest	(7)	(38)	(59)	(412)
Interest income and other expense, net	(5,078)	(3,836)	(17,093)	(9,755)
Total interest expense and other, net	$ 755	$ 4,026	3,572	$ 13,439
Non-marketable equity securities
Debt Instrument [Line Items]
Interest income and other expense, net			$ (1,900)