Debt Obligations - Interest Expense, Net (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Debt Instrument [Line Items]
Interest expense	$ 7,137		$ 7,059	$ 14,196	$ 14,017
Amortization of debt costs and (premium)/discount on debt	(205)		813	688	1,689
Capitalized interest	(8)		(219)	(52)	(374)
Interest income and other expense, net	(5,410)		(3,117)	(12,015)	(5,919)
Total interest expense and other, net	$ 1,514		$ 4,536	$ 2,817	$ 9,413
Non-marketable equity securities
Debt Instrument [Line Items]
Interest income and other expense, net		$ (1,900)