Debt Obligations - Interest Expense, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Apr. 01, 2018
Debt Instrument [Line Items]
Interest expense	$ 7,059	$ 6,958
Amortization of debt costs and discount on debt	893	876
Capitalized interest	(44)	(155)
Interest income and other expense, net (1)	(6,605)	(2,802)
Total interest expense and other, net	1,303	$ 4,877
Non-marketable equity securities
Debt Instrument [Line Items]
Interest income and other expense, net (1)	$ (1,900)