Fair Value Measurements and Disclosures - Measured at Fair Value on Recurring Basis (Parenthetical) (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Mar. 30, 2019	Dec. 29, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	$ 15,515	$ 2,106
Cash [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash equivalents	$ 79,700	$ 108,800