Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Allowance for Doubtful Accounts Receivable [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	$ 126	$ 73	$ 150
Additions to Allowance	129	78
Charges Utilized/Write-offs	(85)	(25)	(77)
Balance at end of period	170	126	73
Valuation Allowance for Deferred Tax Assets [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	13,702	10,980	36,786
Additions to Allowance	470	2,984	1,643
Charges Utilized/Write-offs	(3,206)	(262)	(27,449)
Balance at end of period	$ 10,966	$ 13,702	$ 10,980