Activity in Deferred Tax Valuation Allowance (Detail) - Valuation Allowance of Deferred Tax Assets - USD ($) $ in Thousands	12 Months Ended
	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Valuation Allowance [Line Items]
Beginning Balance	$ 111	$ 18	$ 18
Deductions	0	0	0
Charged to Expense	253	93	0
Ending Balance	$ 364	$ 111	$ 18