Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Income Tax Expense (Benefit)	$ 1,363	$ 242	$ 2,388	$ (1)
Unrecognized tax benefits	5,400		5,400		$ 5,300
Expected reduction in unrecognized tax benefits	$ 3,500		$ 3,500
Maximum
Operating Loss Carryforwards [Line Items]
Income Tax Expense (Benefit)				$ 100