Contingency (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Mar. 28, 2018
Commitments and Contingencies Disclosure [Abstract]
Sales tax examination excluding penalties and interest accrued		$ 824
Sales tax examination penalties and interest accrued		339
Sales tax examination liability refund adjustment from settlement with tax authority		$ 1,163
Sales tax contingent liabilities	$ 96