Quantitative Range of Significant Unobservable Inputs Used in Calculation of Fair Value of Continent Consideration Liability (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 29, 2018	Dec. 30, 2017
Business Acquisition, Contingent Consideration [Line Items]
Fair Value	$ 370	$ 362
Fair Value, Inputs, Level 3 | Revenue Earnout
Business Acquisition, Contingent Consideration [Line Items]
Valuation technique	Discounted cash flow
Fair Value	$ 370
Fair Value, Inputs, Level 3 | Revenue Earnout | Weighted Average | Measurement Input, Discount Rate
Business Acquisition, Contingent Consideration [Line Items]
Weighted average cost of capital	12.10%