Effect of Recording Equity-Based Compensation (Detail) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation	$ 1,077	$ 1,111
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation	255	276
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation	718	634
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation	$ 104	$ 201