Effect of Recording Equity-Based Compensation (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation	$ 787	$ 880	$ 1,864	$ 1,991
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation	202	209	458	485
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation	495	480	1,212	1,114
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation	$ 90	$ 191	$ 194	$ 392