Summary of Significant Accounting Policies - Weighted Average Number of Shares Outstanding Used to Compute Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jul. 02, 2016	Jul. 01, 2017	Jul. 02, 2016
Accounting Policies [Abstract]
Net income	$ 3,823	$ 3,861	$ 5,938	$ 17,411
Weighted-average number of common shares outstanding
Basic weighted-average common shares outstanding (in shares)	11,237	11,155	11,253	11,127
Dilutive potential common shares (in shares)	254	109	303	118
Diluted weighted-average common shares outstanding (in shares)	11,491	11,264	11,556	11,245
Earnings per share
Basic (in dollars per share)	$ 0.34	$ 0.35	$ 0.53	$ 1.56
Diluted (in dollars per share)	$ 0.33	$ 0.34	$ 0.51	$ 1.55