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
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Accounting Policies [Abstract]
Net income	$ 7,815	$ 1,591	$ 15,287	$ 4,191
Weighted-average number of common shares outstanding
Basic weighted-average common shares outstanding (in shares)	11,513	11,394	11,475	11,370
Dilutive potential common shares (in shares)	245	230	279	239
Diluted weighted-average common shares outstanding (in shares)	11,758	11,624	11,754	11,609
Earnings per share
Basic (in dollars per share)	$ 0.68	$ 0.14	$ 1.33	$ 0.37
Diluted (in dollars per share)	$ 0.66	$ 0.14	$ 1.30	$ 0.36