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
	Mar. 31, 2018	Apr. 01, 2017
Accounting Policies [Abstract]
Net income	$ 2,600	$ 2,115
Weighted-average number of common shares outstanding
Basic weighted-average common shares outstanding (in shares)	11,346	11,208
Dilutive potential common shares (in shares)	267	287
Diluted weighted-average common shares outstanding (in shares)	11,613	11,495
Earnings per share
Basic (in dollars per share)	$ 0.23	$ 0.19
Diluted (in dollars per share)	$ 0.22	$ 0.18