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. 30, 2019	Mar. 31, 2018
Accounting Policies [Abstract]
Net income	$ 7,472	$ 2,600
Weighted-average number of common shares outstanding
Basic weighted-average common shares outstanding (in shares)	11,434	11,346
Dilutive potential common shares (in shares)	321	267
Diluted weighted-average common shares outstanding (in shares)	11,755	11,613
Earnings per share
Basic (in dollars per share)	$ 0.65	$ 0.23
Diluted (in dollars per share)	$ 0.64	$ 0.22