Effect of Recording Equity-Based Compensation (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Equity Based Compensation Related to Employee Stock Purchase Programs [Line Items]
Total equity-based compensation	$ 856,000	$ 754,000	$ 2,219,000	$ 1,836,000
Tax benefit recognized	3,000	8,000	9,000	18,000
Stock Options
Equity Based Compensation Related to Employee Stock Purchase Programs [Line Items]
Total equity-based compensation	371,000	375,000	765,000	651,000
Restricted Stock Units (RSUs)
Equity Based Compensation Related to Employee Stock Purchase Programs [Line Items]
Total equity-based compensation	402,000	130,000	1,070,000	314,000
ESPP awards
Equity Based Compensation Related to Employee Stock Purchase Programs [Line Items]
Total equity-based compensation	$ 83,000	$ 249,000	$ 384,000	$ 871,000