Net Sales to External Customers Based upon Geographic Location (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 31, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Geographic Reporting Disclosure [Line Items]
Net sales to external customers	$ 104,153	$ 82,239	$ 82,060	$ 73,374	$ 89,895	$ 68,190	$ 68,329	$ 65,370	$ 341,826	$ 291,784	$ 273,395
UNITED STATES
Geographic Reporting Disclosure [Line Items]
Net sales to external customers									124,851	109,757	97,912
Americas-Other
Geographic Reporting Disclosure [Line Items]
Net sales to external customers									14,117	10,678	10,704
Germany
Geographic Reporting Disclosure [Line Items]
Net sales to external customers									50,437	42,471	42,413
Europe-Other
Geographic Reporting Disclosure [Line Items]
Net sales to external customers									69,742	60,944	57,698
JAPAN
Geographic Reporting Disclosure [Line Items]
Net sales to external customers									32,531	23,795	25,553
Asia And Other
Geographic Reporting Disclosure [Line Items]
Net sales to external customers									$ 50,148	$ 44,139	$ 39,115