Amortization Expense of Company's Purchased Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Finite Lived Intangible Assets [Line Items]
Cost of goods sold	$ 738	$ 616	$ 1,937	$ 1,830
Operating expenses	381	321	1,128	996
Total	$ 1,119	$ 937	$ 3,065	$ 2,826