Amortization Expense of Company's Purchased Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Finite Lived Intangible Assets [Line Items]
Cost of goods sold	$ 428		$ 598
Operating expenses	321	[1]	354
Total	$ 749		$ 952

[1] Restated and Revised, see Note 2