Accrued Expenses - Changes in Warranty Obligations (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Product Warranty Accrual [Line Items]
Beginning Balance	$ 2,097	$ 1,985
Provisions for warranties issued during the period	1,725	1,835
Fulfillment of warranty obligations	(1,609)	(1,664)
Foreign exchange rate changes	43	(59)
Ending Balance	$ 2,256	$ 2,097