Valuation and Qualifying Accounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 1,937	$ 545	$ 292
Charged to Costs ans Expenses	529	1,314	287
Charged to Other Accounts	4	5
Deductions from Reserves	4	(73)	(34)
Balance at End of Period	2,474	1,937	545
Valuation Allowance of Deferred Tax Assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	3,702	6,579	8,224
Charged to Costs ans Expenses			(1,645)
Charged to Other Accounts	(1,503)	(2,877)
Balance at End of Period	2,199	3,702	6,579
Inventory Valuation Reserve [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	1,127	572	632
Charged to Costs ans Expenses	1,307	532	20
Charged to Other Accounts	(34)	33
Deductions from Reserves	(215)	(10)	(80)
Balance at End of Period	$ 2,185	$ 1,127	$ 572