Discontinued Operations - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended			1 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Oct. 31, 2012 Laser Products	Dec. 31, 2012 Semiconductor Systems
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of Business Laser Systems	$ 7,000			$ 7,000
Gain on sale of business	2,255			2,255
Inventory provision	$ 4,472	$ 6,646	$ 6,361		$ 1,900