Segment Reporting (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Segment Reporting Information [Line Items]
Revenues	$ 41,650,000	$ 45,709,000
Inspection Revenue [Member]
Segment Reporting Information [Line Items]
Revenues	24,879,000	22,856,000
Percentage of Inspection Revenues [Member]
Segment Reporting Information [Line Items]
Revenues	0.60	0.50
Metrology Revenue [Member]
Segment Reporting Information [Line Items]
Revenues	288,000	10,237,000
Percentage of Metrology Revenue [Member]
Segment Reporting Information [Line Items]
Revenues	0.01	0.22
Lithography Revenue [Domain]
Segment Reporting Information [Line Items]
Revenues	3,700,000	0
Percentage of Lithography Revenue [Member] [Domain]
Segment Reporting Information [Line Items]
Revenues	0.09	0.00
Data Analysis & Review [Member]
Segment Reporting Information [Line Items]
Revenues	4,157,000	4,547,000
Percentage of Data Analysis & Review [Member]
Segment Reporting Information [Line Items]
Revenues	0.10	0.10
Sales Revenue, Goods, Net [Member]
Segment Reporting Information [Line Items]
Revenues	5,546,000	5,504,000
Percentage of Parts [Member]
Segment Reporting Information [Line Items]
Revenues	0.13	0.12
Sales Revenue, Services, Net [Member]
Segment Reporting Information [Line Items]
Revenues	3,080,000	2,565,000
Percentage of Service [Member]
Segment Reporting Information [Line Items]
Revenues	0.07	0.06
Sales [Member]
Segment Reporting Information [Line Items]
Revenues	41,650,000	45,709,000
Percentage of Total Revenue [Member]
Segment Reporting Information [Line Items]
Revenues	$ 1.00	$ 1.00