Segment Reporting (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013 Rate	Jun. 30, 2012 Rate	Jun. 30, 2013	Jun. 30, 2012
Segment Reporting Information [Line Items]
Entity-Wide Revenue, Major Customer, Percentage	11.00%	1.70%
Revenues	$ 46,059,000	$ 56,326,000	$ 87,709,000	$ 102,035,000
Inspection Revenue [Member]
Segment Reporting Information [Line Items]
Revenues	26,829,000	33,949,000	51,708,000	56,805,000
Percentage of Inspection Revenues [Member]
Segment Reporting Information [Line Items]
Revenues	0.58	0.60	0.59	0.56
Metrology Revenue [Member]
Segment Reporting Information [Line Items]
Revenues	5,869,000	8,782,000	6,157,000	19,019,000
Percentage of Metrology Revenue [Member]
Segment Reporting Information [Line Items]
Revenues	0.13	0.16	0.07	0.19
Lithography Revenue [Domain]
Segment Reporting Information [Line Items]
Revenues	0	0	3,700,000	0
Percentage of Lithography Revenue [Member] [Domain]
Segment Reporting Information [Line Items]
Revenues	0.00	0.00	0.04	0.00
Data Analysis & Review [Member]
Segment Reporting Information [Line Items]
Revenues	4,856,000	5,584,000	9,013,000	10,131,000
Percentage of Data Analysis & Review [Member]
Segment Reporting Information [Line Items]
Revenues	0.11	0.10	0.10	0.10
Sales Revenue, Goods, Net [Member]
Segment Reporting Information [Line Items]
Revenues	5,255,000	5,146,000	10,801,000	10,650,000
Percentage of Parts [Member]
Segment Reporting Information [Line Items]
Revenues	0.11	0.09	0.13	0.10
Sales Revenue, Services, Net [Member]
Segment Reporting Information [Line Items]
Revenues	3,250,000	2,865,000	6,330,000	5,430,000
Percentage of Service [Member]
Segment Reporting Information [Line Items]
Revenues	0.07	0.05	0.07	0.05
Sales [Member]
Segment Reporting Information [Line Items]
Revenues	46,059,000	56,326,000	87,709,000	102,035,000
Percentage of Total Revenue [Member]
Segment Reporting Information [Line Items]
Revenues	$ 1.00	$ 1.00	$ 1.00	$ 1.00
Major Customer Four [Domain]
Segment Reporting Information [Line Items]
Entity-Wide Revenue, Major Customer, Percentage	2.10%	18.40%
Major Customer Five [Domain]
Segment Reporting Information [Line Items]
Entity-Wide Revenue, Major Customer, Percentage	1.10%	12.50%