Segment Reporting (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Rate	Sep. 30, 2012 Rate
Segment Reporting Information [Line Items]
Entity-Wide Revenue, Major Customer, Percentage			13.00%	6.40%
Revenues	$ 44,044,000	$ 62,152,000	$ 131,753,000	$ 164,187,000
Inspection Revenue [Member]
Segment Reporting Information [Line Items]
Revenues	21,734,000	42,415,000	73,441,000	99,220,000
Percentage of Inspection Revenues [Member]
Segment Reporting Information [Line Items]
Revenues	0.49	0.68	0.55	0.60
Metrology Revenue [Member]
Segment Reporting Information [Line Items]
Revenues	5,470,000	6,892,000	11,627,000	25,911,000
Percentage of Metrology Revenue [Member]
Segment Reporting Information [Line Items]
Revenues	0.12	0.11	0.09	0.16
Lithography Revenue [Domain]
Segment Reporting Information [Line Items]
Revenues	3,618,000	0	7,318,000	0
Percentage of Lithography Revenue [Member] [Domain]
Segment Reporting Information [Line Items]
Revenues	0.08	0.00	0.06	0.00
Data Analysis & Review [Member]
Segment Reporting Information [Line Items]
Revenues	4,724,000	5,082,000	13,737,000	15,213,000
Percentage of Data Analysis & Review [Member]
Segment Reporting Information [Line Items]
Revenues	0.11	0.08	0.10	0.09
Sales Revenue, Goods, Net [Member]
Segment Reporting Information [Line Items]
Revenues	5,235,000	4,838,000	16,036,000	15,488,000
Percentage of Parts [Member]
Segment Reporting Information [Line Items]
Revenues	0.12	0.08	0.13	0.10
Sales Revenue, Services, Net [Member]
Segment Reporting Information [Line Items]
Revenues	3,263,000	2,925,000	9,594,000	8,355,000
Percentage of Service [Member]
Segment Reporting Information [Line Items]
Revenues	0.08	0.05	0.07	0.05
Sales [Member]
Segment Reporting Information [Line Items]
Revenues	44,044,000	62,152,000	131,753,000	164,187,000
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			1.90%	12.10%
Major Customer Five [Domain]
Segment Reporting Information [Line Items]
Entity-Wide Revenue, Major Customer, Percentage			0.80%	11.80%