Segment Reporting and Geographic Information - (Tables)

9 Months Ended

Sep. 30, 2014

Segment Reporting and Geographic Information [Abstract]

Schedule of revenue from external customers by Products and Services [Table Text Block]

The following table lists the different sources of revenue:

	Three Months Ended								Nine Months Ended
	September 30,								September 30,
	2014				2013				2014				2013
Systems and Software:
Inspection	$	23,134	49	%	$	21,734	49	%	$	63,987	49	%	$	73,441	55	%
Metrology	2,692		6	%	5,470		12	%	13,093		10	%	11,627		9	%
Lithography	7,304		16	%	3,618		8	%	10,961		8	%	7,318		6	%
Data Analysis and Review	5,463		12	%	4,724		11	%	18,393		14	%	13,737		10	%
Parts	4,939		10	%	5,235		12	%	15,051		11	%	16,036		13	%
Services	3,428		7	%	3,263		8	%	10,142		8	%	9,594		7	%
Total revenue	$	46,960	100	%	$	44,044	100	%	$	131,627	100	%	$	131,753	100	%

Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Table Text Block]

For geographical revenue reporting, revenues are attributed to the geographic location in which the product is shipped.  Revenue by geographic region is as follows:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2014		2013		2014		2013
United States	$	19,683	$	13,484	$	39,320	$	32,962
Taiwan	14,592		11,136		34,774		43,757
Japan	1,236		2,345		7,589		6,052
China	1,807		4,015		8,932		11,284
South Korea	1,434		1,928		9,873		6,995
Other Asia	1,942		5,552		14,528		14,127
Germany	3,166		1,771		8,418		4,242
Other Europe	3,100		3,813		8,193		12,334
Total revenue	$	46,960	$	44,044	$	131,627	$	131,753

Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block]

The following customers each accounted for more than 10% of total revenues for the indicated periods.

	Nine Months Ended
	September 30,
	2014		2013
Customer A	7.4	%	13.0	%
Customer B	4.2	%	11.2	%