Segment Reporting and Geographic Information - (Tables)

3 Months Ended

Mar. 31, 2016

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
	March 31,
	2016				2015
Systems and Software:
Process Control	$	36,459	67	%	$	36,061	69	%
Lithography	170		—	%	21		—	%
Software	7,422		14	%	7,794		15	%
Parts	7,160		13	%	5,655		10	%
Services	3,151		6	%	3,039		6	%
Total revenue	$	54,362	100	%	$	52,570	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
	March 31,
	2016		2015
United States	$	7,388	$	17,648
Taiwan	22,035		13,329
Japan	2,937		1,314
China	8,825		6,088
South Korea	1,623		3,531
Singapore	7,047		1,738
Other Asia	871		39
Germany	697		7,055
Other Europe	2,939		1,828
Total revenue	$	54,362	$	52,570

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.

	Three Months Ended
	March 31,
	2016		2015
Customer A	26.9	%	11.1	%
Customer B	4.3	%	10.2	%