Segment Reporting and Geographic Information - (Tables)

3 Months Ended

Mar. 31, 2017

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,
	2017				2016
Systems and software:
Process Control	$	43,876	72	%	$	36,459	67	%
Lithography	17		—	%	170		—	%
Software	7,498		13	%	7,422		14	%
Parts	6,330		10	%	7,160		13	%
Services	2,958		5	%	3,151		6	%
Total revenue	$	60,679	100	%	$	54,362	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,
	2017		2016
United States	$	9,009	$	7,388
Taiwan	13,833		22,035
Japan	3,208		2,937
China	14,101		8,825
South Korea	9,530		1,623
Singapore	3,266		7,047
Other Asia	114		871
Germany	3,080		697
Other Europe	4,538		2,939
Total revenue	$	60,679	$	54,362

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,
	2017		2016
Customer A	17.2	%	0.6	%
Customer B	5.6	%	26.9	%