Segment Reporting and Geographic Information - (Tables)

3 Months Ended

Mar. 31, 2019

Segment Reporting And Geographic Information [Abstract]

Schedule of Revenue from External Customers by Products and Services

The following table lists the different sources of revenue:

	Three Months Ended
	March 31,
	2019				2018
Systems and Software:
Process control	$	39,158	64	%	$	48,033	66	%
Lithography		3,614	6	%		8,069	11	%
Software licensing, support and maintenance		7,037	12	%		7,455	10	%
Parts		8,077	13	%		6,985	10	%
Services		3,006	5	%		2,554	3	%
Total revenue	$	60,892	100	%	$	73,096	100	%

Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area

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

	Three Months Ended
	March 31,
	2019		2018
Revenue from third parties:
United States	$	9,131	$	9,068
Taiwan		11,031		14,467
Japan		3,940		4,130
China		16,044		17,971
South Korea		10,771		17,230
Singapore		2,016		4,282
Other Asia		993		1,917
Germany		1,850		1,324
Other Europe		5,116		2,707
Total revenue	$	60,892	$	73,096

Schedule of Revenue by Major Customers by Reporting Segments

The following customers accounted for more than 10% of total revenue for the indicated periods:

	Three Months Ended March 31,
	2019			2018
Customer A		27.2	%		14.2	%
Customer B		—	%		11.2	%