Segment Reporting and Geographic Information - (Tables)

3 Months Ended

Mar. 31, 2018

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,
	2018				2017
Systems and Software:
Process control	$	48,033	66	%	$	43,876	72	%
Lithography		8,069	11	%		17	—	%
Software licensing, support and maintenance		7,455	10	%		7,498	13	%
Parts		6,985	10	%		6,330	10	%
Services		2,554	3	%		2,958	5	%
Total revenue	$	73,096	100	%	$	60,679	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 in which the product is shipped.  Revenue by geographic region is as follows:

	Three Months Ended
	March 31,
	2018		2017
Revenue from third parties:
United States	$	9,068	$	9,009
Taiwan		14,467		13,833
Japan		4,130		3,208
China		17,971		14,101
South Korea		17,230		9,530
Singapore		4,282		3,266
Other Asia		1,917		114
Germany		1,324		3,080
Other Europe		2,707		4,538
Total revenue	$	73,096	$	60,679

Schedule of Revenue by Major Customers by Reporting Segments

The following customer accounted for more than 10% of total revenue for the indicated periods.

	Three Months Ended March 31,
	2018			2017
Customer A		14.2	%		17.2	%
Customer B		11.2	%		—	%