Segment Reporting and Geographic Information Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Revenues	$ 61,641	$ 58,597	$ 178,704	$ 170,633
UNITED STATES
Segment Reporting Information [Line Items]
Revenues	10,750	9,455	23,784	38,876
TAIWAN, PROVINCE OF CHINA
Segment Reporting Information [Line Items]
Revenues	18,535	9,035	55,105	38,623
JAPAN
Segment Reporting Information [Line Items]
Revenues	2,970	2,881	9,071	8,113
CHINA
Segment Reporting Information [Line Items]
Revenues	5,942	6,529	25,591	13,474
South Korea [Domain]
Segment Reporting Information [Line Items]
Revenues	6,342	2,945	10,191	13,184
SINGAPORE
Segment Reporting Information [Line Items]
Revenues	7,415	10,568	29,341	20,847
Asia [Member]
Segment Reporting Information [Line Items]
Revenues	1,079	1,571	3,625	2,428
GERMANY
Segment Reporting Information [Line Items]
Revenues	1,400	8,716	6,331	24,741
Other Europe [Domain]
Segment Reporting Information [Line Items]
Revenues	7,208	6,897	15,665	10,347
Sales [Member]
Segment Reporting Information [Line Items]
Revenues	$ 61,641	$ 58,597	$ 178,704	$ 170,633