Segment Reporting and Geographic Information Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Revenues	$ 46,960	$ 44,044	$ 131,627	$ 131,753
UNITED STATES
Segment Reporting Information [Line Items]
Revenues	19,683	13,484	39,320	32,962
TAIWAN, PROVINCE OF CHINA
Segment Reporting Information [Line Items]
Revenues	14,592	11,136	34,774	43,757
JAPAN
Segment Reporting Information [Line Items]
Revenues	1,236	2,345	7,589	6,052
CHINA
Segment Reporting Information [Line Items]
Revenues	1,807	4,015	8,932	11,284
South Korea [Domain]
Segment Reporting Information [Line Items]
Revenues	1,434	1,928	9,873	6,995
Asia [Member]
Segment Reporting Information [Line Items]
Revenues	1,942	5,552	14,528	14,127
GERMANY
Segment Reporting Information [Line Items]
Revenues	3,166	1,771	8,418	4,242
Other Europe [Domain]
Segment Reporting Information [Line Items]
Revenues	3,100	3,813	8,193	12,334
Sales [Member]
Segment Reporting Information [Line Items]
Revenues	$ 46,960	$ 44,044	$ 131,627	$ 131,753