Business Segment and Geographic Region Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014 item	Dec. 31, 2013	Dec. 31, 2012
Business Segment and Geographic Region Information
Number of business segments									1
Revenue by product lines
Revenue	$ 62,530	$ 38,531	$ 41,150	$ 60,840	$ 58,574	$ 48,831	$ 47,501	$ 40,726	$ 203,051	$ 195,632	$ 203,385
Ion implantation systems, services, and royalties
Revenue by product lines
Revenue									183,148	164,030	156,090
Other systems and services
Revenue by product lines
Revenue									$ 19,903	$ 31,602	$ 47,295