Business Segment and Geographic Region Information - Revenue by Product Line (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) item	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Business Segment and Geographic Region Information
Number of business segments | item									1
Revenue by product lines
Revenue	$ 70,458	$ 79,317	$ 78,437	$ 73,283	$ 62,530	$ 38,531	$ 41,150	$ 60,840	$ 301,495	$ 203,051	$ 195,632
Ion implantation systems, services, and royalties
Revenue by product lines
Revenue									282,624	183,148	164,030
Other systems and services
Revenue by product lines
Revenue									$ 18,871	$ 19,903	$ 31,602