Inventories, net (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Inventories, net
Raw materials	$ 64,277,000		$ 64,277,000		$ 56,942,000
Work in process	27,963,000		27,963,000		27,462,000
Finished goods (completed systems)	15,576,000		15,576,000		11,385,000
Inventories, net	107,816,000		107,816,000		95,789,000
Inventory reserves	23,900,000		23,900,000		25,100,000
Inventories, net
Charge to cost of sales relating to inventory			590,000	2,451,000
Cost of sales due to below normal production capacity	600,000	100,000	1,000,000	600,000
Dry strip product line, intellectual property rights and certain assets
Inventories, net
Charge to cost of sales relating to inventory		$ 0		$ 2,100,000
Size of dry strip wafer equipment and products, Company license to make and sell (in millimeters)				300