Inventories, net (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Inventories, net
Raw materials	$ 74,245	$ 65,723
Work in process	33,277	22,358
Finished goods (completed systems)	14,479	15,982
Inventories, net	122,001	104,063
Inventory reserves	$ 17,600	$ 23,600