Inventories (Details) - USD ($) $ in Thousands	Jul. 03, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Raw materials	$ 38,418	$ 38,934
Work-in-process	10,621	9,899
Finished goods	9,727	11,945
Demo and consigned inventory	1,644	2,165
Total inventories	$ 60,410	$ 62,943