Inventories, net (Tables)

12 Months Ended

Dec. 31, 2018

Inventories, net

Schedule of components of inventories

	December 31,
	2018		2017
	(in thousands)
Raw materials	$	91,875	$	82,313
Work in process		23,857		31,651
Finished goods (completed systems)		13,268		6,580
Inventories, net	$	129,000	$	120,544