Summary of Long-lived Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Long-Lived Assets by Geographical Areas [Line Items]
Property, plant and equipment, net	$ 61,718	$ 35,421	$ 40,550
UNITED STATES
Long-Lived Assets by Geographical Areas [Line Items]
Property, plant and equipment, net	29,920	29,509	34,907
Europe
Long-Lived Assets by Geographical Areas [Line Items]
Property, plant and equipment, net	30,621	4,588	4,014
CHINA
Long-Lived Assets by Geographical Areas [Line Items]
Property, plant and equipment, net	1,127	1,286	1,593
Asia Pacific And Other Non Us Countries
Long-Lived Assets by Geographical Areas [Line Items]
Property, plant and equipment, net	$ 50	$ 38	$ 36