Business Segment and Foreign Operations - Long-lived Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Long-lived Assets from External Customers and Long-Lived Assets [Line Items]
Total long-lived tangible assets	$ 117,273	$ 110,247
United States
Long-lived Assets from External Customers and Long-Lived Assets [Line Items]
Total long-lived tangible assets	13,004	11,948
People's Republic of China (PRC)
Long-lived Assets from External Customers and Long-Lived Assets [Line Items]
Total long-lived tangible assets	100,300	94,113
All other countries
Long-lived Assets from External Customers and Long-Lived Assets [Line Items]
Total long-lived tangible assets	$ 3,969	$ 4,186