Business Segment and Foreign Operations - Long-lived Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Long-lived Assets from External Customers and Long-Lived Assets [Line Items]
Long-lived tangible assets	$ 89,744	$ 81,606
United States [Member]
Long-lived Assets from External Customers and Long-Lived Assets [Line Items]
Long-lived tangible assets	5,486	5,716
People's Republic of China [Member]
Long-lived Assets from External Customers and Long-Lived Assets [Line Items]
Long-lived tangible assets	78,654	70,619
All Other Countries [Member]
Long-lived Assets from External Customers and Long-Lived Assets [Line Items]
Long-lived tangible assets	$ 5,604	$ 5,271