Property, Plant and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Property, plant and equipment [Abstract]
Property, plant and equipment, net	$ 58,763	$ 46,530
Machinery and equipment
Property, plant and equipment [Abstract]
Property, plant and equipment, gross	45,954	44,549
Less: accumulated depreciation and amortization	(42,217)	(40,845)
Building
Property, plant and equipment [Abstract]
Property, plant and equipment, gross	33,635	32,461
Less: accumulated depreciation and amortization	(12,234)	(11,501)
Leasehold improvements
Property, plant and equipment [Abstract]
Property, plant and equipment, gross	5,715	5,539
Less: accumulated depreciation and amortization	(4,538)	(4,288)
Construction in progress
Property, plant and equipment [Abstract]
Property, plant and equipment, gross	32,448	20,615
Construction in progress Dingxin location
Property, plant and equipment [Abstract]
Property, plant and equipment, gross		14,800
Construction in progress Dingxin and Chaoyang locations
Property, plant and equipment [Abstract]
Property, plant and equipment, gross	22,800
Construction in progress manufacturing equipment purchases
Property, plant and equipment [Abstract]
Property, plant and equipment, gross	5,600	3,600
Construction in progress other consolidated subsidiaries
Property, plant and equipment [Abstract]
Property, plant and equipment, gross	$ 4,000	$ 2,200