Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Net sales	$ 167,106	$ 162,015	$ 315,211	$ 326,900
Cost of sales	130,357	126,729	244,213	256,637
Gross profit	36,749	35,286	70,998	70,263
Operating expenses
Selling, general and administrative expenses	25,948	28,588	45,900	53,618
Research and development expenses	18,178	21,931	35,993	44,091
Restructuring gain			(7,785)
Total operating expenses	44,126	50,519	74,108	97,709
Operating loss	(7,377)	(15,233)	(3,110)	(27,446)
Interest expense	(4,073)	(3,987)	(8,130)	(8,112)
Foreign currency gain (loss), net	(7,101)	(12,296)	1,094	(15,472)
Other income, net	1,007	288	1,542	906
Loss before income taxes	(17,544)	(31,228)	(8,604)	(50,124)
Income tax expenses (benefits)	272	(602)	1,087	531
Net loss	$ (17,816)	$ (30,626)	$ (9,691)	$ (50,655)
Loss per common share-
Basic	$ (0.51)	$ (0.90)	$ (0.28)	$ (1.49)
Diluted	$ (0.51)	$ (0.90)	$ (0.28)	$ (1.49)
Weighted average number of shares-
Basic	34,716,081	34,092,402	34,707,492	34,074,534
Diluted	34,716,081	34,092,402	34,707,492	34,074,534