Consolidated Statements of Operations - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Income Statement [Abstract]      
Net sales $ 687,969 $ 633,712 $ 698,218
Cost of sales 531,743 498,848 545,356
Gross profit 156,226 134,864 152,862
Operating expenses      
Selling, general and administrative expenses 89,094 94,378 126,954
Research and development expenses 72,180 83,420 92,765
Restructuring and impairment charges (gain) (7,785)   10,269
Total operating expenses 153,489 177,798 229,988
Operating income (loss) 2,737 (42,934) (77,126)
Interest expense (16,238) (16,268) (16,833)
Foreign currency loss, net (15,360) (42,531) (24,650)
Other income, net 2,990 1,779 2,900
Loss before income tax expenses (25,871) (99,954) (115,709)
Income tax expenses (benefits) 3,744 (15,087) 1,523
Net loss $ (29,615) $ (84,867) $ (117,232)
Loss per common share-      
Basic/ Diluted $ (0.85) $ (2.47) $ (3.44)
Weighted average number of shares-      
Basic/ Diluted 34,833,967 34,380,517 34,055,513