Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Statement [Abstract]
Net sales	$ 162,015	$ 172,070	$ 326,900	$ 336,234
Cost of sales	126,729	136,613	256,637	260,500
Gross profit	35,286	35,457	70,263	75,734
Operating expenses
Selling, general and administrative expenses	28,588	30,746	53,618	55,773
Research and development expenses	21,931	24,059	44,091	47,196
Total operating expenses	50,519	54,805	97,709	102,969
Operating loss	(15,233)	(19,348)	(27,446)	(27,235)
Interest expense, net	(3,933)	(4,007)	(7,996)	(8,077)
Foreign currency gain (loss), net	(12,296)	38,424	(15,472)	29,018
Other income, net	234	597	790	1,158
Income (loss) before income taxes	(31,228)	15,666	(50,124)	(5,136)
Income tax expenses (benefits)	(602)	656	531	1,459
Net income (loss)	$ (30,626)	$ 15,010	$ (50,655)	$ (6,595)
Earnings (loss) per common share-
Basic	$ (0.90)	$ 0.44	$ (1.49)	$ (0.19)
Diluted	$ (0.90)	$ 0.43	$ (1.49)	$ (0.19)
Weighted average number of shares-
Basic	34,092,402	34,056,359	34,074,534	34,054,626
Diluted	34,092,402	35,177,915	34,074,534	34,054,626