Consolidated Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Statement [Abstract]
Net sales	$ 175,510	$ 170,812	$ 193,533	$ 194,322	$ 209,417	$ 220,881	$ 200,989	$ 176,049	$ 734,177	$ 807,336	$ 743,130
Cost of sales									579,109	564,089	543,596
Gross profit	17,179	34,413	45,241	58,235	63,186	74,649	59,900	45,512	155,068	243,247	199,534
Selling, general and administrative expenses									85,767	82,677	70,223
Research and development expenses									87,862	76,255	76,589
Restructuring and impairment charges									8,207		3,599
Special expense for IPO incentive											12,146
Operating income (loss)	(33,179)	(10,220)	2,665	13,966	21,913	32,492	20,345	9,565	(26,768)	84,315	36,977
Other income (expenses)
Interest expense, net									(20,360)	(22,600)	(24,984)
Foreign currency gain (loss), net									16,837	57,280	(11,348)
Loss on early extinguishment of senior notes									(32,812)		(5,459)
Others									2,870	3,890	1,628
Net other income (expenses)									(33,465)	38,570	(40,163)
Income (loss) before income taxes									(60,233)	122,885	(3,186)
Income tax expenses									3,970	12,847	8,115
Net income (loss)	$ (22,197)	$ 251	$ (24,668)	$ (17,589)	$ 47,009	$ 47,210	$ 2,458	$ 13,361	$ (64,203)	$ 110,038	$ (11,301)
Earnings (loss) per common share-
Basic	$ (0.64)	$ 0.01	$ (0.70)	$ (0.49)	$ 1.31	$ 1.30	$ 0.07	$ 0.36	$ (1.82)	$ 3.01	$ (0.29)
Diluted	$ (0.64)	$ 0.01	$ (0.70)	$ (0.49)	$ 1.27	$ 1.27	$ 0.07	$ 0.35	$ (1.82)	$ 2.93	$ (0.29)
Weighted average number of shares-
Basic	34,480,849	35,443,820	35,474,001	35,539,413	35,845,367	36,199,655	36,713,569	37,524,127	35,232,194	36,567,684	38,775,642
Diluted	34,480,849	37,484,601	35,474,001	35,539,413	37,050,284	37,290,612	37,517,712	38,282,932	35,232,194	37,533,391	38,775,642