CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Statement Abstract
NET SALES	$ 633,806	$ 635,251	$ 612,886
COST OF GOODS SOLD	472,220	441,554	388,017
Gross profit	161,586	193,697	224,869
OPERATING EXPENSES
Selling, general and administrative	101,363	89,974	88,784
Research and development	33,761	27,231	26,584
Amortization of acquisition related intangible assets	5,122	4,503	6,406
Gain on sale of assets	(3,556)	0	(1,837)
Total operating expenses	136,690	121,708	119,937
Income from operations	24,896	71,989	104,932
OTHER INCOME (EXPENSES)
Interest income	778	1,024	2,842
Interest expense	(876)	(3,139)	(5,229)
Amortization of debt discount	0	(6,032)	(7,656)
Gain (loss) on securities carried at fair value	7,100	(1,039)	0
Other	(1,091)	861	3,214
Total other income (expenses)	5,911	(8,325)	(6,829)
Income before income taxes and noncontrolling interest	30,807	63,664	98,103
INCOME TAX PROVISION	4,825	10,157	17,839
NET INCOME	25,982	53,507	80,264
Less: NET INCOME attributable to noncontrolling interest	(1,830)	(2,770)	(3,531)
NET INCOME attributable to common stockholders	$ 24,152	$ 50,737	$ 76,733
EARNINGS PER SHARE attributable to common stockholders
Basic	$ 0.53	$ 1.12	$ 1.74
Diluted	$ 0.51	$ 1.09	$ 1.68
Number of shares used in computation
Basic	45,780	45,202	44,146
Diluted	46,899	46,713	45,546