CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Net sales	$ 208,888	$ 233,777	$ 634,522	$ 666,980
Cost of goods sold	147,252	159,045	439,536	460,363
Gross profit	61,636	74,732	194,986	206,617
Operating expenses
Selling, general and administrative	34,669	33,897	98,282	99,518
Research and development	13,745	13,864	40,644	39,565
Amortization of acquisition related intangible assets	1,828	1,987	5,630	5,960
Loss (gain) on fixed assets	1,421	(20)	1,556	(916)
Total operating expenses	51,663	49,728	146,112	144,127
Income from operations	9,973	25,004	48,874	62,490
Other income (expense)	255	1,300	(1,426)	309
Income before income taxes and noncontrolling interest	10,228	26,304	47,448	62,799
Income tax provision	6,593	6,172	16,179	14,370
Net income	3,635	20,132	31,269	48,429
Less net income attributable to noncontrolling interest	798	705	2,222	1,415
Net income attributable to common stockholders	$ 2,837	$ 19,427	$ 29,047	$ 47,014
Earnings per share attributable to common stockholders:
Basic	$ 0.06	$ 0.41	$ 0.60	$ 1.00
Diluted	$ 0.06	$ 0.40	$ 0.59	$ 0.97
Number of shares used in earnings per share computation:
Basic	48,586	47,548	48,114	47,047
Diluted	49,564	48,736	49,351	48,385