CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Net sales	$ 848,904	$ 890,651	$ 826,846
Cost of goods sold	600,321	613,372	589,010
Gross profit	248,583	277,279	237,836
Operating expenses
Selling, general and administrative	139,245	133,701	132,106
Research and development	57,027	52,136	48,302
Amortization of acquisition related intangible assets	8,596	7,914	8,078
Impairment of goodwill			5,318
Restructuring			1,535
Loss (gain) on sale of assets	1,613	(983)	216
Total operating expenses	206,481	192,768	195,555
Income from operations	42,102	84,511	42,281
Other income/(expense)
Interest income	1,006	1,470	1,274
Interest expense	(4,232)	(4,332)	(5,580)
Gain on securities carried at fair value	400	1,364	601
Other	1,319	2,979	9
Total other income (expenses)	(1,507)	1,481	(3,696)
Income before income taxes and noncontrolling interest	40,595	85,992	38,585
Income tax provision	14,082	20,359	14,481
Net income	26,513	65,633	24,104
Less net (income) loss attributable to noncontrolling interest	(2,239)	(1,955)	2,428
Net income attributable to common stockholders	$ 24,274	$ 63,678	$ 26,532
Earnings per share attributable to common stockholders
Basic	$ 0.50	$ 1.35	$ 0.57
Diluted	$ 0.49	$ 1.31	$ 0.56
Number of shares used in computation
Basic	48,210	47,184	46,363
Diluted	49,500	48,594	47,658