CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Net sales	$ 942,162	$ 848,904	$ 890,651
Cost of goods sold	655,239	600,321	613,372
Gross profit	286,923	248,583	277,279
Operating expenses
Selling, general and administrative	158,256	139,245	133,701
Research and development	69,937	57,027	52,136
Amortization of acquisition related intangible assets	20,478	8,596	7,914
Other operating expenses	196	1,613	(983)
Total operating expenses	248,867	206,481	192,768
Income from operations	38,056	42,102	84,511
Other (expense)/income
Interest income	1,357	1,006	1,470
Interest expense	(13,257)	(4,232)	(4,332)
Gain on securities carried at fair value		400	1,364
Impairment of cost-basis investment	(3,218)
Other	2,097	1,319	2,979
Total other (expense) income	(13,021)	(1,507)	1,481
Income before income taxes and noncontrolling interest	25,035	40,595	85,992
Income tax provision	6,558	14,082	20,359
Net income	18,477	26,513	65,633
Less: net (income) loss attributable to noncontrolling interest	(2,542)	(2,239)	(1,955)
Net income attributable to common stockholders	$ 15,935	$ 24,274	$ 63,678
Earnings per share attributable to common stockholders
Basic	$ 0.33	$ 0.50	$ 1.35
Diluted	$ 0.32	$ 0.49	$ 1.31
Number of shares used in computation
Basic	48,597	48,210	47,184
Diluted	49,789	49,500	48,594