CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Net sales	$ 280,717	$ 302,293
Cost of goods sold	184,875	189,882
Gross profit	95,842	112,411
Operating expenses
Selling, general and administrative	42,215	43,688
Research and development	23,678	22,170
Amortization of acquisition related intangible assets	4,221	4,484
Other operating (income)	(124)	(54)
Total operating expense	69,990	70,288
Income from operations	25,852	42,123
Other income (expense)
Interest income	273	875
Interest expense	(1,245)	(2,145)
Foreign currency gain (loss), net	75	(64)
Other income	1	1,245
Total other income (expense)	(896)	(89)
Income before income taxes and noncontrolling interest	24,956	42,034
Income tax provision	4,556	10,298
Net income	20,400	31,736
Less net (income) attributable to noncontrolling interest	(232)	(20)
Net income attributable to common stockholders	$ 20,168	$ 31,716
Earnings per share attributable to common stockholders:
Basic	$ 0.39	$ 0.63
Diluted	$ 0.38	$ 0.62
Number of shares used in earnings per share computation:
Basic	51,335	50,398
Diluted	52,422	51,462