CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Net sales	$ 323,674	$ 320,946	$ 947,973	$ 899,543
Cost of goods sold	201,628	205,732	591,528	578,466
Gross profit	122,046	115,214	356,445	321,077
Operating expenses
Selling, general and administrative	46,123	42,475	137,143	131,778
Research and development	22,689	22,549	66,566	64,799
Amortization of acquisition related intangible assets	4,519	4,418	13,539	13,863
Other operating (income) expense		(66)	(158)	15
Total operating expense	73,331	69,376	217,090	210,455
Income from operations	48,715	45,838	139,355	110,622
Other income (expense)
Interest income	272	474	1,780	1,431
Interest expense	(2,007)	(2,318)	(6,163)	(7,619)
Foreign currency (loss) gain, net	(822)	(655)	(1,382)	(3,384)
Other income	2,577	1,061	5,056	6,073
Total other income (expense)	20	(1,438)	(709)	(3,499)
Income before income taxes and noncontrolling interest	48,735	44,400	138,646	107,123
Income tax provision	10,613	13,190	32,085	31,726
Net income	38,122	31,210	106,561	75,397
Less net (income) attributable to noncontrolling interest	(62)	(302)	(501)	(895)
Net income attributable to common stockholders	$ 38,060	$ 30,908	$ 106,060	$ 74,502
Earnings per share attributable to common stockholders:
Basic	$ 0.75	$ 0.62	$ 2.09	$ 1.50
Diluted	$ 0.73	$ 0.61	$ 2.05	$ 1.46
Number of shares used in earnings per share computation:
Basic	50,998	50,115	50,687	49,713
Diluted	51,869	51,077	51,699	50,883