CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
NET SALES	$ 882,753,000	$ 727,852,000	$ 603,838,000
COST OF SALES	487,983,000	401,599,000	338,813,000
GROSS PROFIT	394,770,000	326,253,000	265,025,000
OPERATING EXPENSES:
Selling, general and administrative	276,018,000	229,134,000	184,398,000
Research and development	59,532,000	51,403,000	45,229,000
Intangible asset impairment charges	657,000	809,000	0
Contingent consideration expense (benefit)	(698,000)	(298,000)	61,000
Acquired in-process research and development	644,000	12,136,000	461,000
Total operating expenses	336,153,000	293,184,000	230,149,000
INCOME FROM OPERATIONS	58,617,000	33,069,000	34,876,000
OTHER INCOME (EXPENSE):
Interest income	1,199,000	381,000	81,000
Interest expense	(10,360,000)	(7,736,000)	(8,798,000)
Gain on bargain purchase	0	11,039,000	0
Other income (expense) - net	63,000	(872,000)	(773,000)
Other income (expense) — net	(9,098,000)	2,812,000	(9,490,000)
INCOME BEFORE INCOME TAXES	49,519,000	35,881,000	25,386,000
INCOME TAX EXPENSE	7,502,000	8,358,000	5,265,000
NET INCOME	$ 42,017,000	$ 27,523,000	$ 20,121,000
EARNINGS PER COMMON SHARE:
Basic (in dollars per share)	$ 0.80	$ 0.56	$ 0.45
Diluted (in dollars per share)	$ 0.78	$ 0.55	$ 0.45
AVERAGE COMMON SHARES:
Basic (in shares)	52,268	48,805	44,408
Diluted (in shares)	53,931	50,101	44,862