CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
NET SALES	$ 603,838	$ 542,149	$ 509,689
COST OF SALES	338,813	306,368	284,467
GROSS PROFIT	265,025	235,781	225,222
OPERATING EXPENSES:
Selling, general and administrative	184,398	156,348	147,894
Research and development	45,229	40,810	36,632
Intangible asset impairment charges	0	0	1,102
Contingent consideration expense (benefit)	61	80	(572)
Acquired in-process research and development	461	1,000	0
Total operating expenses	230,149	198,238	185,056
INCOME FROM OPERATIONS	34,876	37,543	40,166
OTHER INCOME (EXPENSE):
Interest income	81	272	217
Interest expense	(8,798)	(6,229)	(8,829)
Other income (expense) — net	(773)	(386)	18
Other expense — net	(9,490)	(6,343)	(8,594)
INCOME BEFORE INCOME TAXES	25,386	31,200	31,572
INCOME TAX EXPENSE	5,265	7,398	8,598
NET INCOME	$ 20,121	$ 23,802	$ 22,974
EARNINGS PER COMMON SHARE:
Basic (in dollars per share)	$ 0.45	$ 0.54	$ 0.53
Diluted (in dollars per share)	$ 0.45	$ 0.53	$ 0.53
AVERAGE COMMON SHARES:
Basic (in shares)	44,408	44,036	43,143
Diluted (in shares)	44,862	44,511	43,409