CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Income Statement [Abstract]
NET SALES	$ 119,236	$ 103,948
COST OF SALES	67,193	60,955
GROSS PROFIT	52,043	42,993
OPERATING EXPENSES:
Selling, general, and administrative	36,774	32,128
Research and development	8,780	9,108
Total operating expenses	45,554	41,236
INCOME FROM OPERATIONS	6,489	1,757
OTHER INCOME (EXPENSE):
Interest income	67	57
Interest (expense)	(2,606)	(1,539)
Other (expense) — net	(64)	(63)
Other expense — net	(2,603)	(1,545)
INCOME BEFORE INCOME TAXES	3,886	212
INCOME TAX EXPENSE (BENEFIT)	1,063	(459)
NET INCOME	$ 2,823	$ 671
EARNINGS PER COMMON SHARE:
Basic (in dollars per share)	$ 0.07	$ 0.02
Diluted (in dollars per share)	$ 0.07	$ 0.02
AVERAGE COMMON SHARES:
Basic (in shares)	42,865	42,520
Diluted (in shares)	43,234	42,835