CONSOLIDATED INCOME STATEMENTS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Statement [Abstract]
Net sales	$ 146,315	$ 136,109	$ 276,160	$ 250,831
Cost of sales	102,757	98,273	196,056	180,446
Gross profit	43,558	37,836	80,104	70,385
Research and development expenses	4,119	4,040	8,396	8,281
Selling, general and administrative expenses	27,765	23,820	54,044	48,233
Operating income	11,674	9,976	17,664	13,871
Interest income (expense), net	(71)	4	(87)	13
Other income (expense), net	(334)	(1,630)	(683)	(2,180)
Income before provision for income taxes	11,269	8,350	16,894	11,704
Provision for income taxes	2,781	2,509	4,133	2,917
Net income	$ 8,488	$ 5,841	$ 12,761	$ 8,787
Earnings per share:
Basic (in dollars per share)	$ 0.54	$ 0.39	$ 0.81	$ 0.58
Diluted (in dollars per share)	$ 0.53	$ 0.38	$ 0.79	$ 0.57
Shares used in computing earnings per share:
Basic (in shares)	15,784	15,098	15,785	15,032
Diluted (in shares)	16,141	15,419	16,151	15,322