CONSOLIDATED INCOME STATEMENTS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Statement [Abstract]
Net sales	$ 136,109	$ 116,704	$ 250,831	$ 220,436
Cost of sales	98,273	83,734	180,446	159,139
Gross profit	37,836	32,970	70,385	61,297
Research and development expenses	4,040	3,424	8,281	6,887
Selling, general and administrative expenses	23,820	23,080	48,233	45,632
Operating income	9,976	6,466	13,871	8,778
Interest income (expense), net	4	(51)	13	(88)
Other income (expense), net	(1,630)	(126)	(2,180)	(450)
Income before provision for income taxes	8,350	6,289	11,704	8,240
Provision for income taxes	2,509	1,136	2,917	1,455
Net income	$ 5,841	$ 5,153	$ 8,787	$ 6,785
Earnings per share:
Basic (in dollars per share)	$ 0.39	$ 0.35	$ 0.58	$ 0.46
Diluted (in dollars per share)	$ 0.38	$ 0.34	$ 0.57	$ 0.45
Shares used in computing earnings per share:
Basic (in shares)	15,098	14,933	15,032	14,904
Diluted (in shares)	15,419	15,048	15,322	15,080