CONSOLIDATED INCOME STATEMENTS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Statement [Abstract]
Net sales	$ 142,389	$ 124,871	$ 393,220	$ 345,307
Cost of sales	101,940	88,433	282,386	247,572
Gross profit	40,449	36,438	110,834	97,735
Research and development expenses	4,182	3,521	12,463	10,408
Selling, general and administrative expenses	25,796	23,383	74,029	69,015
Operating income	10,471	9,534	24,342	18,312
Interest income (expense), net	47	(24)	60	(112)
Other income (expense), net	(717)	(65)	(2,897)	(515)
Income before provision for income taxes	9,801	9,445	21,505	17,685
Provision for income taxes	1,178	2,595	4,095	4,050
Net income	$ 8,623	$ 6,850	$ 17,410	$ 13,635
Earnings per share:
Basic (in dollars per share)	$ 0.56	$ 0.46	$ 1.15	$ 0.91
Diluted (in dollars per share)	$ 0.55	$ 0.45	$ 1.13	$ 0.90
Shares used in computing earnings per share:
Basic (in shares)	15,324	14,984	15,129	14,931
Diluted (in shares)	15,743	15,099	15,462	15,087