CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME
Net sales	$ 56,583	$ 53,871	$ 106,327	$ 100,499
Cost of sales	28,433	26,883	54,036	50,253
Gross profit	28,150	26,988	52,291	50,246
Operating expenses
Selling, general and administrative	18,664	18,656	36,428	35,796
Amortization of intangible assets	573	471	1,145	945
Income from operations	8,913	7,861	14,718	13,505
Interest and other expense, net	377	377	688	736
Income before provision for income taxes	8,536	7,484	14,030	12,769
Provision for income taxes	3,000	2,654	5,000	4,528
Net income	5,536	4,830	9,030	8,241
Other comprehensive income (loss)
Foreign currency translation adjustment, net of tax	(162)	96	(157)	45
Comprehensive income	$ 5,374	$ 4,926	$ 8,873	$ 8,286
Net income per common share
Basic (in dollars per share)	$ 0.57	$ 0.49	$ 0.92	$ 0.82
Diluted (in dollars per share)	$ 0.57	$ 0.49	$ 0.92	$ 0.82
Weighted average common shares outstanding
Basic (in shares)	9,741,866	9,938,593	9,766,843	9,992,200
Dilutive effect of stock options (in shares)	30,671	8,419	28,911	11,651
Diluted (in shares)	9,772,537	9,947,012	9,795,754	10,003,851