Pro Forma Results of Operations (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Business Acquisition, Pro Forma Information [Line Items]
Net sales	$ 28,700	$ 26,240
Net income	$ 3,458	$ 1,140
Net income per share (basic)	$ 0.65	$ 0.22
Net income per share (diluted)	$ 0.64	$ 0.21