Consolidated Statements Of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements Of Operations [Abstract]
Sales	$ 43,281	$ 43,101
Cost of sales	22,623	24,008
Gross profit	20,658	19,093
Operating expenses:
Selling, general and administrative expenses	4,735	4,442
Research and development expenses	2,889	2,940
Bad debt expense (recovery)	436	(70)
Total operating expenses	8,060	7,312
Gain on disposal of equipment		16
Income from operations	12,598	11,797
Other income (expense):
Interest expense		(43)
Interest income	267	62
Foreign exchange gains	122	140
Other, net	(55)	(20)
Total other income, net	334	139
Income before income taxes	12,932	11,936
Income tax expense	4,247	3,723
Net income	$ 8,685	$ 8,213
Basic earnings per common share	$ 1.37	$ 1.34
Diluted earnings per common share	$ 1.35	$ 1.30
Weighted average common shares outstanding-Basic	6,352,269	6,118,666
Weighted average common shares outstanding-Diluted	6,417,548	6,306,718