Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Income Statement [Abstract]
Net sales	$ 190,558	$ 204,160	$ 182,548
Cost of sales (exclusive of amortization of purchased and core technology shown separately below)	88,445	94,702	86,266
Amortization of purchased and core technology	1,776	2,870	4,073
Gross profit	100,337	106,588	92,209
Operating expenses:
Sales and marketing	39,242	39,549	37,010
Research and development	30,767	31,642	27,825
General and administrative	18,188	18,206	17,889
Restructuring	1,259	154	(468)
Total operating expenses	89,456	89,551	82,256
Operating income	10,881	17,037	9,953
Other income (expense), net:
Interest income	289	251	355
Interest expense	(23)	(86)	(138)
Other (expense) income	(250)	(687)	349
Total other income (expense), net	16	(522)	566
Income before income taxes	10,897	16,515	10,519
Income tax provision	3,282	5,496	1,578
Net income	$ 7,615	$ 11,019	$ 8,941
Net income per common share:
Basic	$ 0.30	$ 0.44	$ 0.36
Diluted	$ 0.29	$ 0.43	$ 0.36
Weighted average common shares:
Basic	25,743	25,312	24,865
Diluted	26,146	25,819	25,154