Quarterly Financial Data (Details) (USD $)	3 Months Ended																12 Months Ended
	Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2011		Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Quarterly Financial Information Disclosure [Abstract]
Total revenue	$ 51,369,000		$ 48,824,000		$ 48,197,000		$ 46,991,000		$ 47,248,000		$ 47,632,000		$ 49,016,000		$ 46,662,000		$ 195,381,000	$ 190,558,000	$ 204,160,000
Gross profit	25,963,000		24,720,000		24,961,000		24,479,000		24,820,000		25,304,000		25,783,000		24,430,000		100,123,000	100,337,000	106,588,000
Net income	2,047,000	[1],[2],[3],[4]	1,528,000	[1],[2],[3],[4]	1,000,000	[1],[2],[3],[4]	1,230,000	[1],[2],[3],[4]	2,462,000	[1],[2]	2,307,000	[1],[2]	2,122,000	[1],[2]	724,000	[1],[2]	5,805,000	7,615,000	11,019,000
Net income per common share, basic (USD per share)	$ 0.08		$ 0.06		$ 0.04		$ 0.05		$ 0.10		$ 0.09		$ 0.08		$ 0.03		$ 0.22	$ 0.30	$ 0.44
Net income per common share, diluted (USD per share)	$ 0.08		$ 0.06		$ 0.04		$ 0.05		$ 0.09		$ 0.09		$ 0.08		$ 0.03		$ 0.22	$ 0.29	$ 0.43
Discrete tax benefit [Abstract]
Discrete tax benefit	200,000		100,000		400,000		100,000		300,000		1,100,000				100,000		800,000	1,500,000	700,000
Restructuring Charges [Abstract]
Restructuring charge	400,000										1,000,000		100,000		200,000		313,000	1,259,000	154,000
Restructuring accrual, net of tax	200,000										600,000		0		200,000
Litigation Settlement [Abstract]
Litigation Settlement (charge)					1,500,000
Litigation settlement amount (charge), net of tax					1,000,000
Impairment of Intangible Assets (Excluding Goodwill) [Abstract]
Intangible impairment charge	361,000																361,000	0	0
Intangible impairment charge, net of taxes	$ 200,000

[1] During fiscal 2013, we recorded a business restructuring accrual of $0.4 million ($0.2 million after tax) in the fourth quarter of fiscal 2013. During fiscal 2012, we recorded a business restructuring accrual of $0.2 million ($0.2 million after tax) in the first quarter, $0.1 million ($0.0 million after tax) in the second quarter and $1.0 million ($0.6 million after tax) in the third quarter.

[2] During fiscal 2013 and 2012, we recorded discrete tax benefits of $0.8 million and $1.5 million, respectively. We recorded a benefit of $0.1 million in the first quarter of fiscal 2013 resulting from the release of income tax reserves due to the expiration of the statute of limitations from various U.S. and foreign tax jurisdictions. During the second quarter of fiscal 2013, we recorded a discrete tax benefit of $0.4 million resulting from the enactment of legislation on January 2, 2013 extending the research and development credit for the last three quarters of fiscal 2012. In the third quarter of fiscal 2013, we recorded a benefit of $0.1 million for the release of income tax reserves due to the expiration of the statute of limitations for U.S. Federal income tax for fiscal 2009. In the fourth quarter of fiscal 2013, we recorded $0.2 million for the reversal of tax reserves resulting from expiration of the statute of limitations for state income taxes. We recorded a benefit of $0.1 million in the first quarter of fiscal 2012 resulting from the release of income tax reserves due to the expiration of the statute of limitations from various U.S. tax jurisdictions. During the third quarter of fiscal 2012, we recorded $1.1 million for additional research and development tax credits identified for fiscal years ended September 30, 2009, 2010 and 2011 from a recently completed research and development tax credit study. During the fourth quarter of fiscal 2012, we recorded $0.3 million relating to expiration of statute of limitations for state income taxes and a reduction in a foreign statutory rate.

[3] During the second quarter of fiscal 2013, we recorded a charge of $1.5 million ($1.0 million after tax) for the settlement of a patent infringement lawsuit.

[4] During the fourth quarter of fiscal 2013, we recorded a charge of $0.4 million ($0.2 million after tax) for impairment of certain intangibles.