Employee Benefit Plans (Details) (USD $)	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
401 (k) plan
Employee benefit plan
Employer contribution that matches employee contributions (as a percent)	50.00%
Maximum match of employees salary (as a percent)	2.50%
Company contributions	$ 154,000	$ 149,000	$ 134,000
Group Personal Pension Scheme
Employee benefit plan
Company contributions	$ 252,000	$ 165,000	$ 65,000