Income Taxes (Details) (USD $)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Income tax
Deferred tax position	$ 32,076,000	$ 17,309,000		$ 0
Income tax expense	3,924,000	661,000	(171,000)
Estimated effective income tax rate (as a percent)	32.00%	(3.00%)	0.00%
Period of cumulative accounting profit that may be realized	3 years
Net operating loss carryforwards	78,100,000
Tax credit carryforwards	$ 25,600,000
Minimum
Income tax
Operating loss carryforwards expiration date	Sep. 30, 2014
Tax credit carryforwards, expiration date	Sep. 30, 2014
Maximum
Income tax
Operating loss carryforwards expiration date	Sep. 30, 2033
Tax credit carryforwards, expiration date	Sep. 30, 2033