Income Taxes - Reconciliation of the Federal Statutory Rate to Effective Income Tax Rate (Detail)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Abstract]
Federal statutory rate	(34.00%)	(34.00%)	(34.00%)
Increase in deferred income tax asset valuation allowance	37.00%	31.00%	34.00%
State income taxes, net of federal effect	(5.00%)	(5.00%)	(4.00%)
Research and development credits	3.00%	1.00%	0.00%
Expired net operating loss and other credits		6.00%	4.00%
Other	(1.00%)	1.00%	0.00%
Effective income tax rate	0.00%	0.00%	0.00%