Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2013
Schedule Of Income Taxes [Line Items]
Operating loss and research credit carryforward expiration period	2029
Operating loss and research and development credit carryforwards	Pursuant to Internal Revenue Code ("IRC") Sections 382 and 383, annual use of the Company's net operating loss and research and development credit carryforwards may be limited in the event of a cumulative change in ownership of more than 50% within a three-year period.
Domestic Tax Authority [Member]
Schedule Of Income Taxes [Line Items]
Net operating loss carryforward	$ 407.4
Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member]
Schedule Of Income Taxes [Line Items]
Research and development carryforward	7.8
State and Local Jurisdiction [Member]
Schedule Of Income Taxes [Line Items]
Net operating loss carryforward	356.1
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member]
Schedule Of Income Taxes [Line Items]
Research and development carryforward	6.8
Foreign Tax Authority [Member]
Schedule Of Income Taxes [Line Items]
Research and development carryforward	$ 0