Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Income Taxes [Line Items]
Deferred income tax benefit	$ (122,136,000)	$ (276,000)
Federal, state and foreign net operating loss carryforwards	378,800,000
Federal and state research and development tax credit carryforwards	23,100,000
Federal and state research and development tax credit carryforwards, expiration year	2031
Net operating losses, expiration dates	U.S. net operating losses expire at various dates through 2030
Interest related to unrecognized benefits	200,000	400,000	400,000
Reductions from settlements with taxing authorities	3,700,000	4,002,000	197,000
Anticipated unrecognized tax benefit reduction during next twelve months	1,100,000
Stock Compensation Plan
Income Taxes [Line Items]
Federal, state and foreign net operating loss carryforwards	$ 12,500,000