Income Tax - Additional Information (Detail) (USD $)	12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Income Taxes [Line Items]
Federal, state and foreign net operating loss carryforwards	$ 433,000,000
Federal and state research and development tax credit carryforwards	22,700,000
Tax benefits from Federal, state and foreign net operating loss carryforwards	119,167,000	139,464,000
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 2029.
Unrecognized tax benefits, which if recognized, would affect the effective tax rate	9,800,000	12,500,000	11,500,000
Unrecognized tax benefits that would not impact the effective tax rate	1,200,000	2,500,000
Interest related to unrecognized benefits	400,000	400,000	300,000
Reductions from settlements with taxing authorities	4,002,000	197,000	528,000
Reduction in gross unrecognized tax benefits	2,800,000
Anticipated unrecognized tax benefit reduction during the next twelve months	3,600,000
Additional Paid-in Capital | Stock options
Income Taxes [Line Items]
Tax benefits from Federal, state and foreign net operating loss carryforwards	4,000,000
Stock options
Income Taxes [Line Items]
Federal, state and foreign net operating loss carryforwards	19,500,000
Tax benefits from Federal, state and foreign net operating loss carryforwards	$ 7,000,000