Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended					12 Months Ended				12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009	Dec. 31, 2012 Subsequent Event	Sep. 30, 2012 U.S. federal	Sep. 30, 2012 State	Sep. 30, 2012 Foreign NOL carryforwards	Sep. 30, 2012 CA state research credit	Sep. 30, 2011 Federal Research and Development
Income Taxes [Line Items]
Foreign pretax earnings	$ 26,900,000	$ 20,600,000	$ 25,300,000
Current foreign tax expense related to foreign tax withholdings	6,300,000	5,400,000	2,300,000
Net operating loss carryforwards						32,700,000	7,500,000	43,300,000
Excess state research credit									2,300,000
Net operating loss carryforwards expiration dates						Fiscal 2024	Fiscal 2021
U.S. federal statutory income tax rate	35.00%	35.00%	35.00%
The sum of credits that impacted the effective tax rate positively during the fiscal year 2011										1,100,000
Excess amount for financial reporting over tax basis of investments in foreign subsidiaries					47,000,000
Unrecognized tax benefits	7,501,000	9,539,000	12,286,000	18,587,000
Unrecognized tax benefits that would impact the effective tax rate if recognized	5,900,000
Unrecognized tax benefits that will settle over the next 12 months	3,100,000
Unrecognized tax benefits, accrued interest	$ 700,000