Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net change	$ 0	$ 7,000
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance at September 30, 2012	7,000
Balance at December 31, 2012	0
Net change	$ 7,000