Significant Customers - Additional Information (Detail)	12 Months Ended
	Sep. 30, 2011 Year Month Person Entity	Sep. 30, 2010 Entity Month	Sep. 30, 2009 Month Person Entity
Segment Reporting Disclosure [Line Items]
Number of major customer by revenue	2	3	1
Number of major customer description	The Company had two customers that each accounted for more than 10% of revenues, at 15% and 13%, respectively, in the year ended September 30, 2011.	The Company had three customers that each accounted for more than 10% of revenues, at 21%, 15% and 10%, respectively, in the year ended September 30, 2010.	The Company had one customer that accounted for more than 10% of revenues, at 14%, in the year ended September 30, 2009.
Number of major customer by accounts receivable		1
Customer 1
Segment Reporting Disclosure [Line Items]
Percentage of revenues by customer	15.00%	21.00%	14.00%
Customer 2
Segment Reporting Disclosure [Line Items]
Percentage of revenues by customer	13.00%	15.00%
Customer 3
Segment Reporting Disclosure [Line Items]
Percentage of revenues by customer		10.00%
Accounts Receivable
Segment Reporting Disclosure [Line Items]
Number of major customer description	The Company did not have any customers that accounted for more than 10% of its accounts receivable balance at September 30, 2011.	The Company had one customer that accounted for more than 10% of its accounts receivable balance at September 30, 2010.