Concentration of Credit Risk and Significant Customers - Additional Information (Detail)	3 Months Ended		6 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Mar. 31, 2012
Concentration Risk [Line Items]
Number of customers contributing to more than 10% of accounts receivable	1				0
Number of direct customer or indirect channel partner contributing more than 10% of total revenue	1	0	1	0