Income Tax Expense (Benefit) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Income Taxes [Line Items]
Federal
State									956	350	256
International									518	767	233
Total									1,474	1,117	489
Federal									(16,705)	(7,488)	(6,183)
State									9	1	1
International									(90)	(282)	72
Total									(16,786)	(7,769)	(6,110)
Change in valuation allowance									14,165	7,463	6,182
Provision for (benefit from) income taxes	$ 584	$ (2,293)	$ 274	$ 288	$ 343	$ 181	$ 178	$ 109	$ (1,147)	$ 811	$ 561