Condensed Consolidated Statements of Comprehensive Loss (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012
Net loss	$ (10,827)	$ (6,575)	$ (40,608)	$ (17,962)
Other comprehensive gain (loss), net of tax:
Foreign currency translation adjustment	(21)	(44)	(30)	(80)
Unrealized gain (loss) on investments	(6)		17
Total other comprehensive loss, net of tax	(27)	(44)	(13)	(80)
Comprehensive loss	$ (10,854)	$ (6,619)	$ (40,621)	$ (18,042)