Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Revenue	$ 45,538	$ 38,626	$ 90,109	$ 74,288
Cost of revenue	14,475	14,488	28,774	27,396
Gross profit	31,063	24,138	61,335	46,892
Operating expenses:
Sales and marketing	21,014	17,503	42,031	32,864
Research and development	10,024	8,237	19,140	15,936
General and administrative	3,959	7,153	12,888	22,830
Acquisition-related and other	8,283	1,366	15,787	2,750
Amortization of acquired intangible assets	1,305	898	2,609	1,378
Total operating expenses	44,585	35,157	92,455	75,758
Operating loss	(13,522)	(11,019)	(31,120)	(28,866)
Other income (expense), net:
Interest income	46		112	50
Other income (expense)	(295)	51	(354)	(403)
Total other income (expense), net	(249)	51	(242)	(353)
Loss before income taxes	(13,771)	(10,968)	(31,362)	(29,219)
Income tax expense	383	274	160	562
Net loss	$ (14,154)	$ (11,242)	$ (31,522)	$ (29,781)
Net loss per share:
Basic and diluted	$ (0.19)	$ (0.16)	$ (0.42)	$ (0.45)
Basic and diluted weighted average number of shares outstanding	75,088	69,846	74,535	66,203