Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2011	Oct. 31, 2010
Revenue
Product revenue	$ 1,179	$ 1,758	$ 2,376	$ 4,099
Service revenue	2,025	1,894	4,517	3,592
Total revenue	3,204	3,652	6,893	7,691
Cost of revenue
Product revenue	686	937	1,533	2,011
Service revenue	1,476	1,325	2,833	2,490
Total cost of revenue	2,162	2,262	4,366	4,501
Gross profit	1,042	1,390	2,527	3,190
Operating expenses:
Sales and marketing	1,368	1,904	2,746	3,934
Research and development	1,758	1,917	3,610	4,105
General and administrative	940	1,128	2,003	2,563
Amortization of purchased intangible assets	20	20	40	40
Total operating expenses	4,086	4,969	8,399	10,642
Loss from operations	(3,044)	(3,579)	(5,872)	(7,452)
Other income (expense), net	8	(15)	(11)	(24)
Loss before provision for (benefit from) income taxes	(3,036)	(3,594)	(5,883)	(7,476)
Provision for (benefit from) income taxes	(3)	(18)	12	(17)
Net loss	$ (3,033)	$ (3,576)	$ (5,895)	$ (7,459)
Basic and diluted:
Net loss (in dollars per share)	$ (0.11)	$ (0.14)	$ (0.22)	$ (0.28)
Weighted shares used in per share calculation:
Basic (in shares)	26,421	26,352	26,420	26,349
Diluted (in shares)	26,421	26,352	26,420	26,349