UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Oct. 31, 2011	Oct. 31, 2010
Operating activities:
Net loss	$ (4,387)	$ (645)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	1,868	367
Depreciation expense	49	20
Change in fair value of warrant liability	(288)	0
Changes in operating assets and liabilities:
Accounts receivable	(247)	(289)
Grant receivable	0	(960)
Prepaid expenses, deposits and other	(52)	242
Restricted cash	(150)	0
Accounts payable	(286)	438
Accrued liabilities	(79)	(23)
Deferred revenue	281	(336)
Net cash used in operating activities	(3,291)	(1,186)
Investing activities:
Purchase of property and equipment	(160)	(25)
Net cash used in investing activities	(160)	(25)
Financing activities:
Purchase of treasury stock	0	(73)
Proceeds from exercise of warrants	98	0
Net cash provided by (used in) financing activities	98	(73)
Exchange rate effect on cash and cash equivalents	15	(25)
Decrease in cash and cash equivalents	(3,338)	(1,309)
Cash and cash equivalents, beginning of period	10,457	2,572
Cash and cash equivalents, end of period	$ 7,119	$ 1,263