UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jul. 31, 2012	Jul. 31, 2011
Operating activities:
Net loss	$ (1,323)	$ (2,037)
Adjustments to reconcile net loss to net cashx used in operating activities:
Stock-based compensation expense	739	1,014
Depreciation expense	54	29
Change in fair value of warrant liability	(285)	(177)
Changes in operating assets and liabilities:
Accounts receivable	(55)	(651)
Grant receivable	0	13
Prepaid expenses, deposits and other	(3)	(65)
Accounts payable	(385)	(82)
Accrued liabilities	(281)	(38)
Deferred revenue	(267)	459
Net cash used in operating activities	(1,806)	(1,535)
Investing activities:
Purchase of property and equipment	(19)	(95)
Net cash used in investing activities	(19)	(95)
Financing activities:
Proceeds from exercise of options and warrants	0	4
Net cash provided by financing activities	0	4
Exchange rate effect on cash and cash equivalents	25	8
Decrease in cash and cash equivalents	(1,800)	(1,618)
Cash and cash equivalents, beginning of period	4,716	10,457
Cash and cash equivalents, end of period	$ 2,916	$ 8,839