CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 30, 2012	Apr. 30, 2011
Operating activities:
Net loss	$ (8,661)	$ (3,802)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	3,323	3,133
Income tax (benefit) expense	(2)	11
Depreciation expense	105	42
Loss on disposal of property and equipment	0	1
Change in fair value of warrant liability	(417)	36
Changes in operating assets and liabilities:
Accounts receivable	1	(493)
Grant receivable	517	(517)
Prepaid expenses, deposits and other	71	217
Restricted cash	(150)	0
Accounts payable	96	636
Accrued liabilities	323	62
Deferred revenue	(433)	697
Other liabilities	0	(77)
Net cash used in operating activities	(5,227)	(54)
Investing activities:
Purchase of property and equipment	(519)	(85)
Proceeds form sale of property and equipment	0	1
Net cash used in investing activities	(519)	(84)
Financing activities:
Private placement of common shares and warrants (net of $305 in offering costs)	0	9,095
Purchase of treasury stock	0	(1,033)
Proceeds from exercise of options and warrants	97	21
Net cash provided by financing activities	97	8,083
Exchange rate effect on cash and cash equivalents	(54)	(60)
Increase (decrease) in cash and cash equivalents	(5,703)	7,885
Cash and cash equivalents, beginning of year	10,457	2,572
Cash and cash equivalents, end of year	$ 4,754	$ 10,457