CONDENSED CONSOLIDATED BALANCE SHEETS (USD $)	Jul. 31, 2011	Apr. 30, 2011
CURRENT ASSETS:
Cash and cash equivalents	$ 16,540,000	$ 23,075,000
Trade and other receivables, net	1,087,000	1,389,000
Government contract receivables	0	93,000
Inventories, net	4,481,000	5,284,000
Prepaid expenses and other current assets, net	853,000	974,000
Total current assets	22,961,000	30,815,000
Property, net	2,441,000	2,209,000
Other assets	1,613,000	1,742,000
TOTAL ASSETS	27,015,000	34,766,000
CURRENT LIABILITIES:
Accounts payable	2,959,000	4,046,000
Accrued clinical trial and related fees	2,786,000	2,292,000
Accrued payroll and related costs	1,532,000	1,455,000
Notes payable, current portion and net of discount	829,000	1,321,000
Deferred revenue	4,145,000	5,617,000
Customer deposits	289,000	1,759,000
Other current liabilities	1,253,000	1,189,000
Total current liabilities	13,793,000	17,679,000
Deferred revenue	554,000	632,000
Other long-term liabilities	871,000	1,037,000
Commitments and contingencies
STOCKHOLDERS' EQUITY:
Preferred stock-$0.001 par value; authorized 5,000,000 shares; non-voting; nil shares outstanding	0	0
Common stock-$0.001 par value; authorized 325,000,000 shares; outstanding – 71,749,718 and 69,837,142, respectively	72,000	70,000
Additional paid-in capital	315,822,000	311,353,000
Accumulated deficit	(304,097,000)	(296,005,000)
Total stockholders’ equity	11,797,000	15,418,000
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 27,015,000	$ 34,766,000