CONSOLIDATED BALANCE SHEETS (USD $)	Apr. 30, 2013	Apr. 30, 2012
CURRENT ASSETS:
Cash and cash equivalents	$ 35,204,000	$ 18,033,000
Trade and other receivables, net	1,662,000	2,353,000
Inventories	4,339,000	3,611,000
Prepaid expenses and other current assets, net	709,000	795,000
Total current assets	41,914,000	24,792,000
PROPERTY:
Leasehold improvements	1,383,000	1,383,000
Laboratory equipment	5,441,000	4,967,000
Furniture, fixtures, office equipment and software	2,627,000	2,287,000
Property, gross	9,451,000	8,637,000
Less accumulated depreciation and amortization	(6,773,000)	(5,737,000)
Property, net	2,678,000	2,900,000
Other assets	466,000	570,000
TOTAL ASSETS	45,058,000	28,262,000
CURRENT LIABILITIES:
Accounts payable	2,821,000	3,492,000
Accrued clinical trial and related fees	930,000	2,111,000
Accrued payroll and related costs	3,582,000	2,468,000
Deferred revenue, current portion	4,171,000	3,651,000
Customer deposits	8,059,000	4,865,000
Other current liabilities	998,000	1,052,000
Total current liabilities	20,561,000	17,639,000
Deferred revenue, less current portion	292,000	361,000
Other long-term liabilities	445,000	779,000
Commitments and contingencies
STOCKHOLDERS' EQUITY:
Preferred stock - $.001 par value; authorized 5,000,000 shares; non-voting; none issued	0	0
Common stock - $.001 par value; authorized 325,000,000 shares; outstanding - 143,768,946 and 101,421,365, respectively	143,000	101,000
Additional paid-in-capital	391,521,000	347,506,000
Accumulated deficit	(367,904,000)	(338,124,000)
Total stockholders' equity	23,760,000	9,483,000
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 45,058,000	$ 28,262,000