CONDENSED CONSOLIDATED BALANCE SHEETS (USD $)	Oct. 31, 2013	Apr. 30, 2013
CURRENT ASSETS:
Cash and cash equivalents	$ 44,443,000	$ 35,204,000
Trade and other receivables, net	1,936,000	1,662,000
Inventories	4,033,000	4,339,000
Prepaid expenses and other current assets, net	874,000	709,000
Total current assets	51,286,000	41,914,000
Property and equipment, net	2,315,000	2,678,000
Other assets	1,506,000	466,000
TOTAL ASSETS	55,107,000	45,058,000
CURRENT LIABILITIES:
Accounts payable	2,371,000	2,821,000
Accrued clinical trial and related fees	1,029,000	930,000
Accrued payroll and related costs	3,152,000	3,582,000
Deferred revenue, current portion	3,468,000	4,171,000
Customer deposits	7,658,000	8,059,000
Other current liabilities	1,089,000	998,000
Total current liabilities	18,767,000	20,561,000
Deferred revenue, less current portion	292,000	292,000
Other long-term liabilities	399,000	445,000
Commitments and contingencies (Note 11)
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 - 160,248,742 and 143,768,946, respectively	160,000	143,000
Additional paid-in-capital	418,783,000	391,521,000
Accumulated deficit	(383,294,000)	(367,904,000)
Total stockholders' equity	35,649,000	23,760,000
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 55,107,000	$ 45,058,000