CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($)	Jul. 31, 2015	Apr. 30, 2015
CURRENT ASSETS:
Cash and cash equivalents	$ 59,016,000	$ 68,001,000
Trade and other receivables, net	1,805,000	3,813,000
Inventories	10,457,000	7,354,000
Prepaid expenses and other current assets, net	1,052,000	1,355,000
Total current assets	72,330,000	80,523,000
Property and equipment, net	18,395,000	15,124,000
Other assets	1,307,000	1,817,000
TOTAL ASSETS	92,032,000	97,464,000
CURRENT LIABILITIES:
Accounts payable	9,840,000	10,385,000
Accrued clinical trial and related fees	4,106,000	3,910,000
Accrued payroll and related costs	3,094,000	4,606,000
Deferred revenue	8,291,000	6,630,000
Customer deposits	9,599,000	11,363,000
Other current liabilities	620,000	437,000
Total current liabilities	35,550,000	37,331,000
Deferred rent, less current portion	$ 1,036,000	$ 1,098,000
Commitments and contingencies
STOCKHOLDERS' EQUITY:
Preferred stock - $0.001 par value; authorized 5,000,000 shares; issued and outstanding - 1,574,764 and 1,574,764, respectively	$ 2,000	$ 2,000
Common stock-$0.001 par value; authorized 325,000,000 shares; issued and outstanding - 200,983,948 and 193,346,627, respectively	201,000	193,000
Additional paid-in-capital	522,590,000	512,464,000
Accumulated deficit	(467,347,000)	(453,624,000)
Total stockholders' equity	55,446,000	59,035,000
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 92,032,000	$ 97,464,000