CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($)	Oct. 31, 2015	Apr. 30, 2015
CURRENT ASSETS:
Cash and cash equivalents	$ 72,005,000	$ 68,001,000
Trade and other receivables, net	2,904,000	3,813,000
Inventories	12,554,000	7,354,000
Prepaid expenses and other current assets, net	1,995,000	1,355,000
Total current assets	89,458,000	80,523,000
Property and equipment, net	21,764,000	15,124,000
Other assets	1,435,000	1,817,000
TOTAL ASSETS	112,657,000	97,464,000
CURRENT LIABILITIES:
Accounts payable	6,901,000	10,385,000
Accrued clinical trial and related fees	6,138,000	3,910,000
Accrued payroll and related costs	4,130,000	4,606,000
Deferred revenue	9,688,000	6,630,000
Customer deposits	14,935,000	11,363,000
Other current liabilities	667,000	437,000
Total current liabilities	42,459,000	37,331,000
Deferred rent, less current portion	$ 972,000	$ 1,098,000
Commitments and contingencies
STOCKHOLDERS' EQUITY:
Preferred stock - $0.001 par value; authorized 5,000,000 shares; issued and outstanding - 1,577,440 and 1,574,764, respectively	$ 2,000	$ 2,000
Common stock-$0.001 par value; authorized 500,000,000 shares; issued and outstanding - 225,824,551 and 193,346,627, respectively	226,000	193,000
Additional paid-in-capital	549,543,000	512,464,000
Accumulated deficit	(480,545,000)	(453,624,000)
Total stockholders' equity	69,226,000	59,035,000
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 112,657,000	$ 97,464,000