CONSOLIDATED BALANCE SHEETS - USD ($)	Apr. 30, 2016	Apr. 30, 2015
CURRENT ASSETS:
Cash and cash equivalents	$ 61,412,000	$ 68,001,000
Trade and other receivables, net	2,859,000	3,813,000
Inventories	16,186,000	7,354,000
Prepaid expenses and other current assets, net	1,351,000	1,355,000
Total current assets	81,808,000	80,523,000
PROPERTY AND EQUIPMENT:
Leasehold improvements	19,610,000	1,538,000
Laboratory equipment	10,257,000	5,965,000
Furniture, fixtures, office equipment and software	4,045,000	3,991,000
Construction-in-progress	0	11,819,000
Property and equipment, gross	33,912,000	23,313,000
Less accumulated depreciation and amortization	(9,610,000)	(8,189,000)
Property and equipment, net	24,302,000	15,124,000
Restricted cash	600,000	0
Other assets	2,333,000	1,817,000
TOTAL ASSETS	109,043,000	97,464,000
CURRENT LIABILITIES:
Accounts payable	8,429,000	10,385,000
Accrued clinical trial and related fees	7,594,000	3,910,000
Accrued payroll and related costs	5,821,000	4,606,000
Deferred revenue	10,030,000	6,630,000
Customer deposits	24,212,000	11,363,000
Other current liabilities	1,488,000	437,000
Total current liabilities	57,574,000	37,331,000
Deferred rent, less current portion	1,395,000	1,098,000
Commitments and contingencies
STOCKHOLDERS' EQUITY:
Preferred stock - $.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 - $.001 par value; authorized 500,000,000 shares; issued and outstanding - 236,930,485 and 193,346,627, respectively	237,000	193,000
Additional paid-in-capital	559,111,000	512,464,000
Accumulated deficit	(509,276,000)	(453,624,000)
Total stockholders' equity	50,074,000	59,035,000
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 109,043,000	$ 97,464,000

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

Name:	us-gaap_AccountsPayableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.