Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
	Jul. 31, 2014	Jul. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES
Net Loss	$ (2,171,412)	$ (2,245,272)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	38,486	37,300
Interest on debt instruments	45,606	628,321
Issuance and vesting of compensatory stock options and warrants	71,032	34,071
Issuance of common stock as compensation	14,840	13,261
Change in fair value of warrants	(274,196)	0
Amortization of premium on marketable securities	9,728	0
Changes in operating assets and liabilities
Accounts receivable, prepaid expenses and other assets	204,949	679,044
Inventory		268
Accounts payable and accrued liabilities	78,590	(710,135)
Net cash used in operating activities	(1,982,377)	(1,563,142)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of property and equipment	(35,627,219)	0
Sale of marketable securities	1,065,360	0
Capitalization of patent costs and license rights	(15,095)	(33,156)
Net cash used in investing activities	(34,576,954)	(33,156)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from sale of common stock and exercise of stock options and warrants, net of related expenses and payments	543,998	0
Proceeds from issuance of notes payable, net of issuance costs	0	4,920,183
Payments on notes - short-term	(347,561)	(34,372)
Net cash provided by financing activities	196,437	4,885,811
Net change in cash and cash equivalents	(36,362,894)	3,289,513
Cash and cash equivalents, beginning of period	58,320,555	783,528
Cash and cash equivalents, end of period	21,957,661	4,073,041
Cash paid for:
Interest	655	27,483
Non-cash financing activities:
Restricted stock issued during period in payment of interest on convertible notes	11,500	185,917
Common stock issued for payment of dividends on Series C Convertible Preferred stock	$ 0	$ 226,560