CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($)	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Deficit
Balance at Apr. 30, 2015	$ 8,059,000	$ 9,000	$ (1,252,000)	$ 61,322,000	$ (52,020,000)
Balance (in shares) at Apr. 30, 2015		8,692,616	269,685
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation and modification expense	2,599,000			2,599,000
Exercise of options and warrants	(18,000)			(18,000)
Exercise of options and warrants (in shares)		0
Issuance of common stock for services	44,000			44,000
Issuance of common stock (in shares)		12,230
Net loss	(10,445,537)				(10,446,000)
Balance at Apr. 30, 2016	238,000	$ 9,000	$ (1,252,000)	63,947,000	(62,466,000)
Balance (in shares) at Apr. 30, 2016		8,704,846	269,685
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation and modification expense	2,662,000			2,662,000
Issuance of common stock for services	44,000			44,000
Issuance of common stock (in shares)		18,564
Sale of common stock, net of issuance costs of $742	4,340,000	$ 2,000	$ 0	4,338,000	0
Sale of common stock, net of issuance costs of $742 (in shares)		2,258,749	0
Net loss	(6,883,882)				(6,884,000)
Balance at Apr. 30, 2017	$ 400,000	$ 11,000	$ (1,252,000)	$ 70,991,000	$ (69,350,000)
Balance (in shares) at Apr. 30, 2017		10,982,159	269,685