Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($)	Preferred Stock - Series F [Member]	Preferred Stock - Series G [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Total
Balance at Apr. 30, 2019			$ 1,986	$ 33,425,931	$ (26,275,102)	$ 7,152,815
Balance, shares at Apr. 30, 2019			1,986,063
Issuance of preferred stock and warrants for cash, net of offering cost	$ 1			2,401,201		2,401,202
Issuance of preferred stock and warrants for cash, net of offering cost, shares	1,250
Conversion of preferred stock into common stock			$ 108	(108)
Conversion of preferred stock into common stock, shares	(616)		108,071
Issuance of common stock for services			$ 2	24,998		25,000
Issuance of common stock for services, shares			2,153
Issuance of common stock for accrued services			$ 1	12,499		12,500
Issuance of common stock for accrued services, shares			1,068
Stock options granted for services				52,214		52,214
Stock-based compensation in connection with restricted common stock award grants and restricted common stock unit grants				52,682		52,682
Stock-based compensation in connection with restricted common stock award grants and restricted common stock unit grants, shares
Cancellation of common stock			$ (9)	9
Cancellation of common stock, shares			(8,500)
Deemed dividends - series F preferred stock				2,022,712	(2,022,712)	2,022,712
Net loss					(1,308,599)	(1,308,599)
Balance at Jul. 31, 2019	$ 1		$ 2,088	37,992,138	(29,606,413)	8,387,814
Balance, shares at Jul. 31, 2019	634		2,088,855
Balance at Apr. 30, 2020			$ 2,903	41,093,050	(31,587,952)	9,508,001
Balance, shares at Apr. 30, 2020		57	2,903,393
Conversion of preferred stock into common stock			$ 21	(21)
Conversion of preferred stock into common stock, shares		(57)	20,357
Stock options granted for services				51,262		51,262
Stock-based compensation in connection with restricted common stock award grants and restricted common stock unit grants			$ 2	20,216		20,218
Stock-based compensation in connection with restricted common stock award grants and restricted common stock unit grants, shares			1,875
Deemed dividends - series F preferred stock
Net loss					(957,120)	(957,120)
Balance at Jul. 31, 2020			$ 2,926	$ 41,164,507	$ (32,545,072)	$ 8,622,361
Balance, shares at Jul. 31, 2020			2,925,625