| CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($)
 | Common Stock [Member] | Additional Paid-in Capital [Member] | Retained Earnings [Member] | AOCI Attributable to Parent [Member] | Total | 
| Beginning balance, value at Apr. 30, 2020 | $ 109 | $ 108,968,817 | $ (103,858,259) | $ (21,709) | $ 5,088,958 | 
| Beginning balance, shares at Apr. 30, 2020 | 1,092,425 |  |  |  |  | 
| Stock issued for compensation |  | 67,320 |  |  | 67,320 | 
| Stock issued for services |  | 40,550 |  |  | 40,550 | 
| Stock issued for services, shares | 1,667 |  |  |  |  | 
| Stock issued for cash, net of issuance costs of $278,150 | $ 16 | 1,857,381 |  |  | 1,857,397 | 
| Stock issued for cash, net of issuance costs, shares | 156,004 |  |  |  |  | 
| Stock-based compensation options |  | 72,317 |  |  | 72,317 | 
| Foreign currency translation adjustment |  |  |  | 2,677 | 2,677 | 
| Net loss |  |  | (883,944) |  | (883,944) | 
| Ending balance, value at Jul. 31, 2020 | $ 125 | 111,006,385 | (104,742,203) | (19,032) | 6,245,275 | 
| Ending balance, shares at Jul. 31, 2020 | 1,250,096 |  |  |  |  | 
| Beginning balance, value at Apr. 30, 2020 | $ 109 | 108,968,817 | (103,858,259) | (21,709) | 5,088,958 | 
| Beginning balance, shares at Apr. 30, 2020 | 1,092,425 |  |  |  |  | 
| Ending balance, value at Oct. 31, 2020 | $ 156 | 113,990,642 | (105,692,395) | (21,884) | 8,276,619 | 
| Ending balance, shares at Oct. 31, 2020 | 1,556,540 |  |  |  |  | 
| Beginning balance, value at Jul. 31, 2020 | $ 125 | 111,006,385 | (104,742,203) | (19,032) | 6,245,275 | 
| Beginning balance, shares at Jul. 31, 2020 | 1,250,096 |  |  |  |  | 
| Stock issued for compensation |  | 67,320 |  |  | 67,320 | 
| Stock issued for services |  | 19,159 |  |  | 19,159 | 
| Stock issued for services, shares | 667 |  |  |  |  | 
| Stock issued for cash, net of issuance costs of $278,150 | $ 31 | 2,841,819 |  |  | 2,841,850 | 
| Stock issued for cash, net of issuance costs, shares | 305,777 |  |  |  |  | 
| Stock-based compensation options |  | 56,059 |  |  | 56,059 | 
| Foreign currency translation adjustment |  |  |  | (2,852) | (2,852) | 
| Net loss |  |  | (950,192) |  | (950,192) | 
| Ending balance, value at Oct. 31, 2020 | $ 156 | 113,990,642 | (105,692,395) | (21,884) | 8,276,619 | 
| Ending balance, shares at Oct. 31, 2020 | 1,556,540 |  |  |  |  | 
| Beginning balance, value at Apr. 30, 2021 | $ 159 | 114,109,169 | (107,409,495) | (20,382) | 6,679,451 | 
| Beginning balance, shares at Apr. 30, 2021 | 1,590,084 |  |  |  |  | 
| Stock issued for compensation |  | 11,055 |  |  | 11,055 | 
| Stock issued for services |  | 24,765 |  |  | 24,765 | 
| Stock issued for services, shares | 1,336 |  |  |  |  | 
| Stock issued fractions shares -reverse stock split 1 for 1,500 | $ 2 | (2) |  |  |  | 
| Stock issued fractions shares -reverse stock split 1 for 1,500, shares | 20,251 |  |  |  |  | 
| Stock-based compensation options |  | 24,144 |  |  | 24,144 | 
| Foreign currency translation adjustment |  |  |  | (1,615) | (1,615) | 
| Net loss |  |  | (1,025,418) |  | (1,025,418) | 
| Ending balance, value at Jul. 31, 2021 | $ 161 | 114,169,131 | (108,434,913) | (21,997) | 5,712,382 | 
| Ending balance, shares at Jul. 31, 2021 | 1,611,671 |  |  |  |  | 
| Beginning balance, value at Apr. 30, 2021 | $ 159 | 114,109,169 | (107,409,495) | (20,382) | 6,679,451 | 
| Beginning balance, shares at Apr. 30, 2021 | 1,590,084 |  |  |  |  | 
| Ending balance, value at Oct. 31, 2021 | $ 2,072 | 201,555,275 | (109,414,659) | (19,091) | 92,123,597 | 
| Ending balance, shares at Oct. 31, 2021 | 20,715,804 |  |  |  |  | 
| Beginning balance, value at Jul. 31, 2021 | $ 161 | 114,169,131 | (108,434,913) | (21,997) | 5,712,382 | 
| Beginning balance, shares at Jul. 31, 2021 | 1,611,671 |  |  |  |  | 
| Stock issued for compensation |  | 11,055 |  |  | 11,055 | 
| Stock issued for services |  | 4,566 |  |  | 4,566 | 
| Stock issued for services, shares | 668 |  |  |  |  | 
| Stock issued for cash, net of issuance costs of $278,150 | $ 1,911 | 82,611,089 |  |  | 82,613,000 | 
| Stock issued for cash, net of issuance costs, shares | 19,101,812 |  |  |  |  | 
| Stock issued fractions shares -reverse stock split 1 for 1,500 |  |  |  |  |  | 
| Stock issued fractions shares -reverse stock split 1 for 1,500, shares | 1,653 |  |  |  |  | 
| Stock-based compensation options |  | 10,384 |  |  | 10,384 | 
| Issuance of pre-funded warrants |  | 4,749,050 |  |  | 4,749,050 | 
| Foreign currency translation adjustment |  |  |  | 2,906 | 2,906 | 
| Net loss |  |  | (979,746) |  | (979,746) | 
| Ending balance, value at Oct. 31, 2021 | $ 2,072 | $ 201,555,275 | $ (109,414,659) | $ (19,091) | $ 92,123,597 | 
| Ending balance, shares at Oct. 31, 2021 | 20,715,804 |  |  |  |  |