Stockholders' Equity (Stock Options Narrative) (Details) - USD ($)
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|
|
6 Months Ended |
|
Sep. 06, 2018 |
Jul. 19, 2018 |
Oct. 31, 2018 |
Oct. 31, 2017 |
Jul. 31, 2017 |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Ìý
|
Ìý
|
Ìý
|
Ìý
|
Ìý
|
| Unrecognized compensation cost |
Ìý
|
Ìý
|
$ 2,440,436
|
Ìý
|
Ìý
|
| Weighted average recognition period |
Ìý
|
Ìý
|
3 years
|
Ìý
|
Ìý
|
| Stock-based compensation |
Ìý
|
Ìý
|
$ 515,291
|
Ìý
|
Ìý
|
| Share issued in exercise of stock options |
Ìý
|
Ìý
|
26,807
|
Ìý
|
Ìý
|
| Proceeds from stock options exercised |
Ìý
|
Ìý
|
$ 60,102
|
$ 53,045
|
Ìý
|
| Chief Executive Officer [Member] |
Ìý
|
Ìý
|
Ìý
|
Ìý
|
Ìý
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Ìý
|
Ìý
|
Ìý
|
Ìý
|
Ìý
|
| Options granted |
Ìý
|
200,000
|
Ìý
|
Ìý
|
Ìý
|
| Options granted, exercise price |
Ìý
|
$ 7.55
|
Ìý
|
Ìý
|
Ìý
|
| Weighted average recognition period |
Ìý
|
5 years
|
Ìý
|
Ìý
|
Ìý
|
| Chief Academic Officer [Member] |
Ìý
|
Ìý
|
Ìý
|
Ìý
|
Ìý
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Ìý
|
Ìý
|
Ìý
|
Ìý
|
Ìý
|
| Options granted |
Ìý
|
180,000
|
Ìý
|
Ìý
|
Ìý
|
| Options granted, exercise price |
Ìý
|
$ 7.55
|
Ìý
|
Ìý
|
Ìý
|
| Weighted average recognition period |
Ìý
|
5 years
|
Ìý
|
Ìý
|
Ìý
|
| Chief Operating Officer [Member] |
Ìý
|
Ìý
|
Ìý
|
Ìý
|
Ìý
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Ìý
|
Ìý
|
Ìý
|
Ìý
|
Ìý
|
| Options granted |
Ìý
|
180,000
|
Ìý
|
Ìý
|
Ìý
|
| Options granted, exercise price |
Ìý
|
$ 7.55
|
Ìý
|
Ìý
|
Ìý
|
| Weighted average recognition period |
Ìý
|
5 years
|
Ìý
|
Ìý
|
Ìý
|
| Board of directors [Member] |
Ìý
|
Ìý
|
Ìý
|
Ìý
|
Ìý
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Ìý
|
Ìý
|
Ìý
|
Ìý
|
Ìý
|
| Options granted |
Ìý
|
560,000
|
Ìý
|
Ìý
|
Ìý
|
| Weighted average recognition period |
Ìý
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