Share-Based Payments - Narrative (Details) - USD ($)	3 Months Ended
Jul. 31, 2018	Jul. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 83,000	$ 564,000
Option modification charge	7,500	56,529
Issuance of common stock for services	8,000	$ 0
Unrecognized compensation cost	$ 432,422
Period for recognition	3 years 9 months 18 days
Weighted-average grant date fair value (in usd per share)	$ 5.18	$ 1.79
Shares granted (in shares)	1,250
Grants in period, weighted average exercise price (in usd per share)	$ 7.17
Warrants outstanding (in shares)	2,004,284

The number of share warrants outstanding in connection with the financing arrangement.

No definition available.

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

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-Publisher FASB
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-Topic 718
-SubTopic 10
-Section 50
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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Fair value of share-based compensation granted to nonemployees as payment for services rendered or acknowledged claims.

+ References

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-Publisher FASB
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Gross number of share options (or share units) granted during the period.

+ References

No definition available.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ References

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- Definition

An excess of the fair value of the modified award over the fair value of the award immediately before the modification.

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- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

+ References

No definition available.

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