Aggregate offering price.

No definition available.

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- Definition

Number of additional shares that can be issued upon shareholder approval.

+ References

No definition available.

+ Details

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- Definition

Payment of sales commission.

+ References

No definition available.

+ Details

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- Definition

Percentage of outstanding common stock limit for shareholder approval.

+ References

No definition available.

+ Details

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- Definition

Sale Of Stock Consideration Received Per Transaction Remaining.

+ References

No definition available.

+ Details

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- Definition

Number of shares can be issued based upon outstanding percentage.

+ References

No definition available.

+ Details

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- Definition

Aggregate purchase of common stock.

+ References

No definition available.

+ Details

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- Definition

Face amount or stated value per share of common stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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- Definition

The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

+ References

+ Details

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- Definition

Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

+ References

+ Details

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- Definition

Amount of consideration received by subsidiary or equity investee in exchange for shares of stock issued or sold. Includes amount of cash received, fair value of noncash assets received, and fair value of liabilities assumed by the investor.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

+ References

No definition available.

+ Details

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- Definition

Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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- Details

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- Details

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Common Stock (Details Narrative) - USD ($) $ / shares in Units, $ in Millions							1 Months Ended	12 Months Ended
	Dec. 23, 2020	Nov. 20, 2020	Sep. 18, 2020	Oct. 24, 2019	Apr. 08, 2019	Jan. 07, 2019	Jan. 31, 2021	Apr. 30, 2022	Apr. 30, 2021
Common stock, shares authorized								100,000,000	100,000,000
Common stock, par value								$ 0.001	$ 0.001
Common stock, shares issued								55,905,213	52,479,051
Number of common stock shares sold					1,542,000
Alliance Global Partners [Member]
Number of common stock shares sold						12,342,506
Proceeds from issuance or sale of equity, net of issuance costs						$ 18.7
Combined purchase price per share						$ 1.51
2019 ATM Facility [Member] \| Alliance Global Partners [Member]
Aggregate offering price						$ 25.0
Number of common stock shares sold						17,595,472
Proceeds from issuance or sale of equity, net of issuance costs						$ 23.4
Combined purchase price per share						$ 1.33
Payment of sales commission						$ 0.8
2020 ATM Facility [Member]
Proceeds from issuance or sale of equity, net of issuance costs								$ 75.0
Payment of sales commission								25.0
2020 ATM Facility [Member] \| Alliance Global Partners [Member]
Aggregate offering price		$ 50.0						$ 50.0
Number of common stock shares sold		17,179,883						17,179,883
Proceeds from issuance or sale of equity, net of issuance costs								$ 50.0
Combined purchase price per share								$ 2.91	$ 2.91
Payment of sales commission								$ 1.6
2020 ATM Facility [Member] \| Alliance Global Partners [Member] \| Maximum [Member]
Aggregate purchase of common stock		$ 100.0
Common Stock Purchase Agreement [Member] \| Aspire Capital Fund, LLC [Member]
Number of common stock shares sold			6,424,205				3,722,251	5,025,000
Proceeds from issuance or sale of equity, net of issuance costs			$ 4.0				$ 11.8	$ 2.9
Combined purchase price per share			$ 0.63				$ 3.17	$ 0.57
Aggregate purchase of common stock			$ 12.5
[custom:PercentageOfOutstandingCommonStockLimitForShareholderApproval]	19.99%		19.99%
[custom:StockIssuedDuringPeriodSharesCanBeIssuedBasedUponOutstandingPercentage]			3,722,251
[custom:NumberOfAdditionalSharesThatCanBeIssuedUponShareholderApproval]	9,864,706
[custom:SaleOfStockConsiderationReceivedPerTransactionRemaining]								$ 1.0
Common Stock Purchase Agreement [Member] \| Aspire Capital Fund, LLC [Member] \| Maximum [Member]
Aggregate purchase of common stock				$ 10.0