Common stock combined purchase price per share.

No definition available.

Name:	OPTT_CommonStockCombinedPurchasePricePerShare
Namespace Prefix:	OPTT_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of exercised warrants.

+ References

No definition available.

+ Details

Name:	OPTT_NumberOfExercisedWarrants
Namespace Prefix:	OPTT_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21475-112644

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

+ References

+ Details

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
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Balance Type:	na
Period Type:	instant

- 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.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Period between issuance and expiration of outstanding warrant and right embodying unconditional obligation requiring redemption by transferring asset at specified or determinable date or upon event certain to occur, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementEquityComponentsAxis=OPTT_CommonWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=OPTT_JunePurchaseAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TypeOfArrangementAxis=OPTT_SecondAmendedPurchaseAgreementMember
Namespace Prefix:
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Warrants (Details Narrative) - USD ($) $ / shares in Units, $ in Thousands	Apr. 08, 2019	Jul. 22, 2016	Jun. 02, 2016	Jul. 31, 2021	Apr. 30, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sale of Stock, Number of Shares Issued in Transaction	1,542,000
Derivative Liability, Current					$ 0
Pre-funded Warrants [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	3,385,680
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 0.01
Common Warrants [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	4,927,680
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 3.85
Warrants and Rights Outstanding, Term	5 years
June Purchase Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sale of Stock, Number of Shares Issued in Transaction			20,850
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			7,298
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right			0.35
[custom:CommonStockCombinedPurchasePricePerShare-0]			$ 92.00
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 121.60
Warrants and Rights Outstanding, Term			5 years
Number of exercised warrants				0
Second Amended Purchase Agreement [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sale of Stock, Number of Shares Issued in Transaction		29,750
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		8,925
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right		0.30
[custom:CommonStockCombinedPurchasePricePerShare-0]		$ 135.00
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 187.20
Warrants and Rights Outstanding, Term		5 years
Number of exercised warrants				0