XML 92 R80.htm IDEA: XBRL DOCUMENT v3.25.2

Basis of Accounting - Additional Information (Details) - USD ($) $ in Thousands		6 Months Ended	12 Months Ended
	Aug. 19, 2025	Dec. 31, 2025	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2023	Aug. 30, 2025	Jun. 30, 2022
Disclosure Of Reclassifications Or Changes In Presentation [Line Items]
Loss after income tax			$ 162,791	$ 220,242	$ 142,521
Net cash outflows from operating activities			158,644	161,015	120,608
Cash and cash equivalents			48,443	172,471	89,189		$ 44,631
Net current assets (liabilities)			(201,100)	124,100
Net assets (liabilities)			$ (201,069)	(75,810)
Percentage of workforce reduction			80.00%
Percentage of Board of Directors reduction			50.00%
Equity			$ (201,069)	(75,810)	(5,853)		47,977
Issued capital			497,488	466,085	320,884
Ordinary shares [member]
Disclosure Of Reclassifications Or Changes In Presentation [Line Items]
Equity			497,488	$ 466,085	$ 320,884		$ 235,277
Phase Two | Bottom of Range
Disclosure Of Reclassifications Or Changes In Presentation [Line Items]
Estimated Operating Expenses			5,000
Phase Two | Top of Range
Disclosure Of Reclassifications Or Changes In Presentation [Line Items]
Estimated Operating Expenses			$ 8,000
Events after Reporting Period
Disclosure Of Reclassifications Or Changes In Presentation [Line Items]
Cash and cash equivalents						$ 19,300
Events after Reporting Period | First Phase
Disclosure Of Reclassifications Or Changes In Presentation [Line Items]
Estimated Operating Expenses		$ 10,000
Development Funding Agreement | Change of Control
Disclosure Of Reclassifications Or Changes In Presentation [Line Items]
Percentage of repayment due to termination			0.00%
Repayment due to termination			$ 0
Development Funding Agreement | Disagreement with DFA Investors
Disclosure Of Reclassifications Or Changes In Presentation [Line Items]
Percentage of repayment due to termination			135.00%
Repayment due to termination			$ 229,500
Development Funding Agreement | Inability to Fund Development Costs
Disclosure Of Reclassifications Or Changes In Presentation [Line Items]
Percentage of repayment due to termination			150.00%
Repayment due to termination			$ 255,000
Development Funding Agreement | Safety
Disclosure Of Reclassifications Or Changes In Presentation [Line Items]
Percentage of repayment due to termination			275.00%
Repayment due to termination			$ 467,500
Development Funding Agreement | Bankruptcy and Other Material Breaches
Disclosure Of Reclassifications Or Changes In Presentation [Line Items]
Percentage of repayment due to termination			400.00%
Repayment due to termination			$ 680,000
Development Funding Agreement | Events after Reporting Period
Disclosure Of Reclassifications Or Changes In Presentation [Line Items]
Number of ordinary shares issued	136,661,003
Cash payment to DFA	$ 20,000
Percentage of share capital issued	9.99%
Development Funding Agreement | Events after Reporting Period | Ordinary shares [member]
Disclosure Of Reclassifications Or Changes In Presentation [Line Items]
Number of ordinary shares issued	136,661,003

X

- Definition

The amount of cash on hand and demand deposits, along with short-term, highly liquid investments that are readily convertible to known amounts of cash and that are subject to an insignificant risk of changes in value. [Refer: Cash; Cash equivalents]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 7
-IssueDate 2024-01-01
-Paragraph 45
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2024-en-r&anchor=para_45&doctype=Standard
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2024-01-01
-Paragraph B13
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2024-en-r&anchor=para_B13_a&doctype=Appendix&subtype=B
-URIDate 2024-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 54
-Subparagraph i
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_54_i&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_CashAndCashEquivalents
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The cash flows from (used in) operating activities, which are the principal revenue-producing activities of the entity and other activities that are not investing or financing activities, from continuing and discontinued operations. [Refer: Revenue]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 7
-IssueDate 2024-01-01
-Paragraph 10
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2024-en-r&anchor=para_10&doctype=Standard
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 7
-IssueDate 2024-01-01
-Paragraph 50
-Subparagraph d
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2024-en-r&anchor=para_50_d&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_CashFlowsFromUsedInOperatingActivities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The amount of current assets less the amount of current liabilities.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 55
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_55&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_CurrentAssetsLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

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

+ References

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfReclassificationsOrChangesInPresentationLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The amount of residual interest in the assets of the entity after deducting all its liabilities.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 1
-IssueDate 2024-01-01
-Paragraph 24
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2024-en-r&anchor=para_24_a&doctype=Standard
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 1
-IssueDate 2024-01-01
-Paragraph 32
-Subparagraph a
-Clause i
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2024-en-r&anchor=para_32_a_i&doctype=Standard
-URIDate 2024-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 13
-IssueDate 2024-01-01
-Paragraph 93
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2024-en-r&anchor=para_93_a&doctype=Standard
-URIDate 2024-03-27

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 13
-IssueDate 2024-01-01
-Paragraph 93
-Subparagraph e
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2024-en-r&anchor=para_93_e&doctype=Standard
-URIDate 2024-03-27

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 13
-IssueDate 2024-01-01
-Paragraph 93
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2024-en-r&anchor=para_93_b&doctype=Standard
-URIDate 2024-03-27

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 55
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_55&doctype=Standard
-URIDate 2024-03-27

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 78
-Subparagraph e
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_78_e&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_Equity
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

The nominal value of capital issued.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 78
-Subparagraph e
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_78_e&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_IssuedCapital
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

The amount of assets less the amount of liabilities.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 1
-IssueDate 2024-01-01
-Paragraph IG63
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2024-en-r&anchor=para_IG63&doctype=Implementation%20Guidance
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 112
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_NetAssetsLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The number of shares issued by the entity.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 106
-Subparagraph d
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_106_d&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_NumberOfSharesIssued
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The total of income less expenses from continuing and discontinued operations, excluding the components of other comprehensive income. [Refer: Other comprehensive income]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 7
-IssueDate 2024-01-01
-Paragraph 18
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2024-en-r&anchor=para_18_b&doctype=Standard
-URIDate 2024-03-27

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 1
-IssueDate 2024-01-01
-Paragraph 32
-Subparagraph a
-Clause ii
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2024-en-r&anchor=para_32_a_ii&doctype=Standard
-URIDate 2024-03-27

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 1
-IssueDate 2024-01-01
-Paragraph 24
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2024-en-r&anchor=para_24_b&doctype=Standard
-URIDate 2024-03-27

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2024-01-01
-Paragraph 28
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_28_b&doctype=Standard
-URIDate 2024-03-27

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2024-01-01
-Paragraph 23
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_23&doctype=Standard
-URIDate 2024-03-27

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 12
-IssueDate 2024-01-01
-Paragraph B10
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2024-en-r&anchor=para_B10_b&doctype=Appendix&subtype=B
-URIDate 2024-03-27

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 17
-IssueDate 2024-01-01
-Paragraph 113
-Subparagraph b
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2024-en-r&anchor=para_113_b&doctype=Standard
-URIDate 2024-03-27

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 81A
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_81A_a&doctype=Standard
-URIDate 2024-03-27

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2024-01-01
-Paragraph 106
-Subparagraph d
-Clause i
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_106_d_i&doctype=Standard
-URIDate 2024-03-27

+ Details

Name:	ifrs-full_ProfitLoss
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Cash payment to DFA.

+ References

No definition available.

+ Details

Name:	opt_CashPaymentToDFA
Namespace Prefix:	opt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Estimated operating expenses.

+ References

No definition available.

+ Details

Name:	opt_EstimatedOperatingExpenses
Namespace Prefix:	opt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Percentage of board of directors reduction.

+ References

No definition available.

+ Details

Name:	opt_PercentageOfBoardOfDirectorsReduction
Namespace Prefix:	opt_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of repayment due to termination.

+ References

No definition available.

+ Details

Name:	opt_PercentageOfRepaymentDueToTermination
Namespace Prefix:	opt_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of share capital issued.

+ References

No definition available.

+ Details

Name:	opt_PercentageOfShareCapitalIssued
Namespace Prefix:	opt_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Percentage of workforce reduction.

+ References

No definition available.

+ Details

Name:	opt_PercentageOfWorkforceReduction
Namespace Prefix:	opt_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Repayment due to termination.

+ References

No definition available.

+ Details

Name:	opt_RepaymentDueToTermination
Namespace Prefix:	opt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Details

Name:	ifrs-full_ClassesOfShareCapitalAxis=ifrs-full_OrdinarySharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CounterpartiesAxis=opt_PhaseeTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_NonadjustingEventsAfterReportingPeriodAxis=opt_EventsAfterReportingPeriodMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_CounterpartiesAxis=opt_FirstPhaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ServiceConcessionArrangementsAxis=opt_DevelopmentFundingAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ClassesOfProvisionsAxis=opt_ChangeOfControlMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ClassesOfProvisionsAxis=opt_DisagreementWithDFAInvestorsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ClassesOfProvisionsAxis=opt_InabilityToFundDevelopmentCostsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ClassesOfProvisionsAxis=opt_SafetyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_ClassesOfProvisionsAxis=opt_BankruptcyAndOtherMaterialBreachesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: