Opthea Limited (OPT) 20-F 28 Oct 21 2021 FY Annual report (foreign) Financial data

Document and Entity Information

Document and Entity Information	12 Months Ended
	Jun. 30, 2021shares
Document Information [Line Items]
Document Type	20-F
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Registrant Name	OPTHEA LIMITED
Entity Central Index Key	0001815620
Current Fiscal Year End Date	--06-30
Entity File Number	001-39621
Entity Incorporation, State or Country Code	C3
Entity Address, Address Line One	Level 4
Entity Address, Address Line Two	650 Chapel Street
Entity Address, City or Town	South Yarra
Entity Address, Postal Zip Code	3141
Document Annual Report	true
Document Transition Report	false
Document Registration Statement	false
Document Shell Company Report	false
ICFR Auditor Attestation Flag	false
Document Accounting Standard	International Financial Reporting Standards
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Interactive Data Current	Yes
Entity Address, Country	AU
Business Contact
Document Information [Line Items]
Entity Address, Address Line One	Corporation Service Company
Entity Address, Address Line Two	1180 Avenue of the Americas
Entity Address, City or Town	New York
Entity Address, Postal Zip Code	10036
City Area Code	+61 3
Local Phone Number	9826 0399
Contact Personnel Name	Dr Megan Baldwin
Contact Personnel Email Address	info@opthea.com
Entity Address, Address Line Three	Suite 210
Entity Address, State or Province	NY
Ordinary Shares
Document Information [Line Items]
No Trading Symbol Flag	true
Title of 12(b) Security	Ordinary shares, no par value
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding	351,003,541
American Depositary Shares
Document Information [Line Items]
Trading Symbol	OPT
Title of 12(b) Security	American Depositary Shares, each representing eight ordinary shares
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding	12,717,119

Consolidated Statement of Profi

Consolidated Statement of Profit or Loss and Other Comprehensive Income - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Abstract]
Revenue	$ 68,613	$ 59,061	$ 112,497
Other income	398,951	522,082	598,269
Research and development	(25,891,851)	(12,064,008)	(22,419,712)
Patent expenses	(137,666)	(282,042)	(194,512)
Intellectual property expenses	(291,235)	(74,938)
Administration expenses	(13,399,748)	(4,702,860)	(3,686,621)
Occupancy expenses	(18,445)	(23,272)	(78,115)
Net foreign exchange gain/(loss)	(11,011,961)	(265,989)	241,814
Loss before income tax	(50,283,342)	(16,831,966)	(25,426,380)
Income tax benefit	4,938,846	5,708,767	10,474,432
Loss for the year	(45,344,496)	(11,123,199)	(14,951,948)
Items that will not be reclassified subsequently to profit or loss:
Fair value gains on investments in financial assets	469,767	41,098	181,687
Other comprehensive income for the period, net of tax	469,767	41,098	181,687
Total comprehensive loss for the year	(44,874,729)	(11,082,101)	(14,770,261)
Loss for the year is attributable to:
Owners of the Company	(45,344,496)	(11,123,199)	(14,951,948)
Loss for the year	(45,344,496)	(11,123,199)	(14,951,948)
Total comprehensive loss for the year is attributable to:
Owners of the Company	(44,874,729)	(11,082,101)	(14,770,261)
Total comprehensive loss for the year	$ (44,874,729)	$ (11,082,101)	$ (14,770,261)
Loss per share attributable to the owners of the Company:
- Basic and diluted loss per share (cents)	$ (14.15)	$ (4.27)	$ (6.42)

Consolidated Statement of Finan

Consolidated Statement of Financial Position - USD ($)	Jun. 30, 2021	Jun. 30, 2020	Jul. 01, 2019
Current assets:
Cash and cash equivalents	$ 118,193,177	$ 42,650,858	$ 15,121,820
Current tax receivable	4,972,898	5,868,152	10,278,082
Receivables	565,286	195,573	207,701
Prepayments	14,386,155	329,151	298,156
Total current assets	138,117,516	49,043,734	25,905,759
Non-current assets:
Investment in financial assets		199,417	501,454
Property and equipment, net	23,259	25,568	37,963
Right-of-use assets	93,852	167,460
Prepayments	174,541
Total non-current assets	291,652	392,445	539,417
Total assets	138,409,168	49,436,179	26,445,176
Current liabilities:
Payables	2,501,518	4,053,961	4,179,453
Lease liabilities	112,965	99,745
Other financial liabilities		163,548	17,971
Provisions	492,002	440,765	378,168
Total current liabilities	3,106,485	4,758,019	4,575,592
Non-current liabilities:
Lease liabilities		82,545
Provisions	16,915	27,643	17,445
Total non-current liabilities	16,915	110,188	17,445
Total liabilities	3,123,400	4,868,207	4,593,037
Net Assets	135,285,768	44,567,972	21,852,139
Equity
Contributed equity	234,147,526	113,852,364	80,331,016
Accumulated Loss	(124,123,982)	(78,779,486)	(67,656,287)
Reserves	25,262,224	9,495,094	9,177,410
Total Equity	$ 135,285,768	$ 44,567,972	$ 21,852,139

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($)	Total	Contributed Equity	Pre-funded Warrants	Option Reserve	Share-based Payment Reserve	Fair Value of Investment Reserve	FX Translation Reserve	Accumulated Deficit
Beginning balance at Jun. 30, 2018	$ 28,258,085	$ 69,788,130		$ 1,473,302	$ 1,816,817	$ 353,604	$ 7,530,571	$ (52,704,339)
Fair value gains on investments in financial assets						181,687
Net loss for the year	(14,951,948)					(14,951,948)		(14,951,948)
Total comprehensive income and expense for the period	(14,770,261)					181,687		(14,951,948)
Issuance of ordinary shares	9,069,584	9,069,584
Exercise of options granted under LTIP and NED plan		1,473,302		$ (1,473,302)
Exchange on conversion	(1,390,678)				(100,457)	(17,591)	(1,272,630)
Recognition of share-based payment expense	685,409				685,409
Ending balance at Jun. 30, 2019	21,852,139	80,331,016			2,401,769	517,700	6,257,941	(67,656,287)
Fair value gains on investments in financial assets	41,098					41,098
Net loss for the year	(11,123,199)					(11,123,199)		(11,123,199)
Total comprehensive income and expense for the period	(11,082,101)					41,098		(11,123,199)
Issuance of ordinary shares	33,236,520	33,236,520
Exercise of options granted under LTIP and NED plan		284,828			(284,828)
Exchange on conversion	(171,274)				266,451	(7,389)	(430,336)
Recognition of share-based payment expense	732,688				732,688
Ending balance at Jun. 30, 2020	44,567,972	113,852,364			3,116,080	551,409	5,827,605	(78,779,486)
Fair value gains on investments in financial assets	469,767					469,767
Net loss for the year	(45,344,496)					(45,344,496)		(45,344,496)
Total comprehensive income and expense for the period	(44,874,729)					469,767		(45,344,496)
Issuance of ordinary shares and pre-funded warrants on NASDAQ listing net of issuance cost $10,126,959	117,023,620	105,477,591	$ 11,546,029
Issuance of ordinary shares on exercise of pre-funded warrants net of issuance costs $1,099,412		11,546,029	$ (11,546,029)
Exercise of options granted under LTIP and NED plan		3,271,542			(3,271,542)
Exchange on conversion	14,671,267				345,474	64,235	14,261,558
Recognition of share-based payment expense	3,897,638				3,897,638
Ending balance at Jun. 30, 2021	$ 135,285,768	$ 234,147,526			$ 4,087,650	$ 1,085,411	$ 20,089,163	$ (124,123,982)

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical)	12 Months Ended
	Jun. 30, 2021USD ($)
Ordinary Shares
Issuance of ordinary shares and pre-funded warrants, net of issuance cost	$ 10,126,959
Pre-funded Warrants
Issuance of ordinary shares and pre-funded warrants, net of issuance cost	1,099,412
Exercise of Warrants
Issuance of ordinary shares and pre-funded warrants, net of issuance cost	$ 1,099,412

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Cashflow from operating activities
Interest received	$ 390,128	$ 496,159	$ 590,548
Royalty and license income received	103,031	96,189	122,631
Grant Income	26,949	41,629	57,235
Payment of lease interest	(5,782)	(5,147)
Payments to suppliers, employees and for research & development and intellectual property costs (inclusive of GST)	(51,894,593)	(16,437,147)	(26,910,026)
Research and development tax incentive scheme credit received	5,834,100	10,118,697	9,097,525
Net cash flows used in operating activities	(45,546,167)	(5,689,620)	(17,042,087)
Cash flow from investing activities:
Purchase of plant and equipment	(12,702)	(2,531)	(10,398)
Proceeds from sale of financial assets	669,184	335,746	250,241
Net cash used in investing activities	656,482	333,215	239,843
Cash flows from financing activities:
Payment of lease liabilities	(87,373)	(66,781)
Net proceeds on issue of shares	105,477,591	32,951,692	9,069,584
Net proceeds on issuance of pre-funded warrants	11,546,029
Cash received for ordinary shares issued on exercise of options		284,828
Net cash provided by financing activities	116,936,247	33,169,739	9,069,584
Increase in cash and cash equivalents	72,046,562	27,813,334	(7,732,660)
Effects of exchange rate changes on the balance of cash held in foreign currencies	3,495,757	(284,296)	(1,225,847)
Cash and cash equivalents at beginning of period	42,650,858	15,121,820	24,080,327
Cash and cash equivalents at end of period	$ 118,193,177	$ 42,650,858	$ 15,121,820

Reporting Entity

Reporting Entity	12 Months Ended
	Jun. 30, 2021
Reporting Entity [Abstract]
Reporting Entity	Note 1 Reporting Entity Opthea Limited (the Company) is a listed public company incorporated in Australia. The address of its registered office and principal place of business is: Suite 0403, Level 4, 650 Chapel Street, South Yarra, VIC 3141, Australia. These consolidated financial statements comprise the Company and its subsidiaries (together referred to as the Group). The Group’s principal activity is the development of new drugs for the treatment of eye diseases.

Basis of Accounting

Basis of Accounting	12 Months Ended
	Jun. 30, 2021
Basis Of Accounting [Abstract]
Basis of Accounting	Note 2. Basis of Accounting These financial statements are general purpose financial statements which have been prepared in accordance with International Financial Reporting Standards (“or IFRS”) as issued by the International Accounting Standards Board (the “IASB”). The financial statements comprise the consolidated financial statements of the Group. For the purposes of preparing the consolidated financial statements, the Company is a for‑profit entity. The financial statements were authorized for issue by the directors on October 28, 2021.

Summary of Accounting Policies

Summary of Accounting Policies	12 Months Ended
	Jun. 30, 2021
Description Of Business And Summary Of Significant Accounting Policies [Abstract]
Summary of Accounting Policies	Note 3. Summary of Accounting Policies The consolidated financial statements have been prepared using the significant accounting policies and measurement bases summarized below. Basis of measurement The consolidated financial statements have been prepared on a historical cost basis, except for the investments classified as financial assets, which have been measured at fair value. All amounts are presented in United States dollars unless otherwise stated. Change in presentation and functional currencies Functional currency An entity’s functional currency is the currency of the primary economic environment in which the entity operates. During the current year, the Group’s operations have continued to move further towards being US$ denominated and several other factors during the period have also contributed to the Group changing its functional currency during the year, such as the completion of U.S. initial public offering (IPO) and the Nasdaq listing in October 2020, opening a US subsidiary in May 2021 for a planned expansion into the US, and expanding the Board of Directors with the appointment of four US based Directors. A significant element in the Group’s assessment to change the functional currency resulted from the significant increase in expenses denominated in US dollars relating to advanced clinical trials since the commencement of Phase 3 trials in March 2021. These changes, as well as the fact that the Group’s principal source of financing is now the U.S. capital market and all of the Group’s budgeting and planning is conducted solely in dollars led to the Company determining that the U.S. dollar (US$) best represents the currency of the primary economic environment in which the entity now operates. Accordingly, the Group changed its functional currency from Australian dollar (A$) to U.S. dollar (US$) effective January 1, 2021. The change in functional currency has been applied prospectively with effect from January 1, 2021 in accordance with the requirements of the Accounting Standards. To give effect in functional currency, the assets and liabilities of the Group were converted into U.S. dollars at a fixed exchange rate of US$1: A$1.2973. Presentation Currency Following the change in functional currency, the Group changed its presentation currency from Australian dollars (A$) to US$. The change in presentation currency was made to better reflect the Group’s business activities and to enhance access to U.S. capital markets. Prior to the change, the Group reported its financial statements in Australian dollars (A$). A change in presentation currency is a change in accounting policy which is accounted for retrospectively, including the restatement of 2019 Balance Sheet. In making this change in presentation currency, the Group followed the requirements set out in IAS 21 The Effects of Changes in Foreign Exchange Rates Basis of consolidation The consolidated financial statements incorporate the financial statements of the Company and its subsidiaries. Control is achieved when the Company: • Has power over the investee; • Is exposed, or has rights, to variable returns from its involvement with the investee; and • Has the ability to use its power to affect its returns. Consolidation of a subsidiary begins when the Company obtains control over the subsidiary and ceases when the Company loses control of the subsidiary. All intragroup assets and liabilities, equity, income, expenses and cash flows relating to transactions between members of the Group are eliminated in full on consolidation. Foreign currency translation i. Functional and presentation currency As of January 1, 2021 the Group determined that its functional and presentation currency had changed from Australian Dollars to United States Dollars. Therefore, the functional and presentation currency of the Group is the United States dollars (US$). The prior year financial information has been restated to United States dollars. ii. Transactions and balances Transactions in foreign currencies are initially recorded in the functional currency by applying the exchange rates ruling in place at the date of the transaction. Monetary assets and liabilities denominated in foreign currencies are retranslated at the rate of exchange ruling in place at the reporting date. Non‑monetary items that are measured in terms of historical cost in a foreign currency are translated using the exchange rate as of the date of the initial transaction. Non‑monetary items measured at fair value in a foreign currency are translated using the exchange rates at the date when the fair value was determined. Financial assets and liabilities Recognition and derecognition of financial assets Purchases and sales of financial assets that require delivery of assets within the time frame generally established by regulation or convention in the marketplace are recognized on the trade date, i.e., the date that the Group commits to purchase the asset. Financial assets are derecognized when the right to receive cash flows from the financial assets has expired or when the entity transfers substantially all the risks and rewards of the financial assets. If the entity neither retains nor transfers substantially all of the risks and rewards, it derecognizes the asset if it has transferred control of the assets. When financial assets are recognized initially, they are measured at fair value, plus directly attributable transaction costs. Cash and cash equivalents Cash and cash equivalents in the statement of financial position comprise cash at bank and in hand and short‑term deposits with an original maturity of three months or less that are readily convertible to known amounts of cash and which are subject to an insignificant risk of changes in value. For the purposes of the statement of cash flows, cash and cash equivalents consist of cash and cash equivalents as defined above. Other receivables Other receivables generally comprise bank interest receivable, other receivables from external parties and Goods and Services Tax (GST) credits receivable and are recognized and carried at original invoice amount less an allowance for any uncollectible amounts. The amounts are usually received within 30 to 60 days of recognition. The Group measures the loss allowance for receivables at an amount equal to lifetime expected credit losses (ECL). The ECL on receivables are estimated under the simplified approach as permitted under IFRS 9 “Financial Instruments.” This uses a provision matrix by reference to past experience of the debtor and an analysis of the debtor’s current financial position, adjusted for factors that are specific to the debtors and general economic conditions of the industry in which the debtors operate. The Group writes off a receivable when there is information indicating that the debtor is in severe financial difficulty and there is no realistic prospect of recovery. Investments Investments in financial assets comprise of the Group’s non‑current investments in listed companies. On initial recognition, the Group may make an irrevocable election (on an instrument‑by‑instrument basis) to designate investments in equity instruments as fair value through other comprehensive income (FVTOCI). Designation at FVTOCI is not permitted if the equity instrument is held for trading. Investments in equity instruments at FVTOCI are initially measured at fair value plus transaction costs. Subsequently, they are measured at fair value with gains or losses arising from changes in the fair value recognized in other comprehensive income and accumulated in the fair value of investments reserve. The fair values of investments in financial assets that are actively traded in organized financial markets is determined by reference to quoted market bid prices at the close of business on the reporting date. The cumulative gain or loss is not reclassified to profit or loss on disposal of the equity instruments. Dividends on these investments in equity instruments are recognized in profit or loss in accordance with International Financial Reporting Standards. Finance income Almost all of the Group’s finance income is earned on short‑term bank deposits, and as such, finance income is recognized when the Group’s right to receive the payment is established. Payables Payables are carried at amortized cost and due to their short‑term nature, they are not discounted. They represent liabilities for goods and services provided to the Group prior to the end of the financial year that are unpaid and arise when the Group becomes obliged to make future payments in respect of the purchase of these goods and services. The amounts are unsecured and are usually paid within 30 days of recognition. Other financial liabilities Other financial liabilities in the consolidated statement of financial position represent the year end marked‑to‑market value of forward rate foreign exchange contracts to purchase US dollars (Contracts) which were entered into prior to the change in functional currency which took place on January 1, 2021. These Contracts were used to settle US dollar denominated payables and expired within one year. The foreign exchange loss on recognition of the Contracts was included in ‘net foreign exchange gain/(loss)’ in the consolidated statement of profit or loss and other comprehensive income. Plant and equipment Plant and equipment are stated at historical cost less accumulated depreciation and any accumulated impairment losses. Depreciation is calculated on a straight‑line basis over their useful economic lives as follows: • Equipment and furniture – 3 to 10 years; and • Leasehold improvements – 8 years or the term of the lease if shorter. The assets’ residual values, useful lives and amortization methods are reviewed, and adjusted if appropriate, at each financial year end. An item of plant and equipment is derecognized upon disposal or when no further economic benefits are expected from its use or disposal. Leases The Group assesses at contract inception whether a contract is, or contains, a lease. A contract is, or contains, a lease if the contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. The Group applies a single recognition and measurement approach for all leases, except for short‑term leases and leases of low‑value assets. The Group recognizes lease liabilities to make lease payments and right‑of‑use assets representing the right to use the underlying assets. Right‑of‑use assets Right‑of‑use assets are recognized at the commencement date of the lease (that is the date the underlying asset is available for use). Right‑of‑use assets are measured at cost, less any accumulated depreciation and any impairment losses, and adjusted for any remeasurement of lease liabilities. The cost of right‑of‑use assets include the amount of lease liabilities recognized, initial direct costs incurred, and lease payments made at or before the commencement date less any lease incentives received. Right‑of‑use assets are depreciated on a straight‑line basis over the shorter of the lease terms and the estimated useful lives of the assets. Lease liabilities Lease liabilities are recognized at the commencement date of the lease at the present value of lease payments to be made over the lease term. The lease payments include fixed payments (including in‑substance fixed payments) less any lease incentives receivable. In calculating the present value of lease payments, the Group uses its incremental borrowing rate at the lease commencement date because the interest rate implicit in the lease is not readily determinable. The incremental borrowing rate is determined using market yields on bonds with similar terms to maturity. After the commencement date, the amount of lease liabilities is increased to reflect the accretion of interest and reduced for the lease payments made. In addition, the carrying amount of lease liabilities is remeasured if there is a modification, a change in the lease term, a change in lease payments (e.g., a change to future lease payments resulting from a change in an index or rate). Leases of low‑value assets For short‑term leases (lease term of 12 months or less) and leases of low‑value assets (such as photo copiers and telephones), the Group has opted to recognize a lease expense on a straight‑line basis as permitted by IFRS 16. This expense is presented within “administrative expenses” in the consolidated statement of profit or loss and other comprehensive income. Research and development costs Research costs are expensed as incurred. An intangible asset arising from the development expenditure on an internal project will only be recognized when the Group can demonstrate the technical feasibility of completing the intangible asset so that it will be available for use or sale, its intention to complete and its ability to use or sell the asset, how the asset will generate future economic benefits, the availability of resources to complete the development and the ability to measure reliably the expenditure attributable to the intangible asset during its development. As of June 30, 2021, 2020 and 2019, the Group is in the research phase and has not capitalized any development costs to date. Provisions and employee benefits i. Wages, salaries, annual leave and sick leave Liabilities for wages and salaries, including non‑monetary benefits and annual leave expected to be settled within 12 months of the reporting date are recognized in current provisions in respect of employees’ services up to the reporting date. They are measured at the amounts expected to be paid when the liabilities are settled. Expenses for non‑accumulating sick leave are recognized when the leave is taken and are measured at the rate paid or payable. ii. Long service leave The liability for long service leave is recognized in the provision for employee benefits and measured as the present value of expected future payments to be made in respect of services provided by employees up to the reporting date. Consideration is given to expected future wage and salary levels, experience of employee departures, and periods of service. Expected future payments are discounted using market yields at the reporting date on bonds with terms to maturity that match, as closely as possible, the estimated future cash outflows. Share‑based payment transactions The Group provides benefits to directors and employees (including key management personnel) of the Group in the form of share‑based payments, whereby employees render services in exchange for shares or rights over shares (equity‑settled transactions). The cost of these equity‑settled transactions with employees is measured by reference to the fair value at the date at which they are granted. Binomial models are used to value the options issued. The cost of the equity‑settled transactions is recognized, together with a corresponding increase in equity, over the period in which the performance conditions are fulfilled (the vesting period), ending on the date on which the relevant employees become fully entitled to the award (the vesting date). The charge to profit or loss for the period is the cumulative amount less the amounts already charged in previous periods. There is a corresponding credit to equity. Until an award has vested, any amounts recorded are contingent and will be adjusted if more or fewer awards vest than were originally anticipated to do so. Contributed equity Ordinary shares are classified as equity. Incremental costs directly attributable to the issue of new shares or options are shown in equity as a deduction, net of tax, from the proceeds. Revenue recognition License revenue in connection with licensing of the Group’s intellectual property (including patents) to customers is recognized as a right to use the Group’s intellectual property as it exists at the point in time in which the license is granted. This is because the contracts for the license of intellectual property are distinct and do not require, nor does the customer reasonably expect, that the Group will undertake further activities that significantly affect the intellectual property to which the customer has the rights. Although the Group is entitled to sales‑based royalties from the eventual sales of goods and services to third parties using the intellectual property licensed, these royalty arrangements do not in themselves indicate that the customer would reasonably expect the Group to undertake such activities, and no such activities are undertaken or contracted in practice. Accordingly, the promise to provide rights to the Group’s intellectual property is accounted for as a performance obligation satisfied at a point in time. The following consideration is received in exchange for licenses of intellectual property: • Up‑front license fees – these are fixed amounts and are recognized at the point in time when the Group transfers the intellectual property to the customer. • Sales‑based royalties – these are variable consideration amounts promised in exchange for the license of intellectual property and are recognized when the sales to third parties occur given the performance obligation to transfer the intellectual property to the customer is already satisfied. During the years ended June 30, 2021, 2020 and 2019, the Group’s only revenue related to sales‑based royalties. Income tax Current tax Current tax assets and liabilities for the current and prior periods are measured at the amount expected to be recovered from or paid to the taxation authorities based on the current period’s taxable income. The tax rates and tax laws used to compute the amount are those that are enacted or substantively enacted by the reporting date. Research and development tax incentive The Research and Development (R&D) Tax Incentive Scheme is an Australian Federal Government program under which eligible companies with annual aggregated revenue of less than A$20 million can receive cash amounts equal to 43.5% of eligible research and development expenditures from the Australian Taxation Office (ATO). The R&D Tax Incentive Scheme incentive relates to eligible expenditure incurred in Australia and, under certain circumstances, overseas on the development of the Group’s lead candidate, OPT‑302. The R&D tax incentive is applied annually to eligible expenditure incurred during the Group’s financial year following annual application to AusIndustry, an Australian governmental agency, and subsequent filing of its Income Tax Return with the ATO after the financial year end. The Group estimates the amount of R&D tax incentive after the completion of the financial year based on eligible Australia and overseas expenditures incurred during that year. The Group has presented incentives in respect of the R&D Tax Incentive Scheme within income tax benefit in the Statement of Profit or Loss and Other Comprehensive Income by analogizing with IAS 12 “Income Taxes”. Deferred tax Deferred income tax is provided on all temporary differences at the reporting date between the tax bases of assets and liabilities and their carrying amounts for financial reporting purposes. Deferred income tax liabilities are recognized for all taxable temporary differences except when the deferred income tax liability arises from the initial recognition of goodwill or of an asset or liability in a transaction that is not a business combination and that, at the time of the transaction, affects neither the accounting profit nor taxable profit or loss. Deferred income tax assets are recognized for all deductible temporary differences, carry forward of unused tax assets (or credits) and unused tax losses, to the extent that it is probable that taxable profit will be available against which the deductible temporary differences, and the carry forward of unused tax credits and unused tax losses can be utilized, except when the deferred income tax asset relating to the deductible temporary differences arises from the initial recognition of an asset or liability in a transaction that is not a business combination and, at the time of the transaction, affects neither the accounting profit or taxable profit or loss. The carrying amount of deferred income tax assets is reviewed at each reporting date and reduced to the extent that it is no longer probable that sufficient taxable profit will be available to allow all or part of the deferred income tax asset to be utilized. Unrecognized deferred income tax assets are reassessed at each reporting date and are recognized to the extent that it has become probable that future taxable profit will allow the deferred tax asset to be recovered. Deferred income tax assets and liabilities are measured at the tax rates that are expected to apply to the year when the asset is realized or the liability is settled, based on tax rates (and tax laws) that have been enacted or substantively enacted at balance date. Income taxes relating to items recognized directly in equity are recognized directly in equity and not in profit or loss. Tax consolidation legislation Tax consolidation is a system adopted by the ATO that treats a group of entities as a single entity for tax purposes. Opthea Limited and its 100% owned Australian domiciled subsidiary formed a tax consolidated group effective July 1, 2003. The head entity, Opthea Limited, and its controlled entity, Vegenics Pty Ltd, are current members of the tax consolidated group and account for their own current and deferred tax amounts. Members of the tax consolidated group have adopted the “separate taxpayer within group” method to allocate the current and deferred tax amounts to each entity within the Group. This method requires adjustments for transactions and events occurring within the tax consolidated group that do not give rise to a tax consequence for the Group or that have a different tax consequence at the level of the Group. Other taxes Revenues, expenses, assets and liabilities are recognized net of the amount of GST except: • When the GST incurred on a purchase of goods and services is not recoverable from the taxation authority, in which case the GST is recognized as part of the cost of acquisition of the asset or as part of the expense item as applicable; and • Receivables and payables are stated with the amount of GST included. The net amount of GST recoverable from, or payable to the taxation authority is included as part of receivables or payables in the statement of financial position. Cash flows are included in the statement of cash flows on a gross basis and the GST component of cash flows arising from investing and financing activities, which is recoverable from, or payable to, the taxation authority is classified as part of operating cash flows. Commitments and contingencies are disclosed net of the amount of GST recoverable from, or payable to, the taxation authority.

Critical Accounting Judgements

Critical Accounting Judgements and Key Sources of Estimation Uncertainty	12 Months Ended
	Jun. 30, 2021
Disclosure Of Changes In Accounting Estimates [Abstract]
Critical Accounting Judgements and Key Sources of Estimation Uncertainty	Note 4. Critical Accounting Judgements and Key Sources of Estimation Uncertainty In applying the Group’s accounting policies, management continually evaluates judgments, estimates and assumptions based on experience and other factors, including expectations of future events that may have an impact on the Group. All judgments, estimates and assumptions made are believed to be reasonable based on the most current set of circumstances available to management. Actual results may differ from the judgments, estimates and assumptions. Significant judgments, estimates and assumptions made by management in the preparation of these financial statements are outlined below: 4.1 Critical judgments in applying accounting policies Research and development costs The majority of Opthea’s expenditure is incurred as a result of clinical trials for OPT‑302. During the years ended June 30, 2019 2020 and 2021, Opthea progressed Phase 2b wet age‑related macular degeneration (wet AMD) and Phase 1b/2a diabetic macular edema (DME) trials. Phase 3 clinical trials for OPT-302 was initiated during 2021. A key measure of Opthea’s performance is the level of expenditure incurred on the research of OPT‑302 . Judgment is required in relation to: • The classification of expenses in the income statement between research and development costs and operating expenses; and • Whether costs relate to R&D, and consequently if they meet the capitalization criteria under AASB 138 “Intangible Assets.” The directors have determined that the Group is still in a research phase and accordingly, no development costs have been capitalized as of June 30, 2021, 2020 and 2019. Taxation Research and development tax incentive The Research and Development (R&D) Tax Incentive Scheme is an Australian Federal Government program under which eligible companies can receive cash refunds of 43.5% of eligible R&D expenditure. Judgments are required as to the R&D tax incentive refundable offset eligibility in respect of: • The Group’s ability to make claims and its continued compliance under the scheme; • R&D and other supporting costs previously approved by Australian tax authorities; • Estimated amounts, timing and geographical location of future costs related to the projects for which applications have been approved to date; and • Assessment of whether expenditure on projects for which approval has been given by Australian tax authorities relate to Australian or overseas expenditure. For the years ended June 30, 2021, 2020 and 2019, the Group has recognized an R&D tax incentive receivable of US$5.0 million and US$5.9 million respectively within the consolidated statement of financial position, with a corresponding amount recognized within income tax benefit within the consolidated statement of profit or loss and other comprehensive income. The R&D tax incentive receivable as of June 30, 2021 and 2020 is based on the legislation as currently enacted as of June 30, 2021 and 2020, respectively. Any proposed changes to the legislation, such as rate changes to the eligibility requirements, may have a retrospective impact if the legislation is passed, currently no such legislative changes have occurred. Investment tax credits such as the R&D tax incentive are outside of the scope of IAS 12 “ Income Taxes Accounting for Government Grants and Disclosure of Government Assistance • The R&D tax incentive is considered an income tax offset which will be offset against the Group’s tax obligation if and when the Group returns to a net tax payable position. In addition, whilst the Group is currently eligible to receive cash payments under the scheme since its consolidated revenue is currently below A$20 million, if and when the Group generates revenue in excess of A$20 million the R&D tax incentive will become non‑refundable and can only be offset against any future income tax payable by the Group. • The ATO, which is the tax authority in Australia, manages the annual claims process as the R&D tax incentive is included in the Group’s annual income tax return. • The ATO is also responsible for making the R&D tax incentive cash payment if a company is eligible for a cash refund under the program, oversees compliance with the requirements of the R&D tax incentive scheme and performs pre‑issuance reviews. Income tax The Group’s accounting policy for taxation requires judgments as to the differences between tax and accounting treatments of income and costs recognized in the consolidated statement of profit or loss and other comprehensive income. Judgment is also required in assessing whether deferred tax assets and liabilities are recognized in the statement of financial position and if accumulated income tax losses can be used to offset potential future tax profits. Functional currency Effective January 1, 2021 the Group’s functional and presentation currency changed from Australian dollars to U.S. dollars as disclosed in Note 3. The Group’s assets, liabilities and equity which were previously denominated in Australian dollars were translated into U.S. dollars on the date the functional currency changed. Significant judgment is required in determining the currency of the primary economic environment in which the Group operates, which requires an evaluation of various indicators related to the Group’s underlying transactions, events and conditions as they relate to generating and expending cash. 4.2 Key sources of estimation uncertainty Share‑based payment transactions The Group measures the cost of equity‑settled transactions with employees by reference to the fair value of the equity instruments at the date at which they are granted. Fair values are determined internally using Binomial models. The related assumptions are detailed in note 31. The accounting estimates and assumptions relating to equity‑settled share‑based payments have no impact on the carrying amounts of assets and liabilities in future reporting periods but may impact expenses and equity. Should one or more of the assumptions and estimates used in estimating the fair value of share ‑based payments change, this could have a material impact on the amounts recognized in equity and employee ‑related expenses .

Application of New and Revised

Application of New and Revised Accounting Standards	12 Months Ended
	Jun. 30, 2021
Description Of Expected Impact Of Initial Application Of New Standards Or Interpretations [Abstract]
Application of New and Revised Accounting Standards	Note 5. Application of New and Revised Accounting Standards New and amended Accounting Standards that are effective for the current year The Group has adopted all of the new and revised Standards and Interpretations issued by the International Accounting Standards Board (the IASB) that are relevant to its operations and effective for the current year. New and revised Standards and amendments thereof and Interpretations effective for the current year that are relevant to the Group include: • International Financial Reporting Standard Definition of Material (Amendments to IAS 1 and IAS ‑8) • International Financial Reporting Standard Amendments to Conceptual Framework (IAS 1 and IAS 8) In the current year, the Group has applied a number of amendments to International Financial Reporting Standards and Interpretations issued by the International Accounting Standards Board (IASB) that are effective for an annual period that begins on or after July 1, 2020. Their adoption has not had any material impact on the disclosures or on the amounts reported in these financial statements. New and revised International Accounting Standards and Interpretations on issue but not yet effective At the date of authorization of the financial statements, the Group has not applied the following new and revised International Accounting Standards, Interpretations and amendments that have been issued but are not yet effective: Standard/amendments Effective for annual reporting periods beginning on or after IFRS 1, IAS 12 – Deferred Tax related to Assets and Liabilities arising from a Single Transaction January 1,2023 IAS 8 – Disclosure of Accounting Policies and Definition of Accounting Estimates January 1,2023 IFRS 10 and IAS 28 – Effective Date of Amendments to and – Effective Date of Amendments to and and Editorial Corrections January 1,2023 (Editorial correction apply from January 1, 2018) IAS 1 – Classification of Liabilities as Current or Non-Current January 1,2023 IAS 1 – Classification of Liabilities as Current or Non-Current – Deferral of Effective Date January 1,2023 IFRS 16, IFRS 9, IFRS 1 and IAS 41 – Annual Improvements 2018-2020 and Other Amendments January 1,2023 IFRS 16 Related Rent Concessions beyond 30 June 2021 Amendment to IFRS16 June 1, 2021 The new and revised Accounting Standards, Interpretations and amendments listed above are not expected to have a material impact on the amounts recognized or disclosures included in the Group’s financial statements.

Segment Information

Segment Information	12 Months Ended
	Jun. 30, 2021
Disclosure Of Operating Segments [Abstract]
Segment Information	Note 6. Segment Information The Group operates in one industry and one geographical area, those being the biotechnology and healthcare industry and Australia (as the U.S subsidiary was only incorporated in May 2021 and currently has no transactions or contracts with customers), respectively. The Group is focused primarily on developing a novel therapy for the treatment of highly prevalent and progressive retinal diseases. The chief executive officer regularly reviews entity wide information that is compliant with International Financial Reporting Standards. There is only one segment for segment reporting purposes, and the information reviewed by the chief executive officer for the purpose of resources allocation and performance assessment is the same as the information presented in the consolidated financial statements. The Group’s only revenue stream in the current and previous financial year is royalty income generated from licenses granted in respect of the Group’s intellectual property that are unrelated to the Group’s core business and the development of OPT‑302 and that are not under development. These licenses are primarily used by third‑party licensees for research purposes. All of the royalty income of US$68,613 (2020: US$59,061 2019:US$112,497) was generated from customers based outside of Australia. The Group does not have any major customers. All property, plant and equipment are located in Australia .

Revenue

Revenue	12 Months Ended
	Jun. 30, 2021
Revenue [Abstract]
Revenue	Note 7. Revenue 2021 2020 2019 Restated Restated US$ US$ US$ Revenue 68,613 59,061 112,497 Total Revenue 68,613 59,061 112,497

Other Income

Other Income	12 Months Ended
	Jun. 30, 2021
Analysis Of Income And Expense [Abstract]
Other Income	Note 8. Other Income 2021 2020 2019 Restated Restated US$ US$ US$ Finance Income 372,002 480,453 541,034 Grant Income 26,949 41,629 57,235 Total other income 398,951 522,082 598,269

Research and Development Expens

Research and Development Expenses	12 Months Ended
	Jun. 30, 2021
Disclosure Of Research And Development Expenses [Abstract]
Research and Development Expenses	Note 9. Research and Development Expenses 2021 2020 2019 Restated Restated US$ US$ US$ Research project costs 25,891,851 12,064,008 22,419,712 Total research and development expenses 25,891,851 12,064,008 22,419,712 (1) The research project costs relate to the research programs in respect to the treatment of eye diseases by OPT‑302.

Expenses

Expenses	12 Months Ended
	Jun. 30, 2021
Expense By Nature [Abstract]
Expenses	Note 10. Expenses 2021 2020 2019 Restated Restated US$ US$ US$ (a) Administrative expenses Employee benefits expenses: Salaries and fees 1,794,840 1,424,237 1,441,522 Cash bonuses 479,501 193,588 295,626 Superannuation 188,543 141,019 155,218 Share-based payments expense 3,897,638 732,688 685,409 Total employee benefits expense 6,360,522 2,491,532 2,577,775 Other expenses: Insurance 4,419,433 335,786 269,060 Investor relations costs 285,071 254,212 293,313 Audit and accounting 647,549 221,410 98,553 Travel expenses 1,459 44,521 59,994 Payroll tax 18,766 134,845 62,237 Legal fees 83,605 372,431 16,025 Advisory fees 393,843 416,082 — Consultancy costs 367,070 — — Other expenses 714,328 334,262 286,057 Total other expenses 6,931,124 2,113,549 1,085,239 Depreciation of: Equipment and furniture 15,012 14,581 14,194 Leasehold improvements — 344 9,413 Right-of-use assets 91,656 81,611 — Total depreciation expense 106,668 96,536 23,607 Loss on disposal of non-current assets 1,434 1,243 — Total administrative expenses 13,399,748 4,702,860 3,686,621 (b) Occupancy expenses Short term and low value lease expenses — 1,539 56,582 Lease incidental costs 18,445 21,733 21,533 Total occupancy expense 18,445 23,272 78,115

Net Foreign Exchange (Loss)_Gai

Net Foreign Exchange (Loss)/Gain	12 Months Ended
	Jun. 30, 2021
Net Foreign Exchange Loss Gain [Abstract]
Net Foreign Exchange (Loss)/Gain	Note 11. Net Foreign Exchange (Loss)/Gain 2021 2020 2019 Restated Restated US$ US$ US$ Net foreign exchange (loss)/gain (11,011,961 ) (265,989 ) 241,814 Total net foreign exchange (loss)/gain (11,011,961 ) (265,989 ) 241,814 Exchange differences arising on the translation of monetary items are recognized in the Statement Profit and Loss and other Comprehensive Income, except where deferred in equity as a qualifying cash flow or net investment hedge. After the Company’s US IPO where the Company raised US$128 million, the Company entered into an Australian dollar denominated term deposit worth US$100 million (AUD141.9million) maturing on February 3, 2021. The Company simultaneously entered into a foreign currency exchange contract under which the term deposit converted back to US dollars at effectively the same foreign exchange rate as when the term deposit was entered into. As the Group’s functional currency was the Australian dollar (A$) until December 31, 2020, the Group recorded a foreign exchange loss of US $ 9 m ilion in relation to this transaction .

Income Taxes

Income Taxes	12 Months Ended
	Jun. 30, 2021
Major Components Of Tax Expense Income [Abstract]
Income Taxes	Note 12. Income Taxes 2021 2020 2019 Restated Restated US$ US$ US$ (a) Income tax benefit The major components of income tax benefit are: Statement of Profit or Loss and Other Comprehensive Income Current tax Current income tax credit 4,938,846 5,708,767 10,474,432 4,938,846 5,708,767 10,474,432 Deferred tax In respect of the current year — — — Total income tax benefit recognized in the Statement of Comprehensive Income 4,938,846 5,708,767 10,474,432 (b) Current tax receivable June 30, 2021 June 30, 2020 US$ US$ Research and Development Tax Incentive Credit receivable 4,972,898 5,868,152 (c) Numerical reconciliation between aggregate income tax benefit recognized in the Statement of Profit of Loss and Other Comprehensive Income and benefit calculated per the statutory income tax rate A reconciliation between income tax benefit and the product of accounting loss before income tax multiplied by the Group’s applicable income tax rate is as follows: 2021 2020 2019 Restated Restated US$ US$ US$ Accounting loss before tax (50,283,342 ) (16,831,966 ) (25,426,380 ) At the Company's statutory income tax rate of 30% (2020:27.5%, 2019:27.5%) 15,085,003 4,628,791 6,992,255 R&D tax incentive on eligible expenses 4,938,846 5,708,767 10,474,432 Non-deductible R&D expenditure (3,420,951 ) (3,624,766 ) — Other non-deductible expenses - share-based payment expense (1,169,291 ) (201,489 ) — Amount of temporary differences and carried forward tax losses not recognized (10,494,761 ) (802,536 ) (6,992,255 ) 4,938,846 5,708,767 10,474,432 (d) Recognized deferred tax assets and liabilities in statement of financial position June 30,2021 June 30, 2020 Deferred income tax at June 30 relates to the following: Deferred tax liabilities: Interest and royalty income receivable (future assessable income) (2,344,514 ) (70,925 ) (2,344,514 ) (70,925 ) Deferred tax assets related to temporary differences: Recognition of tax losses 1,508,764 — Accrued expenses and other liabilities 205,458 303,383 Employee provisions 152,675 128,812 Other miscellaneous items 477,617 430,839 2,344,514 863,034 Less: temporary differences not recognized — (792,109 ) Net deferred tax recognized in the statement of financial position — — (e) Unrecognized temporary differences Temporary differences with respect to deferred tax assets associated with intellectual property and other miscellaneous items which have a low probability of realization are unrecognized. These amounted to nil at year end (2020: US$792,109). (f) Carry forward unrecognized tax losses The Group had income tax losses of US$20,846,641 and capital losses of US$672,934 at year end (2020: income tax losses of US$14,378,726 and capital losses of US$672,934) for which no deferred tax asset is recognized on the consolidated statement of financial position as they are currently not considered probable of realization. These tax losses are available indefinitely for offset against future assessable income subject to continuing to meet relevant statutory tests. (g) Franking credit balance Franking credits are a type of tax credit in Australia that is available to the Group’s shareholder to reduce double taxation on any dividends paid by the Group. The franking account balance at the end of the financial year at 30% (2020: 30%) is A$227,371 (2020: A$227,371), which represents the amount of franking credits available for the subsequent financial year. Franking credits are not recognized in the consolidated statement of financial position.

Earnings per Share

Earnings per Share	12 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Earnings per Share	Note 13. Earnings per Share 2021 2020 2019 Restated Restated US$ US$ US$ The following reflects the income used in the basic and diluted earnings per share computations: (a) Earnings used in calculating earnings per share Net loss attributable to ordinary equity holders of the parent (45,344,496 ) (11,123,199 ) (14,951,948 ) (b) Weighted average number of shares Weighted average number of ordinary shares on issue for basic earnings per share 320,432,814 260,795,745 232,795,371 Effect of dilution: Share options — — — Weighted average number of ordinary shares adjusted for the effect of dilution 320,432,814 260,795,745 232,795,371 Loss per share (basic and diluted in cents) (14.15 ) (4.27 ) (6.42 ) There have been no transactions involving ordinary shares or potential ordinary shares that would significantly change the number of ordinary shares or potential ordinary shares outstanding between the reporting date and the date of completion of this financial report. Diluted earnings per share is calculated as net loss divided by the weighted average number of ordinary shares and dilutive potential ordinary shares. Options granted under the Long Term Incentive (LTIP) and Non‑Executive Director Share and Option (NED Plan) plans would generally be included in the calculation due to the conditions of the issuance being satisfied. As the Group is in a loss position, the options are anti‑dilutive and, accordingly, the basic loss per share is the same as the diluted loss per share. A total number of 16,644,000 options outstanding June 30, 2021 were anti‑dilutive and were therefore excluded from the weighted average number of ordinary shares for the purpose of diluted earnings per share. These options related to the following option plans We have not declared or paid any dividends on our ordinary shared. We intend to retain any earnings for use in our business and do not currently intend to pay cash dividends on our ordinary shares. Dividends, if any, on our outstanding ordianry shares will be declared by and subject to the discretion of our board of directors, and subject to Australian law. 2021 2020 2019 NED Plan 10,000,000 6,000,000 6,000,000 LTIP 6,644,000 12,044,000 12,969,000 16,644,000 18,044,000 18,969,000 As of June 30, 2021, 11,394,000 outstanding options were exercisable as of that date (2020: 18,044,000).

Current Assets _ Cash and Cash

Current Assets – Cash and Cash Equivalents	12 Months Ended
	Jun. 30, 2021
Current Assets Cash And Cash Equivalents [Abstract]
Current Assets – Cash and Cash Equivalents	Note 14. Current Assets – Cash and Cash Equivalents June 30, 2021 June 30, 2020 Restated US$ US$ Cash at bank and in hand 15,538,510 2,077,089 Short-term deposits 102,654,667 40,573,769 Total cash and cash equivalents 118,193,177 42,650,858 Cash at bank earns interest at floating rates based on daily bank deposit rates. The carrying amounts of cash and cash equivalents represent fair value. Short term‑deposits are with two major Australian banks and are made for varying periods of between 30 and 90 days, depending on the immediate cash requirements of the Group, and earn interest at a fixed rate for the respective short‑term deposit periods. At year end, the average rate was 0.24% (2020: 1.01%). .

Current Assets - Receivables

Current Assets - Receivables	12 Months Ended
	Jun. 30, 2021
Current Assets Receivables [Abstract]
Current Assets - Receivables	Note 15. Current Assets - Receivables June 30, 2021 June 30, 2020 Restated US$ US$ Interest receivable 37,905 56,032 GST receivable 1 136,239 105,124 Other receivable 1 391,142 34,417 Total current receivables 565,286 195,573 1 The GST and other receivables are non‑interest bearing. There were no receivables with a material expected credit loss recorded during the financial year (2020: nil).

Current Assets - Prepayments

Current Assets - Prepayments	12 Months Ended
	Jun. 30, 2021
Current Prepayments [Abstract]
Current Assets - Prepayments	Note 16. Current Assets - Prepayments June 30, 2021 June 30, 2020 Restated US$ US$ R&D Contract Research Organization 12,551,398 — Insurance 1,820,059 320,521 Other prepayments 14,698 8,630 Total current prepayments 14,386,155 329,151 The R&D Contract Research Organization prepayment consists of prepayments on the Phase 3 clinical trial for OPT‑302 in order to secure sites across the world and start patient recruitment. These prepayments covered the initial startup of the Phase 3 clinical trials and are expected to be consumed within the next 12 months. The Insurance amount relates to specific Phase 3 Clinical trial insurance in place for various sites around the world covering periods to 2024. The non‑current portion of the prepayments are recorded as non‑current assets. Refer Note 19.

Non-Current Assets _ Investment

Non-Current Assets – Investments in Financial Assets	12 Months Ended
	Jun. 30, 2021
Disclosure Of Financial Instruments [Abstract]
Non-Current Assets – Investments in Financial Assets	Note 17. Non-Current Assets – Investments in Financial Assets June 30, 2021 June 30, 2020 Restated US$ US$ Listed Australian shares - at fair value 1 — 199,417 — 199,417 Details of listed Australian shares Listed Investments Ownership interest Fair value at June 2 Exchange on translation Disposal in the financial year 3 Financial value gain/(loss) recognized in OCI 4 Opening fair value 2021 Non-current investments: Optiscan Imaging Limited — — — (669,184 ) 469,767 199,417 Total listed investments — — (669,184 ) 469,767 199,417 2020 (Restated) Non-current investments: Antisense Therapeutics Ltd — (2,469 ) (335,746 ) 174,196 164,019 Optiscan Imaging Limited 1.73 % 199,417 (4,920 ) — (133,098 ) 337,435 Total listed investments 199,417 (7,389 ) (335,746 ) 41,098 501,454 1 These financial assets are investments in equity instruments and are not held for trading, they are held for medium to long‑term strategic purposes. Accordingly, the Group has elected to designate these investments in equity instruments as at FVTOCI as recognizing short‑term fluctuations in these investments’ fair value in profit or loss would not be consistent with the Group’s strategy of holding these investments for long‑term purposes and realizing their performance potential in the long run. 2 The fair value represents the share (bid) price at year end and does not include any capital gains tax or selling costs that may be applicable on the disposal of these investments. These non‑current investments in listed shares consist of investments in ordinary shares, and therefore have no fixed maturity date or coupon rate. 3 During the year ended June 30, 2021, the Group’s investment in Optiscan Imaging Limited (OIL) was sold for net proceeds of US$669,184. The increase in fair value during the year of US$469,767 was recognized in other comprehensive income. The fair value of the investment in OIL at the disposal date was US$669,184. The Group disposed of the investment in line with its Treasury and Investment Policy. During the year ended June 30, 2020, the Group disposed of its remaining investment in Antisense Therapeutics Ltd (ANP) for net proceeds of US$335,746. The increase in fair value during the year of US$174,196 was recognized in other comprehensive income. In accordance with the Group’s accounting policy, the gain remains within the fair value of investments reserve. The fair value of the investment in ANP at the disposal date was US$335,746. The Group disposed of the investment in line with its Treasury and Investments Policy. 4 A fair value increase of US$469,767 (2020: US$41,098) in the carrying value of investments has been made through other comprehensive income in the year due to a net increase in their market value in the year.

Right-of-Use Assets

Right-of-Use Assets	12 Months Ended
	Jun. 30, 2021
Disclosure Of Quantitative Information About Rightofuse Assets [Abstract]
Right-of-Use Assets	Note 18. Right-of-Use Assets Right‑of‑use asset The Group has a three‑year lease contract for its head office premises in Melbourne, Australia which commenced on July 15, 2019. The agreement does not contain any extension options. The carrying amount of the lease at June 30, 2021 and 2020 is as follows: June 30, 2021 June 30, 2020 Restated US$ US$ Right-of-Use Asset Cost Opening balance as of July 1 251,189 — Additions — 251,189 Exchange on translations 30,365 — 281,554 251,189 Right-of-Use-Asset Depreciation Opening balance as of July 1 (83,729 ) — Charge to the period (91,656 ) (81,611 ) Exchange on translation (12,317 ) (2,118 ) (187,702 ) (83,729 ) Net carrying amount of June 30 93,852 167,460 Lease liabilities Lease liabilities are as indicated below. At the commencement date of the lease of its office premises, the Group recognizes lease liabilities measured at the present value of lease payments to be made over the lease term ending on July 14, 2022, using an incremental borrowing rate of 3%. June 30, 2021 June 30, 2020 Restated US$ US$ Carrying amount at July 1 182,290 — New lease — 251,189 Payments (69,325 ) (68,899 ) Carrying amount at June 30 112,965 182,290 Maturity analysis: Year 1 124,495 105,026 Year 2 — 87,827 124,495 192,853 Less: unearned interest (11,530 ) (10,563 ) 112,965 182,290 Analyzed into: Current portion 112,965 99,745 Non-current portion — 82,545 112,965 182,290 2021 2020 (1) Restated US$ US$ Amounts recognized in profit or loss: Depreciation expense on right-of-use asset 91,656 81,611 Lease finance costs 5,782 5,148 Expense relating to leases of low value assets 7,042 6,497 104,480 93,256 (1) The adoption of IFRS 16 :Leases which became applicable on July 1, 2019 was reflected in the 2020 year, no expenditure in relation to right-of-use-assets was recognized in the 2019 year . The Group did not have any short‑term leases during the years ended June 30, 2021 and 2020. The above amounts are recorded in administrative expenses.

Non-Current Assets - Prepayment

Non-Current Assets - Prepayments	12 Months Ended
	Jun. 30, 2021
Disclosure Of Noncurrent Assets Prepayments [Abstract]
Non-Current Assets - Prepayments	Note 19. Non-Current Assets - Prepayments June 30, 2021 June 30, 2020 Restated US$ US$ Insurance 174,541 — Total non-current prepayments 174,541 — The non‑current prepayment amount relates to specific Phase 3 Clinical trial insurance in place for various sites around the world covering periods to 2024.

Current Liabilities _ Payables

Current Liabilities – Payables	12 Months Ended
	Jun. 30, 2021
Current Liabilities Payables [Abstract]
Current Liabilities – Payables	Note 20. Current Liabilities – Payables June 30, 2021 June 30, 2020 Restated US$ US$ Accounts Payable (unsecured) 1 2,417,719 4,014,818 Payroll related tax liability 83,799 39,143 Total current payables 2,501,518 4,053,961 1 Accounts Payable are non‑interest bearing and are normally settled on 30 day terms.

Current Liabilities - Provision

Current Liabilities - Provisions	12 Months Ended
	Jun. 30, 2021
Current Provisions [Abstract]
Current Liabilities - Provisions	Note 21. Current Liabilities - Provisions June 30, 2021 June 30, 2020 Restated US$ US$ Annual leave 289,043 277,469 Long service leave 202,959 163,296 Total current provisions 492,002 440,765

Non-Current Liabilities - Provi

Non-Current Liabilities - Provisions	12 Months Ended
	Jun. 30, 2021
Noncurrent Provisions [Abstract]
Non-Current Liabilities - Provisions	Note 22. Non-Current Liabilities - Provisions June 30, 2021 June 30, 2020 Restated US$ US$ Long service leave 16,915 27,643 Total non-current provisions 16,915 27,643

Contributed Equity

Contributed Equity	12 Months Ended
	Jun. 30, 2021
Contributed Equity [Abstract]
Contributed Equity	Note 23. Contributed Equity June 30, 2021 June 30, 2020 July 1, 2019 Restated Restated US$ US$ US$ (a) Ordinary shares Issued and fully paid at June 30 234,147,526 113,852,364 80,331,016 Movement in ordinary shares: Opening balance 113,852,364 80,331,016 69,788,130 Issue of shares on exercise of quoted options — — 9,069,584 Issue of shares — 33,236,520 — Issue of shares on exercise of options granted under the LTIP — 284,828 — Issue of shares on Nasdaq listing net of issuance cost $10,126,959 105,477,591 — — Issue of shares on exercise of pre-funded warrants net of issuance cost $1,099,412 11,546,029 — — Transfer from option reserve 3,271,542 — 1,473,302 234,147,526 113,852,364 80,331,016 Ordinary shares on issue: No: No: No: Opening balance 269,157,769 249,414,839 202,637,888 Issue of shares on exercise of quoted options — — 46,776,951 Issue of shares — 19,742,930 — Issue of shares on exercise of options granted under the LTIP 5,845,804 — — Issues of shares on Nasdaq listing 68,506,400 — — Issue of share on exercise of pre-funded warrants 7,493,568 — — 351,003,541 269,157,769 249,414,839 Fully paid ordinary shares have no par value, carry one vote per share and carry the right to dividends. Issued capital at June 30, 2021 amounted to US$234,147,526 (351,003,541 fully paid ordinary shares) net of share issue costs and tax. During the year ended June 30, 2021 the Company issued 68,506,400 ordinary shares on Nasdaq listing for net proceeds of US$105,477,591 as well as issued 7,493,568 pre‑funded warrants for net proceeds of US$11,546,029. At June 30, 2021, the company had 6,750,000 Non‑Executive Director options that remain unexercised with expiry of November 2022 for 1,500,000 options, October 2023 for 3,000,000 options and January 2024 for 2,250,000 options. Options granted to directors and employees The company has two share‑based payment schemes, the Long Term Incentive Plan (LTIP) and Non‑Executive Director Share and Option Plan. Options to subscribe for the Company’s shares have been granted under these plans to certain employees and directors. The company granted 7,000,000 options over ordinary shares under these plans during the year ended June 30, 2021 (note 31). These options had a weighted average fair value at their grant date of US$1.03 per option. During June 30, 2021 8,400,000 options granted under the LTIP and NED Plan were exercised for US $ 3,271,542 . No options were granted under the Plans during the year ended June 30, 2020. June 30, 2021 June 30, 2020 July 1, 2019 Restated Restated US$ US$ US$ (b) Pre-funded warrants Movement in pre-funded warrants: Opening balance — — — Issue of pre-funded warrants in a US initial public offering 12,645,441 — — Cost of issue of pre-funded warrants (1,099,412 ) — — Issue of shares on exercise of pre-funded warrants (11,546,029 ) — — — — — Pre-funded warrants on issue: No: No: No: Opening balance — — — Issue of pre-funded warrants in a US Initial public offering 7,493,600 — — Exercise of pre-funded warrants (7,493,568 ) — — Forfeiture on exercise (32 ) — — — — — The Company issued 7,493,600 pre‑funded warrants for US$11,546,029 net of issue costs in respect of the US initial public offering. The pre‑funded warrants were unquoted, having no voting or dividend rights and are exercisable to ADS’s at an exercise price of US$0.00001 per pre‑funded warrant on a one for one basis with no expiry date. During the year all pre‑funded warrants that were issued October 20, 2020 were exercised via two trenches, 4,147,136 warrants in March 2021 and 3,346,432 warrants in June 2021 converted to ADS’s. (c) Capital management The Group is not subject to any externally imposed capital requirements. When managing share capital, management’s objective is to ensure the entity continues as a going concern as well as to provide benefits to shareholders and for other stakeholders. In order to maintain or achieve an appropriate capital structure, the Company may issue new shares or reduce its share capital, subject to the provisions of the Company’s constitution. The Group only commits to significant R&D expenditure when this is fully funded either by existing funds or further equity raises.

Accumulated Losses and Reserves

Accumulated Losses and Reserves	12 Months Ended
	Jun. 30, 2021
Disclosure Of Reserves Within Equity [Abstract]
Accumulated Losses and Reserves	Note 24. Accumulated Losses and Reserves June 30, 2021 June 30, 2020 July 1, 2019 Restated Restated US$ US$ US$ (a) Movements in accumulated losses were as follows: Balance of July 1 (78,779,486 ) (67,656,287 ) (52,704,339 ) Net loss for the period (45,344,496 ) (11,123,199 ) (14,951,948 ) Balance of June 30 (124,123,982 ) (78,779,486 ) (67,656,287 ) (b) Reserves Fair value of Investments reserve (i) 1,085,411 551,409 517,700 Share-based payments reserve (ii) 4,087,650 3,116,080 2,401,769 Foreign translation reserve (iii) 20,089,163 5,827,605 6,257,941 Total reserves 25,262,224 9,495,094 9,177,410 (i) Movement in fair value of investments reserve: Opening balance 551,409 517,700 353,604 Fair value on gains on investments in financial assets 469,767 41,098 181,687 Exchange on translation 64,235 (7,389 ) (17,591 ) Closing balance 1,085,411 551,409 517,700 (ii) Movement in share-based payments reserve: Opening balance 3,116,080 2,401,769 1,816,817 Share-based payments expense 3,897,638 732,688 685,409 Exercise of options (3,271,542 ) (284,828 ) — Exchange on translation 345,474 266,451 (100,457 ) Closing balance 4,087,650 3,116,080 2,401,769 (iii) Movement in foreign translation reserve: Opening balance 5,827,605 6,257,941 7,530,571 (Gains)/loss on translation 14,261,558 (430,336 ) (1,272,630 ) Closing balance 20,089,163 5,827,605 6,257,941 (iv) Movement in option reserve Opening balance — — 1,473,302 Transfer to contributed equity — — (1,473,302 ) Closing balance — — — (c) Nature and purpose of reserves Fair value of investments reserve This reserve records fair value changes on listed investments. Share‑based payment reserve This reserve is used to record the value of equity benefits provided to executives and employees as part of their remuneration. Foreign currency translation reserve The reserve records the value of foreign currency movements on translation of financial statements from A$ to US$ Option reserve On 25 November 2014 the company issued options to purchase 49,726,672 ordinary shares with an exercise price of $0.19 expiring on 25 November 2018. The fair value of the options at their issue date of $1,473,302 was recognized in the option reserve. The same amount, US$1,473,302, was transferred to contributed equity on 25 November 2018 following the exercise and expiry of all quoted options. The balance on the option reserve at 30 June 2021, 2020 and 20 19 was nil .

Financial Risk Management Objec

Financial Risk Management Objectives and Policies	12 Months Ended
	Jun. 30, 2021
Disclosure Of Risk Management Strategy Related To Hedge Accounting [Abstract]
Financial Risk Management Objectives and Policies	Note 25. Financial Risk Management Objectives and Policies The Group’s principal financial assets comprise cash, receivables, short‑term deposits and investments in listed shares. The Group manages its exposure to key financial risks, including interest rate and currency risk in accordance with the Group’s financial risk management practices. The objective is to support the delivery of the Group’s financial targets whilst protecting future financial security. The Group’s other various financial assets and liabilities, such as receivables and payables, arise directly from its operations. The main risks arising from the Group’s financial assets and liabilities are interest rate risk, foreign currency risk, equity securities price risk and liquidity risk. The Group uses different methods to measure and manage different types of risks to which it is exposed. These include monitoring levels of exposure to interest rate and foreign exchange risk and assessments of market forecasts for interest rates and foreign exchange rates. Liquidity risk is monitored through future rolling cash flow forecasts. The board reviews and agrees policies for managing each of these risks as summarized below. Risk exposures and responses The Group has investigated the main financial risk areas which could impact on its financial assets and determined the impact on post tax (losses) or profits for a range of sensitivities. These can be seen in the post tax (loss)/profit impact for each risk area. For each risk area, the equity impact relates solely to reserve movements and excludes movements in accumulated losses as the impact of these can be seen within the post tax (loss)/profit impact. (i) Interest rate risk The Group’s exposure to market interest rates relates primarily to the short‑term deposits. The deposits are held with two of Australia’s largest banks. The objective of managing interest rate risk is to minimize the Group’s exposure to fluctuations in interest rates that might impact its interest income and cash flow. To manage interest rate risk, the Group invests the majority of its cash in short‑term deposits for varying periods of between 30 days and 90 days, depending on the short and long‑term cash requirements of the Group which is determined based on the Group’s cash flow forecast. This consideration also takes into account the costs associated with recalling a term deposit should early access to cash and cash equivalents be required. Cash is not locked into long‑term deposits at fixed rates so as to mitigate the risk of earning interest below the current floating rate. The Group does not have any borrowings (2020: nil). The following sensitivity analysis (an annual effect) is based on the interest rate risk exposures at June 30, 2021 and 2020. At June 30, 2021, if interest rates moved, with all variables held constant, post tax (loss)/profit and equity would have been affected as illustrated in the following table: Post tax (loss)/profit impact 2021 2020 2019 Restated Restated US$ US$ US$ Judgments of reasonably possible movements +0.50% (50 basis points) (2020:+0.50%) 359,442 137,676 50,490 -0.50% (50 basis points) (2020:-0.50%) (359,442 ) (137,676 ) (50,490 ) The post tax figures include an offset for unrecognized tax losses (bringing the tax effect to nil ) for the year ended June 30, 2021 (2020: nil ,2019: nil ). Significant assumptions used in the interest rate sensitivity analysis include: • The reasonably possible movement of 0.5% was calculated by taking the interest rates as of balance date, moving these by plus and minus 0.5% and then re‑calculating the interest on term deposits with the ‘new‑interest‑rate’. • The net exposure at balance date is representative of what the Group was and is expecting to be exposed to in the next twelve months from balance date . (ii) Price risk The Group’s investment in listed shares is exposed to equity securities price risk and as such their fair values are exposed to fluctuations as a result of changes in market prices. Equity price risk is the risk that the fair value of equities will decrease as a result of share price movements. The Group’s equity investments are publicly traded on the ASX and are designated and accounted for as investments in financial assets. The investments in listed shares are not held for short‑term trading. Their values are reviewed regularly by management and the board. The strategy for realizing any part of these investments is determined based on the liquidity of the respective stocks, potential off‑market acquirers and likely developments in their values based on publicly available information. At June 30, 2021 and 2020, had the share price moved with all other variables held constant, post tax (loss)/profit and equity would have been affected as illustrated in the table below: 2021 2020 2019 Restated Restated US$ US$ US$ Judgments of reasonably possible movements Impact of loss Impact on equity Impact of loss Impact on equity Impact of loss Impact on equity Change in variables 10% increase in listed share price — — 13,450 13,450 35,102 35,102 10% decrease in listed share price — — (13,450 ) (13,450 ) (35,102 ) (35,102 ) (iii) Foreign currency risk As a result of services provided by non‑related entities in the United States, Canada, United Kingdom and Europe, part of the Group’s monetary assets and liabilities are affected by movements in the exchange rate. The Group does not enter into any hedging transactions. At the reporting date, the Group has the following exposure to foreign currencies. The functional currency of the Group changed during the year ended June 30, 2021. Accordingly, the 2021 table illustrates the Group’s exposure to Australian dollars and the 2020 table illustrates the Group’s exposure to US dollars: Consolidated 2021 AUD EURO GBP CAD Financial assets Cash 35,646,457 — — — Receivables 5,513,541 — — — Financial liabilities Payables (1,276,164 ) (41,872 ) (1,290 ) Other financial liabilities — — — — Net exposure 39,883,834 (41,872 ) — (1,290 ) Consolidated 2020 USD EURO GBP CAD Financial assets Cash 42,417 — — — Receivables 25,821 — — — Financial liabilities Payables (3,355,050 ) (10,238 ) (23,481 ) — Other financial liabilities (163,547 ) — — — Net exposure (3,450,359 ) (10,238 ) (23,481 ) — The following sensitivity is based on the foreign currency risk exposures in existence at June 30, 2021 and 2020. At June 30, 2021 and 2020, had the United States dollar (2020: Australian dollar) moved with all other variables held constant, post tax (loss) profit and equity would have been affected as illustrated in the table below: Post tax (loss)/profit impact 2021 2020 2019 Restated Restated US$ US$ US$ Judgments of reasonably possible movements Consolidated AUD/USD +10% (2020:+10%) (2,538,062 ) 219,569 200,257 AUD/USD -10% (2020:-10%) 3,102,076 (268,361 ) (244,759 ) The reasonably possible movements at June 30, 2021 are higher than at June 30, 2020 and June 30, 2019 due mainly to the higher net exposure to the Australian dollar due to significant cash at bank deposits. There was minimum or insignificant exposure to the GBP, Euro and CAD during the current financial year. Significant assumptions used in the foreign currency exposure sensitivity analysis include: (iv) The reasonably possible movement of 10% was calculated by taking the currency spot rates as of balance date, moving these by 10% and then re‑converting the currencies into US with the ‘new‑spot‑rate’. This methodology reflects the translation methodology undertaken by the Group. (v) The net exposure at balance date is representative of what the Group was and is expecting to be exposed to in the next twelve months from balance date. (vi) Management believes the balance date risk exposures are representative of the risk exposure inherent in the financial instruments. (iv) Credit risk Credit risk is associated with those financial assets of the Group which comprise cash and cash equivalents, receivables and listed investments. The Group’s exposure to credit risk arises from default of the counter party, with a maximum exposure equal to the carrying amount of these investments. Credit risk is considered minimal as the Group transacts with reputable recognized Australian banks. (v) Liquidity risk Liquidity risk arises from the financial liabilities of the Group and the Group’s subsequent ability to meet their obligations to repay their financial liabilities as and when they fall due. The Group has minimal liquidity risk because of the high balances of cash and cash equivalents; however, the Group manages liquidity risk by maintaining adequate reserves and by monitoring forecast and actual cash flows and by matching the maturity profiles of financial assets and liabilities. The financial liabilities of the Group relate to trade payables that are all expected to be paid within 12 months. The Group’s objective is to maintain an appropriate cash asset balance to fund its operations. (vi) Fair value The Group has investments in listed equities which are calculated using the quoted prices in an active market and are considered level 1 fair value measurements. The Group does not have any derivative investments where the fair value is estimated using inputs other than quoted prices that are observable for the asset or liability, either directly (as prices) or indirectly (i.e. derived from prices). The Group also does not hold any financial instruments where fair value measurement uses observable inputs that require significant adjustments based on observable inputs to estimate its value. Shortly after the Company’s US IPO where the Company raised USD 128 million, the Company entered into an Australian dollar denominated term deposit worth USD 100 million (AUD 141.9 million), maturing on 3 February 2021. The Company simultaneously entered into a foreign currency exchange contract under which the term deposit would be converted back to US dollars at effectively the same foreign exchange rate as when the term deposit was entered into. The financial liability represents the marked to market value of this foreign currency exchange contract held at 31 December 2020. Subsequent to 31 December 2020, upon maturity and settlement of the term deposit and foreign exchange contract on 3 February 2021, the Australian dollar denominated term deposit was converted back to US dollars for a value of USD 100 million plus interest earned of AUD 116 thousand. Details of the fair value of the investment in financial assets are disclosed in note 17 of the financial statements. The fair value of financial assets and financial liabilities in the consolidated statement of financial position at June 30, 2021 and 2020 is the same as their carrying amounts. The methods for estimating fair value are also outlined in the relevant notes to the financial statements.

Related Party Disclosures

Related Party Disclosures	12 Months Ended
	Jun. 30, 2021
Related Party Transactions [Abstract]
Related Party Disclosures	Note 26. Related Party Disclosures (a) Subsidiarie s The consolidated financial statements include the financial statements of Opthea Limited and its subsidiaries in the following table: Parent entity % equity interest 2021 2020 2019 % % % Vegenics Pty Ltd 1 100 100 100 Opthea US Inc 2 100 — — (1) Opthea Limited is the ultimate parent entity. Vegenics Pty Ltd is incorporated in Australia and has the same financial year as Opthea Limited. (2) Opthea Limited is the ultimate parent entity. Opthea US Inc was incorporated in the United States in May 2021 and has the same financial year as Opthea Limited. (b) Transactions with related parties Balances and transactions between the Company and its subsidiaries, a related party of the Company, have been eliminated on consolidation and are not disclosed in this note.

Commitments

Commitments	12 Months Ended
	Jun. 30, 2021
Commitments [Abstract]
Commitments	Note 27. Commitments (i) Lease commitments – Group as lessee Lease commitments are in respect of low value leases which have not been recognized in the Statement of Financial Position. These leases are expensed on a straight‑line basis over the term of the lease. 2021 2020 2019 Restated Restated US$ US$ US$ Within one year 5,304 4,497 4,936 After one year but not more than five years 8,398 11,619 — 13,702 16,116 4,936 (ii) Research projects and license commitments The Group has entered into research and development contracts and intellectual property license agreements with various third parties in respect of services for the Phase 3 DME clinical trial and the clinical grade manufacture of OPT‑302. Expenditure commitments relating to these and intellectual property license agreements are payable as follows: 2021 2020 2019 Restated Restated US$ US$ US$ Within one year 26,377,778 7,660,325 5,460,972 After one year but not more than five years 2,347,060 293,815 60,000 After more than five years — 75,000 90,000 28,724,838 8,029,140 5,610,972 Currently, the biggest Research contract has a 60 day termination clause and all commitments have been limited to a six month commitment.

Contingencies

Contingencies	12 Months Ended
	Jun. 30, 2021
Disclosure Of Contingent Liabilities [Abstract]
Contingencies	Note 28. Contingencies The Group is party to various research agreements with respect to which a commitment to pay is contingent on the achievement of research milestones. Assuming all milestones are achieved within the time‑frames stipulated in the contracts, those which could become payable in less than one year total US$ nil Under these license/collaboration agreements, payments are to be made only if certain research and clinical development milestones are achieved and royalties may become payable on any eventual sales of products developed under these agreements. The group had a bank guarantee outstanding at June 30, 2021 in respect of a rental deposit for its office premises of US$43,000 (2020: US$39,391).

Cash Flow Statement Reconciliat

Cash Flow Statement Reconciliation	12 Months Ended
	Jun. 30, 2021
Cash Flow Statement Reconciliation [Abstract]
Cash Flow Statement Reconciliation	Note 29 Cash Flow Statement Reconciliation 2021 2020 2019 Restated Restated US$ US$ US$ (a) Reconciliation to cash at the end of the year Cash at bank and in hand (note 14) 118,193,177 42,650,858 15,121,820 118,193,177 42,650,858 15,121,820 (b) Reconciliation of net loss after tax to net cash flows from operations Net loss for the year (45,344,496 ) (11,123,199 ) (14,951,948 ) Adjustments for: Income tax benefit recognized in profit or loss (4,938,846 ) (5,708,767 ) (10,474,432 ) Depreciation of non-current assets 15,012 14,926 23,607 Depreciation of right-of-use assets 91,656 81,611 0 Share-based payments 3,897,638 732,688 685,409 Net exchange differences 11,011,961 265,989 (241,814 ) Changes in: Payables (1,552,443 ) (125,492 ) (1,209,513 ) Receivables (369,712 ) 12,127 83,936 Prepayments (14,231,546 ) (30,994 ) (81,681 ) Provisions 40,510 72,794 26,823 Net cash flows used in operating activities before tax (51,380,266 ) (15,808,317 ) (26,139,613 ) R&D tax incentive received 5,834,099 10,118,697 9,097,526 Net cash flows used in operating activities (45,546,167 ) (5,689,620 ) (17,042,087 ) 2021 2020 2019 Restated Restated US$ US$ US$ (c) Reconciliation of borrowings arising from financing activities Balance at July 1 167,460 — — Non-cash addition 1 — 251,189 — Payment of lease liabilities (87,373 ) (66,781 ) — Exchange on translation 13,765 (16,948 ) — Balance at June 30 93,852 167,460 — 1 Non‑cash addition represents the new lease on the Company’s office premises in Melbourne, Australia that commenced on July 15, 2019.

Key Management Personnel

Key Management Personnel	12 Months Ended
	Jun. 30, 2021
Disclosure Of Transactions Between Related Parties [Abstract]
Key Management Personnel	Note 30. Key Management Personnel (a) Compensation of Key Management Personnel 2021 2020 2019 Restated Restated US$ US$ US$ Short-term employee benefits 1,099,081 680,954 715,027 Post-employment benefits 79,550 64,632 67,928 Share-based payments expense 3,897,638 420,751 532,952 5,076,269 1,166,337 1,315,907 (b) Other transactions and balances with director and key management personnel and their related parties There were no director and key management personnel related party transactions during the current or prior financial year.

Share-Based Payments

Share-Based Payments	12 Months Ended
	Jun. 30, 2021
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Abstract]
Share-Based Payments	Note 31. Share-Based Payments (a) The expense recognized for share‑based payments during the year is shown in the table below: 2021 2020 2019 Restated Restated US$ US$ US$ Expense arising from equity-settled share-based payment transactions: Director and employee services received 3,897,638 732,688 685,409 3,897,638 732,688 685,409 (b) During the 2015 financial year, the Group introduced an ownership‑based compensation scheme for non‑executive directors, executives and senior employees, the Long Term Incentive Plan (LTIP) and Non‑Executive Directors Share and Option Plan (NED Plan). In accordance with the terms of the plans, as approved by shareholders at the 2014 annual general meeting, eligible non‑executive directors, executives and senior employees with the Group may be granted options to purchase ordinary shares. Each employee share option converts into one ordinary share of Opthea Limited on exercise. No amounts are paid or payable by the recipient on receipt of the option. The options carry neither rights to dividends nor voting rights and are not transferable. Options may be exercised at any time from the date of vesting to the date of their expiry. The number of options granted is subject to approval by the board and rewards executives and senior employees to the extent of the Group’s and the individual’s achievement judged against both qualitative and quantitative criteria as determined by the board on a case by case basis. The vesting condition of options granted under the LTIP and NED Plan is continuous service. Options/Rights services Grant date Grant date fair value US$ Exercise price US$ Expiry date Vesting date LTIP - director FY2016 March 7,2016 0.14 0.36 March 7, 2021 June 30, 2016 LTIP - director FY2019 November 29, 2018 0.15 0.625 November 29, 2022 November 29, 2019 LTIP - employees FY2016 March 31, 2016 0.18 0.37 January 1, 2022 January 1, 2017 LTIP - employees FY2018 August 23, 2017 0.26 0.92 January 1, 2023 June 30, 2018 LTIP - employees FY2019 April 3, 2019 0.18 0.608 April 3, 2023 April 3, 2021 NED Plan FY2016 March 7,2016 0.14 0.36 March 7, 2021 June 30, 2016 NED Plan FY2019 November 29, 2018 0.15 0.625 November 29, 2022 November 29, 2019 NED Plan FY2021 October 12, 2020 1.05 3.24 October 11, 2024 October 12, 2020 NED Plan FY2021 October 12, 2020 1.05 3.24 October 11, 2024 October 12, 2021 NED Plan FY2021 October 12, 2020 1.05 3.24 October 11, 2024 October 12, 2022 NED Plan FY2021 October 12, 2020 1.05 3.24 October 11, 2024 October 12, 2023 NED Plan FY2021 October 12, 2020 1.24 2.16 October 11, 2024 October 12, 2020 NED Plan FY2021 October 12, 2020 1.24 2.16 October 11, 2024 October 12, 2021 NED Plan FY2021 October 12, 2020 1.24 2.16 October 11, 2024 October 12, 2022 NED Plan FY2021 October 12, 2020 1.24 2.16 October 11, 2024 October 12, 2023 NED Plan FY2021 January 19, 2021 0.88 1.56 January 18, 2025 January 19, 2021 NED Plan FY2021 January 19, 2021 0.88 1.56 January 18, 2025 January 19, 2022 NED Plan FY2021 January 19, 2021 0.88 1.56 January 18, 2025 January 19, 2023 NED Plan FY2021 January 19, 2021 0.88 1.56 January 18, 2025 January 19, 2024 There has been no alteration of the terms and conditions of the above share‑based payment arrangements since the grant date. (c) Where relevant, the expected life used in the model has been adjusted based on management’s best estimate for the effects of non‑transferability, exercise restrictions (including the probability of meeting market conditions attached to the option), and behavioral considerations. Expected volatility is based on the historical share price volatility over the past 4 or 5 years Options/Rights services Grant date share price US$ Exercise price US$ Fair value per option US$ Expected volatility Option life Dividend yield Risk free interest rate Model used LTIP - director FY2016 0.28 0.36 0.14 65 % 5 years 0 % 2.09 % Binomial LTIP - director FY2019 0.42 0.63 0.15 58 % 4 years 0 % 2.04 % Binomial LTIP - employees FY2016 0.54 0.37 0.18 65 % 5 years 0 % 2.09 % Binomial LTIP - employees FY2018 0.34 0.92 0.26 66 % 5 years 0 % 2.09 % Binomial LTIP - employees FY2019 0.48 0.61 0.18 57 % 4 years 0 % 2.04 % Binomial NED Plan FY2016 0.28 0.36 0.14 65 % 5 years 0 % 2.09 % Binomial NED Plan FY2019 0.42 0.63 0.15 58 % 4 years 0 % 2.04 % Binomial NED Plan FY2021 2.19 2.16 1.24 77.25 % 4 years 0 % 0.25 % Binomial NED Play FY2021 2.19 3.24 1.05 77.25 % 4 years 0 % 0.25 % Binomial NED Plan FY2021 1.56 1.56 0.88 77.01 % 4 years 0 % 0.25 % Binomial (d) The following reconciles the share options outstanding at the beginning and end of the year: 2021 2020 2019 Number of options and rights Weighted average exercise price US$ Number of options and rights Weighted average exercise price US$ Number of options and rights Weighted average exercise price US$ Balance at beginning of year 18,044,000 0.50 18,919,000 0.50 10,075,000 0.39 Granted during the year: To employees and directors under the LTIP and NED Plan 7,000,000 2.21 — — 8,844,000 0.62 Exercised during the year (8,400,000 ) 0.36 (875,000 ) 0.37 — — Expired during the year — — — — — — Balance at end of the year 16,644,000 1.28 18,044,000 0.50 18,919,000 0.50 Exercisable at end of year 11,394,000 0.86 18,044,000 0.50 9,905,000 0.37 The share options outstanding at the end of the year had a weighted average exercise price of US $0.86 (2020: US$0.50, 2019: US$0.37) and a weighted average remaining contractual life of 628 days (2020: 626 days, 2019: 716 days).

Events After the Balance Sheet

Events After the Balance Sheet Date	12 Months Ended
	Jun. 30, 2021
Disclosure Of Nonadjusting Events After Reporting Period [Abstract]
Events After the Balance Sheet Date	Note 32. Events After the Balance Sheet Date No matters or circumstances have arisen since the end of the reporting period, which significantly affected, or may significantly affect, the operations of the Group, the results of those operations, or the state of affairs of the Group in future financial years.

Summary of Accounting Policies

Summary of Accounting Policies (Policies)	12 Months Ended
	Jun. 30, 2021
Description Of Business And Summary Of Significant Accounting Policies [Abstract]
Basis of measurement	Basis of measurement The consolidated financial statements have been prepared on a historical cost basis, except for the investments classified as financial assets, which have been measured at fair value. All amounts are presented in United States dollars unless otherwise stated. Change in presentation and functional currencies Functional currency An entity’s functional currency is the currency of the primary economic environment in which the entity operates. During the current year, the Group’s operations have continued to move further towards being US$ denominated and several other factors during the period have also contributed to the Group changing its functional currency during the year, such as the completion of U.S. initial public offering (IPO) and the Nasdaq listing in October 2020, opening a US subsidiary in May 2021 for a planned expansion into the US, and expanding the Board of Directors with the appointment of four US based Directors. A significant element in the Group’s assessment to change the functional currency resulted from the significant increase in expenses denominated in US dollars relating to advanced clinical trials since the commencement of Phase 3 trials in March 2021. These changes, as well as the fact that the Group’s principal source of financing is now the U.S. capital market and all of the Group’s budgeting and planning is conducted solely in dollars led to the Company determining that the U.S. dollar (US$) best represents the currency of the primary economic environment in which the entity now operates. Accordingly, the Group changed its functional currency from Australian dollar (A$) to U.S. dollar (US$) effective January 1, 2021. The change in functional currency has been applied prospectively with effect from January 1, 2021 in accordance with the requirements of the Accounting Standards. To give effect in functional currency, the assets and liabilities of the Group were converted into U.S. dollars at a fixed exchange rate of US$1: A$1.2973. Presentation Currency Following the change in functional currency, the Group changed its presentation currency from Australian dollars (A$) to US$. The change in presentation currency was made to better reflect the Group’s business activities and to enhance access to U.S. capital markets. Prior to the change, the Group reported its financial statements in Australian dollars (A$). A change in presentation currency is a change in accounting policy which is accounted for retrospectively, including the restatement of 2019 Balance Sheet. In making this change in presentation currency, the Group followed the requirements set out in IAS 21 The Effects of Changes in Foreign Exchange Rates
Basis of consolidation	Basis of consolidation The consolidated financial statements incorporate the financial statements of the Company and its subsidiaries. Control is achieved when the Company: • Has power over the investee; • Is exposed, or has rights, to variable returns from its involvement with the investee; and • Has the ability to use its power to affect its returns. Consolidation of a subsidiary begins when the Company obtains control over the subsidiary and ceases when the Company loses control of the subsidiary. All intragroup assets and liabilities, equity, income, expenses and cash flows relating to transactions between members of the Group are eliminated in full on consolidation.
Foreign currency translation	Foreign currency translation i. Functional and presentation currency As of January 1, 2021 the Group determined that its functional and presentation currency had changed from Australian Dollars to United States Dollars. Therefore, the functional and presentation currency of the Group is the United States dollars (US$). The prior year financial information has been restated to United States dollars. ii. Transactions and balances Transactions in foreign currencies are initially recorded in the functional currency by applying the exchange rates ruling in place at the date of the transaction. Monetary assets and liabilities denominated in foreign currencies are retranslated at the rate of exchange ruling in place at the reporting date. Non‑monetary items that are measured in terms of historical cost in a foreign currency are translated using the exchange rate as of the date of the initial transaction. Non‑monetary items measured at fair value in a foreign currency are translated using the exchange rates at the date when the fair value was determined.
Financial assets and liabilities	Financial assets and liabilities Recognition and derecognition of financial assets Purchases and sales of financial assets that require delivery of assets within the time frame generally established by regulation or convention in the marketplace are recognized on the trade date, i.e., the date that the Group commits to purchase the asset. Financial assets are derecognized when the right to receive cash flows from the financial assets has expired or when the entity transfers substantially all the risks and rewards of the financial assets. If the entity neither retains nor transfers substantially all of the risks and rewards, it derecognizes the asset if it has transferred control of the assets. When financial assets are recognized initially, they are measured at fair value, plus directly attributable transaction costs. Cash and cash equivalents Cash and cash equivalents in the statement of financial position comprise cash at bank and in hand and short‑term deposits with an original maturity of three months or less that are readily convertible to known amounts of cash and which are subject to an insignificant risk of changes in value. For the purposes of the statement of cash flows, cash and cash equivalents consist of cash and cash equivalents as defined above. Other receivables Other receivables generally comprise bank interest receivable, other receivables from external parties and Goods and Services Tax (GST) credits receivable and are recognized and carried at original invoice amount less an allowance for any uncollectible amounts. The amounts are usually received within 30 to 60 days of recognition. The Group measures the loss allowance for receivables at an amount equal to lifetime expected credit losses (ECL). The ECL on receivables are estimated under the simplified approach as permitted under IFRS 9 “Financial Instruments.” This uses a provision matrix by reference to past experience of the debtor and an analysis of the debtor’s current financial position, adjusted for factors that are specific to the debtors and general economic conditions of the industry in which the debtors operate. The Group writes off a receivable when there is information indicating that the debtor is in severe financial difficulty and there is no realistic prospect of recovery. Investments Investments in financial assets comprise of the Group’s non‑current investments in listed companies. On initial recognition, the Group may make an irrevocable election (on an instrument‑by‑instrument basis) to designate investments in equity instruments as fair value through other comprehensive income (FVTOCI). Designation at FVTOCI is not permitted if the equity instrument is held for trading. Investments in equity instruments at FVTOCI are initially measured at fair value plus transaction costs. Subsequently, they are measured at fair value with gains or losses arising from changes in the fair value recognized in other comprehensive income and accumulated in the fair value of investments reserve. The fair values of investments in financial assets that are actively traded in organized financial markets is determined by reference to quoted market bid prices at the close of business on the reporting date. The cumulative gain or loss is not reclassified to profit or loss on disposal of the equity instruments. Dividends on these investments in equity instruments are recognized in profit or loss in accordance with International Financial Reporting Standards. Finance income Almost all of the Group’s finance income is earned on short‑term bank deposits, and as such, finance income is recognized when the Group’s right to receive the payment is established. Payables Payables are carried at amortized cost and due to their short‑term nature, they are not discounted. They represent liabilities for goods and services provided to the Group prior to the end of the financial year that are unpaid and arise when the Group becomes obliged to make future payments in respect of the purchase of these goods and services. The amounts are unsecured and are usually paid within 30 days of recognition.
Other financial liabilities	Other financial liabilities Other financial liabilities in the consolidated statement of financial position represent the year end marked‑to‑market value of forward rate foreign exchange contracts to purchase US dollars (Contracts) which were entered into prior to the change in functional currency which took place on January 1, 2021. These Contracts were used to settle US dollar denominated payables and expired within one year. The foreign exchange loss on recognition of the Contracts was included in ‘net foreign exchange gain/(loss)’ in the consolidated statement of profit or loss and other comprehensive income.
Plant and equipment	Plant and equipment Plant and equipment are stated at historical cost less accumulated depreciation and any accumulated impairment losses. Depreciation is calculated on a straight‑line basis over their useful economic lives as follows: • Equipment and furniture – 3 to 10 years; and • Leasehold improvements – 8 years or the term of the lease if shorter. The assets’ residual values, useful lives and amortization methods are reviewed, and adjusted if appropriate, at each financial year end. An item of plant and equipment is derecognized upon disposal or when no further economic benefits are expected from its use or disposal.
Leases	Leases The Group assesses at contract inception whether a contract is, or contains, a lease. A contract is, or contains, a lease if the contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. The Group applies a single recognition and measurement approach for all leases, except for short‑term leases and leases of low‑value assets. The Group recognizes lease liabilities to make lease payments and right‑of‑use assets representing the right to use the underlying assets. Right‑of‑use assets Right‑of‑use assets are recognized at the commencement date of the lease (that is the date the underlying asset is available for use). Right‑of‑use assets are measured at cost, less any accumulated depreciation and any impairment losses, and adjusted for any remeasurement of lease liabilities. The cost of right‑of‑use assets include the amount of lease liabilities recognized, initial direct costs incurred, and lease payments made at or before the commencement date less any lease incentives received. Right‑of‑use assets are depreciated on a straight‑line basis over the shorter of the lease terms and the estimated useful lives of the assets. Lease liabilities Lease liabilities are recognized at the commencement date of the lease at the present value of lease payments to be made over the lease term. The lease payments include fixed payments (including in‑substance fixed payments) less any lease incentives receivable. In calculating the present value of lease payments, the Group uses its incremental borrowing rate at the lease commencement date because the interest rate implicit in the lease is not readily determinable. The incremental borrowing rate is determined using market yields on bonds with similar terms to maturity. After the commencement date, the amount of lease liabilities is increased to reflect the accretion of interest and reduced for the lease payments made. In addition, the carrying amount of lease liabilities is remeasured if there is a modification, a change in the lease term, a change in lease payments (e.g., a change to future lease payments resulting from a change in an index or rate). Leases of low‑value assets For short‑term leases (lease term of 12 months or less) and leases of low‑value assets (such as photo copiers and telephones), the Group has opted to recognize a lease expense on a straight‑line basis as permitted by IFRS 16. This expense is presented within “administrative expenses” in the consolidated statement of profit or loss and other comprehensive income.
Research and development costs	Research and development costs Research costs are expensed as incurred. An intangible asset arising from the development expenditure on an internal project will only be recognized when the Group can demonstrate the technical feasibility of completing the intangible asset so that it will be available for use or sale, its intention to complete and its ability to use or sell the asset, how the asset will generate future economic benefits, the availability of resources to complete the development and the ability to measure reliably the expenditure attributable to the intangible asset during its development. As of June 30, 2021, 2020 and 2019, the Group is in the research phase and has not capitalized any development costs to date.
Provisions and employee benefits	Provisions and employee benefits i. Wages, salaries, annual leave and sick leave Liabilities for wages and salaries, including non‑monetary benefits and annual leave expected to be settled within 12 months of the reporting date are recognized in current provisions in respect of employees’ services up to the reporting date. They are measured at the amounts expected to be paid when the liabilities are settled. Expenses for non‑accumulating sick leave are recognized when the leave is taken and are measured at the rate paid or payable. ii. Long service leave The liability for long service leave is recognized in the provision for employee benefits and measured as the present value of expected future payments to be made in respect of services provided by employees up to the reporting date. Consideration is given to expected future wage and salary levels, experience of employee departures, and periods of service. Expected future payments are discounted using market yields at the reporting date on bonds with terms to maturity that match, as closely as possible, the estimated future cash outflows.
Share based payment transactions	Share‑based payment transactions The Group provides benefits to directors and employees (including key management personnel) of the Group in the form of share‑based payments, whereby employees render services in exchange for shares or rights over shares (equity‑settled transactions). The cost of these equity‑settled transactions with employees is measured by reference to the fair value at the date at which they are granted. Binomial models are used to value the options issued. The cost of the equity‑settled transactions is recognized, together with a corresponding increase in equity, over the period in which the performance conditions are fulfilled (the vesting period), ending on the date on which the relevant employees become fully entitled to the award (the vesting date). The charge to profit or loss for the period is the cumulative amount less the amounts already charged in previous periods. There is a corresponding credit to equity. Until an award has vested, any amounts recorded are contingent and will be adjusted if more or fewer awards vest than were originally anticipated to do so.
Contributed equity	Contributed equity Ordinary shares are classified as equity. Incremental costs directly attributable to the issue of new shares or options are shown in equity as a deduction, net of tax, from the proceeds.
Revenue recognition	Revenue recognition License revenue in connection with licensing of the Group’s intellectual property (including patents) to customers is recognized as a right to use the Group’s intellectual property as it exists at the point in time in which the license is granted. This is because the contracts for the license of intellectual property are distinct and do not require, nor does the customer reasonably expect, that the Group will undertake further activities that significantly affect the intellectual property to which the customer has the rights. Although the Group is entitled to sales‑based royalties from the eventual sales of goods and services to third parties using the intellectual property licensed, these royalty arrangements do not in themselves indicate that the customer would reasonably expect the Group to undertake such activities, and no such activities are undertaken or contracted in practice. Accordingly, the promise to provide rights to the Group’s intellectual property is accounted for as a performance obligation satisfied at a point in time. The following consideration is received in exchange for licenses of intellectual property: • Up‑front license fees – these are fixed amounts and are recognized at the point in time when the Group transfers the intellectual property to the customer. • Sales‑based royalties – these are variable consideration amounts promised in exchange for the license of intellectual property and are recognized when the sales to third parties occur given the performance obligation to transfer the intellectual property to the customer is already satisfied. During the years ended June 30, 2021, 2020 and 2019, the Group’s only revenue related to sales‑based royalties.
Income tax	Income tax Current tax Current tax assets and liabilities for the current and prior periods are measured at the amount expected to be recovered from or paid to the taxation authorities based on the current period’s taxable income. The tax rates and tax laws used to compute the amount are those that are enacted or substantively enacted by the reporting date. Research and development tax incentive The Research and Development (R&D) Tax Incentive Scheme is an Australian Federal Government program under which eligible companies with annual aggregated revenue of less than A$20 million can receive cash amounts equal to 43.5% of eligible research and development expenditures from the Australian Taxation Office (ATO). The R&D Tax Incentive Scheme incentive relates to eligible expenditure incurred in Australia and, under certain circumstances, overseas on the development of the Group’s lead candidate, OPT‑302. The R&D tax incentive is applied annually to eligible expenditure incurred during the Group’s financial year following annual application to AusIndustry, an Australian governmental agency, and subsequent filing of its Income Tax Return with the ATO after the financial year end. The Group estimates the amount of R&D tax incentive after the completion of the financial year based on eligible Australia and overseas expenditures incurred during that year. The Group has presented incentives in respect of the R&D Tax Incentive Scheme within income tax benefit in the Statement of Profit or Loss and Other Comprehensive Income by analogizing with IAS 12 “Income Taxes”. Deferred tax Deferred income tax is provided on all temporary differences at the reporting date between the tax bases of assets and liabilities and their carrying amounts for financial reporting purposes. Deferred income tax liabilities are recognized for all taxable temporary differences except when the deferred income tax liability arises from the initial recognition of goodwill or of an asset or liability in a transaction that is not a business combination and that, at the time of the transaction, affects neither the accounting profit nor taxable profit or loss. Deferred income tax assets are recognized for all deductible temporary differences, carry forward of unused tax assets (or credits) and unused tax losses, to the extent that it is probable that taxable profit will be available against which the deductible temporary differences, and the carry forward of unused tax credits and unused tax losses can be utilized, except when the deferred income tax asset relating to the deductible temporary differences arises from the initial recognition of an asset or liability in a transaction that is not a business combination and, at the time of the transaction, affects neither the accounting profit or taxable profit or loss. The carrying amount of deferred income tax assets is reviewed at each reporting date and reduced to the extent that it is no longer probable that sufficient taxable profit will be available to allow all or part of the deferred income tax asset to be utilized. Unrecognized deferred income tax assets are reassessed at each reporting date and are recognized to the extent that it has become probable that future taxable profit will allow the deferred tax asset to be recovered. Deferred income tax assets and liabilities are measured at the tax rates that are expected to apply to the year when the asset is realized or the liability is settled, based on tax rates (and tax laws) that have been enacted or substantively enacted at balance date. Income taxes relating to items recognized directly in equity are recognized directly in equity and not in profit or loss.
Tax consolidation legislation	Tax consolidation legislation Tax consolidation is a system adopted by the ATO that treats a group of entities as a single entity for tax purposes. Opthea Limited and its 100% owned Australian domiciled subsidiary formed a tax consolidated group effective July 1, 2003. The head entity, Opthea Limited, and its controlled entity, Vegenics Pty Ltd, are current members of the tax consolidated group and account for their own current and deferred tax amounts. Members of the tax consolidated group have adopted the “separate taxpayer within group” method to allocate the current and deferred tax amounts to each entity within the Group. This method requires adjustments for transactions and events occurring within the tax consolidated group that do not give rise to a tax consequence for the Group or that have a different tax consequence at the level of the Group.
Other taxes	Other taxes Revenues, expenses, assets and liabilities are recognized net of the amount of GST except: • When the GST incurred on a purchase of goods and services is not recoverable from the taxation authority, in which case the GST is recognized as part of the cost of acquisition of the asset or as part of the expense item as applicable; and • Receivables and payables are stated with the amount of GST included. The net amount of GST recoverable from, or payable to the taxation authority is included as part of receivables or payables in the statement of financial position. Cash flows are included in the statement of cash flows on a gross basis and the GST component of cash flows arising from investing and financing activities, which is recoverable from, or payable to, the taxation authority is classified as part of operating cash flows. Commitments and contingencies are disclosed net of the amount of GST recoverable from, or payable to, the taxation authority.

Application of New and Revise_2

Application of New and Revised Accounting Standards (Tables)	12 Months Ended
	Jun. 30, 2021
Disclosure Of Voluntary Change In Accounting Policy [Abstract]
Summary of New and Revised Accounting Standards and Interpretations on Issue But not Yet Effective	At the date of authorization of the financial statements, the Group has not applied the following new and revised International Accounting Standards, Interpretations and amendments that have been issued but are not yet effective: Standard/amendments Effective for annual reporting periods beginning on or after IFRS 1, IAS 12 – Deferred Tax related to Assets and Liabilities arising from a Single Transaction January 1,2023 IAS 8 – Disclosure of Accounting Policies and Definition of Accounting Estimates January 1,2023 IFRS 10 and IAS 28 – Effective Date of Amendments to and – Effective Date of Amendments to and and Editorial Corrections January 1,2023 (Editorial correction apply from January 1, 2018) IAS 1 – Classification of Liabilities as Current or Non-Current January 1,2023 IAS 1 – Classification of Liabilities as Current or Non-Current – Deferral of Effective Date January 1,2023 IFRS 16, IFRS 9, IFRS 1 and IAS 41 – Annual Improvements 2018-2020 and Other Amendments January 1,2023 IFRS 16 Related Rent Concessions beyond 30 June 2021 Amendment to IFRS16 June 1, 2021

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Jun. 30, 2021
Revenue [Abstract]
Summary of Revenue	2021 2020 2019 Restated Restated US$ US$ US$ Revenue 68,613 59,061 112,497 Total Revenue 68,613 59,061 112,497

Other Income (Tables)

Other Income (Tables)	12 Months Ended
	Jun. 30, 2021
Analysis Of Income And Expense [Abstract]
Schedule of Other Income	2021 2020 2019 Restated Restated US$ US$ US$ Finance Income 372,002 480,453 541,034 Grant Income 26,949 41,629 57,235 Total other income 398,951 522,082 598,269

Research and Development Expe_2

Research and Development Expenses (Tables)	12 Months Ended
	Jun. 30, 2021
Disclosure Of Research And Development Expenses [Abstract]
Summary of Research and Development Expenses	2021 2020 2019 Restated Restated US$ US$ US$ Research project costs 25,891,851 12,064,008 22,419,712 Total research and development expenses 25,891,851 12,064,008 22,419,712 (1) The research project costs relate to the research programs in respect to the treatment of eye diseases by OPT‑302.

Expenses (Tables)

Expenses (Tables)	12 Months Ended
	Jun. 30, 2021
Expense By Nature [Abstract]
Summary of Expenses	2021 2020 2019 Restated Restated US$ US$ US$ (a) Administrative expenses Employee benefits expenses: Salaries and fees 1,794,840 1,424,237 1,441,522 Cash bonuses 479,501 193,588 295,626 Superannuation 188,543 141,019 155,218 Share-based payments expense 3,897,638 732,688 685,409 Total employee benefits expense 6,360,522 2,491,532 2,577,775 Other expenses: Insurance 4,419,433 335,786 269,060 Investor relations costs 285,071 254,212 293,313 Audit and accounting 647,549 221,410 98,553 Travel expenses 1,459 44,521 59,994 Payroll tax 18,766 134,845 62,237 Legal fees 83,605 372,431 16,025 Advisory fees 393,843 416,082 — Consultancy costs 367,070 — — Other expenses 714,328 334,262 286,057 Total other expenses 6,931,124 2,113,549 1,085,239 Depreciation of: Equipment and furniture 15,012 14,581 14,194 Leasehold improvements — 344 9,413 Right-of-use assets 91,656 81,611 — Total depreciation expense 106,668 96,536 23,607 Loss on disposal of non-current assets 1,434 1,243 — Total administrative expenses 13,399,748 4,702,860 3,686,621 (b) Occupancy expenses Short term and low value lease expenses — 1,539 56,582 Lease incidental costs 18,445 21,733 21,533 Total occupancy expense 18,445 23,272 78,115

Net Foreign Exchange (Loss)_G_2

Net Foreign Exchange (Loss)/Gain (Tables)	12 Months Ended
	Jun. 30, 2021
Net Foreign Exchange Loss Gain [Abstract]
Summary of Net Foreign Exchange (Loss)/Gain	2021 2020 2019 Restated Restated US$ US$ US$ Net foreign exchange (loss)/gain (11,011,961 ) (265,989 ) 241,814 Total net foreign exchange (loss)/gain (11,011,961 ) (265,989 ) 241,814

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Jun. 30, 2021
Major Components Of Tax Expense Income [Abstract]
Summary of Income Tax Benefit and Current Tax Receivable	2021 2020 2019 Restated Restated US$ US$ US$ (a) Income tax benefit The major components of income tax benefit are: Statement of Profit or Loss and Other Comprehensive Income Current tax Current income tax credit 4,938,846 5,708,767 10,474,432 4,938,846 5,708,767 10,474,432 Deferred tax In respect of the current year — — — Total income tax benefit recognized in the Statement of Comprehensive Income 4,938,846 5,708,767 10,474,432 (b) Current tax receivable June 30, 2021 June 30, 2020 US$ US$ Research and Development Tax Incentive Credit receivable 4,972,898 5,868,152
Summary of Reconciliation Between Income Tax Benefit and the Product of Accounting Loss Before Income Tax Multiplied by the Group’s Applicable Income Tax Rate	A reconciliation between income tax benefit and the product of accounting loss before income tax multiplied by the Group’s applicable income tax rate is as follows: 2021 2020 2019 Restated Restated US$ US$ US$ Accounting loss before tax (50,283,342 ) (16,831,966 ) (25,426,380 ) At the Company's statutory income tax rate of 30% (2020:27.5%, 2019:27.5%) 15,085,003 4,628,791 6,992,255 R&D tax incentive on eligible expenses 4,938,846 5,708,767 10,474,432 Non-deductible R&D expenditure (3,420,951 ) (3,624,766 ) — Other non-deductible expenses - share-based payment expense (1,169,291 ) (201,489 ) — Amount of temporary differences and carried forward tax losses not recognized (10,494,761 ) (802,536 ) (6,992,255 ) 4,938,846 5,708,767 10,474,432
Summary of Recognized Deferred Tax Assets and Liabilities in Statement of Financial Position	(d) Recognized deferred tax assets and liabilities in statement of financial position June 30,2021 June 30, 2020 Deferred income tax at June 30 relates to the following: Deferred tax liabilities: Interest and royalty income receivable (future assessable income) (2,344,514 ) (70,925 ) (2,344,514 ) (70,925 ) Deferred tax assets related to temporary differences: Recognition of tax losses 1,508,764 — Accrued expenses and other liabilities 205,458 303,383 Employee provisions 152,675 128,812 Other miscellaneous items 477,617 430,839 2,344,514 863,034 Less: temporary differences not recognized — (792,109 ) Net deferred tax recognized in the statement of financial position — —

Earnings per Share (Tables)

Earnings per Share (Tables)	12 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Summary of Income Used in Basic and Diluted Earnings Per Share Computation	2021 2020 2019 Restated Restated US$ US$ US$ The following reflects the income used in the basic and diluted earnings per share computations: (a) Earnings used in calculating earnings per share Net loss attributable to ordinary equity holders of the parent (45,344,496 ) (11,123,199 ) (14,951,948 ) (b) Weighted average number of shares Weighted average number of ordinary shares on issue for basic earnings per share 320,432,814 260,795,745 232,795,371 Effect of dilution: Share options — — — Weighted average number of ordinary shares adjusted for the effect of dilution 320,432,814 260,795,745 232,795,371 Loss per share (basic and diluted in cents) (14.15 ) (4.27 ) (6.42 )
Summary of Option Plans	These options related to the following option plans 2021 2020 2019 NED Plan 10,000,000 6,000,000 6,000,000 LTIP 6,644,000 12,044,000 12,969,000 16,644,000 18,044,000 18,969,000

Current Assets _ Cash and Cas_2

Current Assets – Cash and Cash Equivalents (Tables)	12 Months Ended
	Jun. 30, 2021
Current Assets Cash And Cash Equivalents [Abstract]
Summary of Cash and Cash Equivalents	June 30, 2021 June 30, 2020 Restated US$ US$ Cash at bank and in hand 15,538,510 2,077,089 Short-term deposits 102,654,667 40,573,769 Total cash and cash equivalents 118,193,177 42,650,858

Current Assets - Receivables (T

Current Assets - Receivables (Tables)	12 Months Ended
	Jun. 30, 2021
Current Assets Receivables [Abstract]
Summary of Current Assets - Receivables	June 30, 2021 June 30, 2020 Restated US$ US$ Interest receivable 37,905 56,032 GST receivable 1 136,239 105,124 Other receivable 1 391,142 34,417 Total current receivables 565,286 195,573 1 The GST and other receivables are non‑interest bearing. There were no receivables with a material expected credit loss recorded during the financial year (2020: nil).

Current Assets - Prepayments (T

Current Assets - Prepayments (Tables)	12 Months Ended
	Jun. 30, 2021
Current Prepayments [Abstract]
Summary of Current Assets Prepayments	June 30, 2021 June 30, 2020 Restated US$ US$ R&D Contract Research Organization 12,551,398 — Insurance 1,820,059 320,521 Other prepayments 14,698 8,630 Total current prepayments 14,386,155 329,151

Non-Current Assets _ Investme_2

Non-Current Assets – Investments in Financial Assets (Tables)	12 Months Ended
	Jun. 30, 2021
Disclosure Of Financial Instruments [Abstract]
Summary of Investments in Financial Assets	June 30, 2021 June 30, 2020 Restated US$ US$ Listed Australian shares - at fair value 1 — 199,417 — 199,417
Summary of Details of Listed Australian Shares	Listed Investments Ownership interest Fair value at June 2 Exchange on translation Disposal in the financial year 3 Financial value gain/(loss) recognized in OCI 4 Opening fair value 2021 Non-current investments: Optiscan Imaging Limited — — — (669,184 ) 469,767 199,417 Total listed investments — — (669,184 ) 469,767 199,417 2020 (Restated) Non-current investments: Antisense Therapeutics Ltd — (2,469 ) (335,746 ) 174,196 164,019 Optiscan Imaging Limited 1.73 % 199,417 (4,920 ) — (133,098 ) 337,435 Total listed investments 199,417 (7,389 ) (335,746 ) 41,098 501,454 1 These financial assets are investments in equity instruments and are not held for trading, they are held for medium to long‑term strategic purposes. Accordingly, the Group has elected to designate these investments in equity instruments as at FVTOCI as recognizing short‑term fluctuations in these investments’ fair value in profit or loss would not be consistent with the Group’s strategy of holding these investments for long‑term purposes and realizing their performance potential in the long run. 2 The fair value represents the share (bid) price at year end and does not include any capital gains tax or selling costs that may be applicable on the disposal of these investments. These non‑current investments in listed shares consist of investments in ordinary shares, and therefore have no fixed maturity date or coupon rate. 3 During the year ended June 30, 2021, the Group’s investment in Optiscan Imaging Limited (OIL) was sold for net proceeds of US$669,184. The increase in fair value during the year of US$469,767 was recognized in other comprehensive income. The fair value of the investment in OIL at the disposal date was US$669,184. The Group disposed of the investment in line with its Treasury and Investment Policy. During the year ended June 30, 2020, the Group disposed of its remaining investment in Antisense Therapeutics Ltd (ANP) for net proceeds of US$335,746. The increase in fair value during the year of US$174,196 was recognized in other comprehensive income. In accordance with the Group’s accounting policy, the gain remains within the fair value of investments reserve. The fair value of the investment in ANP at the disposal date was US$335,746. The Group disposed of the investment in line with its Treasury and Investments Policy. 4 A fair value increase of US$469,767 (2020: US$41,098) in the carrying value of investments has been made through other comprehensive income in the year due to a net increase in their market value in the year.

Right-of-Use Assets (Tables)

Right-of-Use Assets (Tables)	12 Months Ended
	Jun. 30, 2021
Disclosure Of Quantitative Information About Rightofuse Assets [Abstract]
Summary of Carrying Amount of Lease	The carrying amount of the lease at June 30, 2021 and 2020 is as follows: June 30, 2021 June 30, 2020 Restated US$ US$ Right-of-Use Asset Cost Opening balance as of July 1 251,189 — Additions — 251,189 Exchange on translations 30,365 — 281,554 251,189 Right-of-Use-Asset Depreciation Opening balance as of July 1 (83,729 ) — Charge to the period (91,656 ) (81,611 ) Exchange on translation (12,317 ) (2,118 ) (187,702 ) (83,729 ) Net carrying amount of June 30 93,852 167,460
Summary of Lease Liabilities	June 30, 2021 June 30, 2020 Restated US$ US$ Carrying amount at July 1 182,290 — New lease — 251,189 Payments (69,325 ) (68,899 ) Carrying amount at June 30 112,965 182,290 Maturity analysis: Year 1 124,495 105,026 Year 2 — 87,827 124,495 192,853 Less: unearned interest (11,530 ) (10,563 ) 112,965 182,290 Analyzed into: Current portion 112,965 99,745 Non-current portion — 82,545 112,965 182,290 2021 2020 (1) Restated US$ US$ Amounts recognized in profit or loss: Depreciation expense on right-of-use asset 91,656 81,611 Lease finance costs 5,782 5,148 Expense relating to leases of low value assets 7,042 6,497 104,480 93,256 (1) The adoption of IFRS 16 :Leases which became applicable on July 1, 2019 was reflected in the 2020 year, no expenditure in relation to right-of-use-assets was recognized in the 2019 year .

Non-Current Assets - Prepayme_2

Non-Current Assets - Prepayments (Tables)	12 Months Ended
	Jun. 30, 2021
Disclosure Of Noncurrent Assets Prepayments [Abstract]
Summary of Non-Current Assets - Prepayments	June 30, 2021 June 30, 2020 Restated US$ US$ Insurance 174,541 — Total non-current prepayments 174,541 —

Current Liabilities _ Payables

Current Liabilities – Payables (Tables)	12 Months Ended
	Jun. 30, 2021
Current Liabilities Payables [Abstract]
Summary of Current Liabilities Payables	June 30, 2021 June 30, 2020 Restated US$ US$ Accounts Payable (unsecured) 1 2,417,719 4,014,818 Payroll related tax liability 83,799 39,143 Total current payables 2,501,518 4,053,961 1 Accounts Payable are non‑interest bearing and are normally settled on 30 day terms.

Current Liabilities - Provisi_2

Current Liabilities - Provisions (Tables)	12 Months Ended
	Jun. 30, 2021
Current Provisions [Abstract]
Summary of Current Provisions	June 30, 2021 June 30, 2020 Restated US$ US$ Annual leave 289,043 277,469 Long service leave 202,959 163,296 Total current provisions 492,002 440,765

Non-Current Liabilities - Pro_2

Non-Current Liabilities - Provisions (Tables)	12 Months Ended
	Jun. 30, 2021
Noncurrent Provisions [Abstract]
Summary of Non-Current Liabilities - Provisions	June 30, 2021 June 30, 2020 Restated US$ US$ Long service leave 16,915 27,643 Total non-current provisions 16,915 27,643

Contributed Equity (Tables)

Contributed Equity (Tables)	12 Months Ended
	Jun. 30, 2021
Contributed Equity [Abstract]
Summary of Contributed Equity	June 30, 2021 June 30, 2020 July 1, 2019 Restated Restated US$ US$ US$ (a) Ordinary shares Issued and fully paid at June 30 234,147,526 113,852,364 80,331,016 Movement in ordinary shares: Opening balance 113,852,364 80,331,016 69,788,130 Issue of shares on exercise of quoted options — — 9,069,584 Issue of shares — 33,236,520 — Issue of shares on exercise of options granted under the LTIP — 284,828 — Issue of shares on Nasdaq listing net of issuance cost $10,126,959 105,477,591 — — Issue of shares on exercise of pre-funded warrants net of issuance cost $1,099,412 11,546,029 — — Transfer from option reserve 3,271,542 — 1,473,302 234,147,526 113,852,364 80,331,016 Ordinary shares on issue: No: No: No: Opening balance 269,157,769 249,414,839 202,637,888 Issue of shares on exercise of quoted options — — 46,776,951 Issue of shares — 19,742,930 — Issue of shares on exercise of options granted under the LTIP 5,845,804 — — Issues of shares on Nasdaq listing 68,506,400 — — Issue of share on exercise of pre-funded warrants 7,493,568 — — 351,003,541 269,157,769 249,414,839 June 30, 2021 June 30, 2020 July 1, 2019 Restated Restated US$ US$ US$ (b) Pre-funded warrants Movement in pre-funded warrants: Opening balance — — — Issue of pre-funded warrants in a US initial public offering 12,645,441 — — Cost of issue of pre-funded warrants (1,099,412 ) — — Issue of shares on exercise of pre-funded warrants (11,546,029 ) — — — — — Pre-funded warrants on issue: No: No: No: Opening balance — — — Issue of pre-funded warrants in a US Initial public offering 7,493,600 — — Exercise of pre-funded warrants (7,493,568 ) — — Forfeiture on exercise (32 ) — — — — —

Accumulated Losses and Reserv_2

Accumulated Losses and Reserves (Tables)	12 Months Ended
	Jun. 30, 2021
Disclosure Of Reserves Within Equity [Abstract]
Summary of Accumulated Losses and Reserves	June 30, 2021 June 30, 2020 July 1, 2019 Restated Restated US$ US$ US$ (a) Movements in accumulated losses were as follows: Balance of July 1 (78,779,486 ) (67,656,287 ) (52,704,339 ) Net loss for the period (45,344,496 ) (11,123,199 ) (14,951,948 ) Balance of June 30 (124,123,982 ) (78,779,486 ) (67,656,287 ) (b) Reserves Fair value of Investments reserve (i) 1,085,411 551,409 517,700 Share-based payments reserve (ii) 4,087,650 3,116,080 2,401,769 Foreign translation reserve (iii) 20,089,163 5,827,605 6,257,941 Total reserves 25,262,224 9,495,094 9,177,410 (i) Movement in fair value of investments reserve: Opening balance 551,409 517,700 353,604 Fair value on gains on investments in financial assets 469,767 41,098 181,687 Exchange on translation 64,235 (7,389 ) (17,591 ) Closing balance 1,085,411 551,409 517,700 (ii) Movement in share-based payments reserve: Opening balance 3,116,080 2,401,769 1,816,817 Share-based payments expense 3,897,638 732,688 685,409 Exercise of options (3,271,542 ) (284,828 ) — Exchange on translation 345,474 266,451 (100,457 ) Closing balance 4,087,650 3,116,080 2,401,769 (iii) Movement in foreign translation reserve: Opening balance 5,827,605 6,257,941 7,530,571 (Gains)/loss on translation 14,261,558 (430,336 ) (1,272,630 ) Closing balance 20,089,163 5,827,605 6,257,941 (iv) Movement in option reserve Opening balance — — 1,473,302 Transfer to contributed equity — — (1,473,302 ) Closing balance — — —

Financial Risk Management Obj_2

Financial Risk Management Objectives and Policies (Tables)	12 Months Ended
	Jun. 30, 2021
Interest rate risk [member]
Disclosure Of Risk Management Strategy Related To Hedge Accounting [Line Items]
Summary of Judgments of Reasonably Possible Movements	At June 30, 2021, if interest rates moved, with all variables held constant, post tax (loss)/profit and equity would have been affected as illustrated in the following table: Post tax (loss)/profit impact 2021 2020 2019 Restated Restated US$ US$ US$ Judgments of reasonably possible movements +0.50% (50 basis points) (2020:+0.50%) 359,442 137,676 50,490 -0.50% (50 basis points) (2020:-0.50%) (359,442 ) (137,676 ) (50,490 )
Equity price risk [member]
Disclosure Of Risk Management Strategy Related To Hedge Accounting [Line Items]
Summary of Judgments of Reasonably Possible Movements	At June 30, 2021 and 2020, had the share price moved with all other variables held constant, post tax (loss)/profit and equity would have been affected as illustrated in the table below: 2021 2020 2019 Restated Restated US$ US$ US$ Judgments of reasonably possible movements Impact of loss Impact on equity Impact of loss Impact on equity Impact of loss Impact on equity Change in variables 10% increase in listed share price — — 13,450 13,450 35,102 35,102 10% decrease in listed share price — — (13,450 ) (13,450 ) (35,102 ) (35,102 )
Currency Risk
Disclosure Of Risk Management Strategy Related To Hedge Accounting [Line Items]
Summary of Judgments of Reasonably Possible Movements	At June 30, 2021 and 2020, had the United States dollar (2020: Australian dollar) moved with all other variables held constant, post tax (loss) profit and equity would have been affected as illustrated in the table below: Post tax (loss)/profit impact 2021 2020 2019 Restated Restated US$ US$ US$ Judgments of reasonably possible movements Consolidated AUD/USD +10% (2020:+10%) (2,538,062 ) 219,569 200,257 AUD/USD -10% (2020:-10%) 3,102,076 (268,361 ) (244,759 )
Summary of Exposure to Foreign Currency Risk	The functional currency of the Group changed during the year ended June 30, 2021. Accordingly, the 2021 table illustrates the Group’s exposure to Australian dollars and the 2020 table illustrates the Group’s exposure to US dollars: Consolidated 2021 AUD EURO GBP CAD Financial assets Cash 35,646,457 — — — Receivables 5,513,541 — — — Financial liabilities Payables (1,276,164 ) (41,872 ) (1,290 ) Other financial liabilities — — — — Net exposure 39,883,834 (41,872 ) — (1,290 ) Consolidated 2020 USD EURO GBP CAD Financial assets Cash 42,417 — — — Receivables 25,821 — — — Financial liabilities Payables (3,355,050 ) (10,238 ) (23,481 ) — Other financial liabilities (163,547 ) — — — Net exposure (3,450,359 ) (10,238 ) (23,481 ) —

Related Party Disclosures (Tabl

Related Party Disclosures (Tables)	12 Months Ended
	Jun. 30, 2021
Related Party Transactions [Abstract]
Summary of Consolidated Financial Statements Include Financial Statements of Opthea Limited and Subsidiaries	The consolidated financial statements include the financial statements of Opthea Limited and its subsidiaries in the following table: Parent entity % equity interest 2021 2020 2019 % % % Vegenics Pty Ltd 1 100 100 100 Opthea US Inc 2 100 — — (1) Opthea Limited is the ultimate parent entity. Vegenics Pty Ltd is incorporated in Australia and has the same financial year as Opthea Limited. (2) Opthea Limited is the ultimate parent entity. Opthea US Inc was incorporated in the United States in May 2021 and has the same financial year as Opthea Limited.

Commitments (Tables)

Commitments (Tables)	12 Months Ended
	Jun. 30, 2021
Commitments [Abstract]
Summary of Lease Commitments	Lease commitments are in respect of low value leases which have not been recognized in the Statement of Financial Position. These leases are expensed on a straight‑line basis over the term of the lease. 2021 2020 2019 Restated Restated US$ US$ US$ Within one year 5,304 4,497 4,936 After one year but not more than five years 8,398 11,619 — 13,702 16,116 4,936
Summary of Expenditure Commitments Relating to Services for Clinical Trial and Intellectual Property License Agreements	Expenditure commitments relating to these and intellectual property license agreements are payable as follows: 2021 2020 2019 Restated Restated US$ US$ US$ Within one year 26,377,778 7,660,325 5,460,972 After one year but not more than five years 2,347,060 293,815 60,000 After more than five years — 75,000 90,000 28,724,838 8,029,140 5,610,972

Cash Flow Statement Reconcili_2

Cash Flow Statement Reconciliation (Tables)	12 Months Ended
	Jun. 30, 2021
Cash Flow Statement Reconciliation [Abstract]
Summary of Cash Flow Statement Reconciliation	2021 2020 2019 Restated Restated US$ US$ US$ (a) Reconciliation to cash at the end of the year Cash at bank and in hand (note 14) 118,193,177 42,650,858 15,121,820 118,193,177 42,650,858 15,121,820 (b) Reconciliation of net loss after tax to net cash flows from operations Net loss for the year (45,344,496 ) (11,123,199 ) (14,951,948 ) Adjustments for: Income tax benefit recognized in profit or loss (4,938,846 ) (5,708,767 ) (10,474,432 ) Depreciation of non-current assets 15,012 14,926 23,607 Depreciation of right-of-use assets 91,656 81,611 0 Share-based payments 3,897,638 732,688 685,409 Net exchange differences 11,011,961 265,989 (241,814 ) Changes in: Payables (1,552,443 ) (125,492 ) (1,209,513 ) Receivables (369,712 ) 12,127 83,936 Prepayments (14,231,546 ) (30,994 ) (81,681 ) Provisions 40,510 72,794 26,823 Net cash flows used in operating activities before tax (51,380,266 ) (15,808,317 ) (26,139,613 ) R&D tax incentive received 5,834,099 10,118,697 9,097,526 Net cash flows used in operating activities (45,546,167 ) (5,689,620 ) (17,042,087 ) 2021 2020 2019 Restated Restated US$ US$ US$ (c) Reconciliation of borrowings arising from financing activities Balance at July 1 167,460 — — Non-cash addition 1 — 251,189 — Payment of lease liabilities (87,373 ) (66,781 ) — Exchange on translation 13,765 (16,948 ) — Balance at June 30 93,852 167,460 — 1 Non‑cash addition represents the new lease on the Company’s office premises in Melbourne, Australia that commenced on July 15, 2019.

Key Management Personnel (Table

Key Management Personnel (Tables)	12 Months Ended
	Jun. 30, 2021
Disclosure Of Transactions Between Related Parties [Abstract]
Schedule of Compensation of Key Management Personnel	(a) Compensation of Key Management Personnel 2021 2020 2019 Restated Restated US$ US$ US$ Short-term employee benefits 1,099,081 680,954 715,027 Post-employment benefits 79,550 64,632 67,928 Share-based payments expense 3,897,638 420,751 532,952 5,076,269 1,166,337 1,315,907

Share-Based Payments (Tables)

Share-Based Payments (Tables)	12 Months Ended
	Jun. 30, 2021
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Abstract]
Summary of Recognized Share Based Payment Expenses	The expense recognized for share‑based payments during the year is shown in the table below: 2021 2020 2019 Restated Restated US$ US$ US$ Expense arising from equity-settled share-based payment transactions: Director and employee services received 3,897,638 732,688 685,409 3,897,638 732,688 685,409
Summary of Fair Value of Share Options Granted	Options/Rights services Grant date Grant date fair value US$ Exercise price US$ Expiry date Vesting date LTIP - director FY2016 March 7,2016 0.14 0.36 March 7, 2021 June 30, 2016 LTIP - director FY2019 November 29, 2018 0.15 0.625 November 29, 2022 November 29, 2019 LTIP - employees FY2016 March 31, 2016 0.18 0.37 January 1, 2022 January 1, 2017 LTIP - employees FY2018 August 23, 2017 0.26 0.92 January 1, 2023 June 30, 2018 LTIP - employees FY2019 April 3, 2019 0.18 0.608 April 3, 2023 April 3, 2021 NED Plan FY2016 March 7,2016 0.14 0.36 March 7, 2021 June 30, 2016 NED Plan FY2019 November 29, 2018 0.15 0.625 November 29, 2022 November 29, 2019 NED Plan FY2021 October 12, 2020 1.05 3.24 October 11, 2024 October 12, 2020 NED Plan FY2021 October 12, 2020 1.05 3.24 October 11, 2024 October 12, 2021 NED Plan FY2021 October 12, 2020 1.05 3.24 October 11, 2024 October 12, 2022 NED Plan FY2021 October 12, 2020 1.05 3.24 October 11, 2024 October 12, 2023 NED Plan FY2021 October 12, 2020 1.24 2.16 October 11, 2024 October 12, 2020 NED Plan FY2021 October 12, 2020 1.24 2.16 October 11, 2024 October 12, 2021 NED Plan FY2021 October 12, 2020 1.24 2.16 October 11, 2024 October 12, 2022 NED Plan FY2021 October 12, 2020 1.24 2.16 October 11, 2024 October 12, 2023 NED Plan FY2021 January 19, 2021 0.88 1.56 January 18, 2025 January 19, 2021 NED Plan FY2021 January 19, 2021 0.88 1.56 January 18, 2025 January 19, 2022 NED Plan FY2021 January 19, 2021 0.88 1.56 January 18, 2025 January 19, 2023 NED Plan FY2021 January 19, 2021 0.88 1.56 January 18, 2025 January 19, 2024 Options/Rights services Grant date share price US$ Exercise price US$ Fair value per option US$ Expected volatility Option life Dividend yield Risk free interest rate Model used LTIP - director FY2016 0.28 0.36 0.14 65 % 5 years 0 % 2.09 % Binomial LTIP - director FY2019 0.42 0.63 0.15 58 % 4 years 0 % 2.04 % Binomial LTIP - employees FY2016 0.54 0.37 0.18 65 % 5 years 0 % 2.09 % Binomial LTIP - employees FY2018 0.34 0.92 0.26 66 % 5 years 0 % 2.09 % Binomial LTIP - employees FY2019 0.48 0.61 0.18 57 % 4 years 0 % 2.04 % Binomial NED Plan FY2016 0.28 0.36 0.14 65 % 5 years 0 % 2.09 % Binomial NED Plan FY2019 0.42 0.63 0.15 58 % 4 years 0 % 2.04 % Binomial NED Plan FY2021 2.19 2.16 1.24 77.25 % 4 years 0 % 0.25 % Binomial NED Play FY2021 2.19 3.24 1.05 77.25 % 4 years 0 % 0.25 % Binomial NED Plan FY2021 1.56 1.56 0.88 77.01 % 4 years 0 % 0.25 % Binomial
Summary of Share Options Outstanding	The following reconciles the share options outstanding at the beginning and end of the year: 2021 2020 2019 Number of options and rights Weighted average exercise price US$ Number of options and rights Weighted average exercise price US$ Number of options and rights Weighted average exercise price US$ Balance at beginning of year 18,044,000 0.50 18,919,000 0.50 10,075,000 0.39 Granted during the year: To employees and directors under the LTIP and NED Plan 7,000,000 2.21 — — 8,844,000 0.62 Exercised during the year (8,400,000 ) 0.36 (875,000 ) 0.37 — — Expired during the year — — — — — — Balance at end of the year 16,644,000 1.28 18,044,000 0.50 18,919,000 0.50 Exercisable at end of year 11,394,000 0.86 18,044,000 0.50 9,905,000 0.37

Summary of Accounting Policie_2

Summary of Accounting Policies - Additional Information (Details)	12 Months Ended
	Jun. 30, 2021USD ($)AUD ($)	Jun. 30, 2021AUD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Fixed exchange rate	1.2973
Effect on consolidated financial statements resulted in an addition to foreign currency translation reserve	$ 14,300,000
Unsecured amount payable payment period	30 days	30 days
Sales	$ 68,613		$ 59,061	$ 112,497
Percentage of cash amount equal to eligible research and development expenditures	43.50%	43.50%
Australian Domiciled Subsidiary
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Ownership percentage in subsidiary	100.00%	100.00%
Leasehold Improvements
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Useful economic lives	8 years	8 years
Bottom of Range
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Other receivable collection period	30 days	30 days
Bottom of Range | Equipment and Furniture
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Useful economic lives	3 years	3 years
Top of Range
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Other receivable collection period	60 days	60 days
Top of Range | Research and Development Tax Incentive Scheme
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Sales		$ 20,000,000
Top of Range | Equipment and Furniture
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Useful economic lives	10 years	10 years

Critical Accounting Judgement_2

Critical Accounting Judgements and Key Sources of Estimation Uncertainty - Additional Information (Details)	12 Months Ended
	Jun. 30, 2021USD ($)	Jun. 30, 2021AUD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)
Critical Accounting Judgements And Key Sources Of Estimation Uncertainty [Line Items]
Research and development expense	$ 25,891,851		$ 12,064,008	$ 22,419,712
Percentage of cash amount equal to eligible research and development expenditures	43.50%	43.50%
Research and development tax incentive credit receivable	$ 4,972,898		5,868,152	5,900,000
Research and development tax incentive description	The R&D tax incentive is considered an income tax offset which will be offset against the Group’s tax obligation if and when the Group returns to a net tax payable position. In addition, whilst the Group is currently eligible to receive cash payments under the scheme since its consolidated revenue is currently below A$20 million, if and when the Group generates revenue in excess of A$20 million the R&D tax incentive will become non‑refundable and can only be offset against any future income tax payable by the Group.	The R&D tax incentive is considered an income tax offset which will be offset against the Group’s tax obligation if and when the Group returns to a net tax payable position. In addition, whilst the Group is currently eligible to receive cash payments under the scheme since its consolidated revenue is currently below A$20 million, if and when the Group generates revenue in excess of A$20 million the R&D tax incentive will become non‑refundable and can only be offset against any future income tax payable by the Group.
Revenue	$ 68,613		59,061	112,497
Research and Development Tax Incentive Scheme | Top of Range
Critical Accounting Judgements And Key Sources Of Estimation Uncertainty [Line Items]
Revenue		$ 20,000,000
Research and Development Tax Incentive Scheme | Bottom of Range | Non Refundable
Critical Accounting Judgements And Key Sources Of Estimation Uncertainty [Line Items]
Revenue		$ 20,000,000
Development Cost Capitalized
Critical Accounting Judgements And Key Sources Of Estimation Uncertainty [Line Items]
Research and development expense	$ 0		$ 0	$ 0

Application of New and Revise_3

Application of New and Revised Accounting Standards - Summary of New and Revised Accounting Standards and Interpretations on Issue But not Yet Effective (Details)	12 Months Ended
	Jun. 30, 2021
IFRS 1, IAS 12– Deferred Tax related to Assets and Liabilities arising from a Single Transaction
Disclosure Of Voluntary Change In Accounting Policy [Line Items]
Effective for annual reporting periods beginning on or after	Jan. 1, 2023
IAS 8– Disclosure of Accounting Policies and Definition of Accounting Estimates
Disclosure Of Voluntary Change In Accounting Policy [Line Items]
Effective for annual reporting periods beginning on or after	Jan. 1, 2023
IFRS 10 and IAS 28 – Effective Date of Amendments to IFRS 10 and IAS 28– Effective Date of Amendments to IFRS 10 and IAS 28 and Editorial Corrections
Disclosure Of Voluntary Change In Accounting Policy [Line Items]
Effective for annual reporting periods beginning on or after	Jan. 1, 2023
IAS 1 – Classification of Liabilities as Current or Non-Current
Disclosure Of Voluntary Change In Accounting Policy [Line Items]
Effective for annual reporting periods beginning on or after	Jan. 1, 2023
IAS 1– Classification of Liabilities as Current or Non-Current – Deferral of Effective Date
Disclosure Of Voluntary Change In Accounting Policy [Line Items]
Effective for annual reporting periods beginning on or after	Jan. 1, 2023
IFRS 16, IFRS 9, IFRS 1 and IAS 41 – Annual Improvements 2018-2020 and Other Amendments
Disclosure Of Voluntary Change In Accounting Policy [Line Items]
Effective for annual reporting periods beginning on or after	Jan. 1, 2023
IFRS 16 Related Rent Concessions beyond 30 June 2021 Amendment to IFRS16
Disclosure Of Voluntary Change In Accounting Policy [Line Items]
Effective for annual reporting periods beginning on or after	Jun. 1, 2021

Segment Information - Additiona

Segment Information - Additional Information (Details)	12 Months Ended
	Jun. 30, 2021USD ($)IndustryGeographicalareaSegment	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)
Disclosure Of Operating Segments [Abstract]
Number of operating segment | Industry	1
Number of geographical area | Geographicalarea	1
Number of reporting segment | Segment	1
Royalty income | $	$ 68,613	$ 59,061	$ 112,497

Revenue - Summary of Revenue (D

Revenue - Summary of Revenue (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Revenue [Abstract]
Revenue	$ 68,613	$ 59,061	$ 112,497

Other Income - Schedule of Othe

Other Income - Schedule of Other Income (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Analysis Of Income And Expense [Abstract]
Finance Income	$ 372,002	$ 480,453	$ 541,034
Grant Income	26,949	41,629	57,235
Total other income	$ 398,951	$ 522,082	$ 598,269

Research and Development Expe_3

Research and Development Expenses - Summary of Research and Development Expenses (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Disclosure Of Research And Development Expenses [Abstract]
Research project costs	$ 25,891,851	$ 12,064,008	$ 22,419,712
Total research and development expenses	$ 25,891,851	$ 12,064,008	$ 22,419,712

Expenses - Summary of Expenses

Expenses - Summary of Expenses (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020		Jun. 30, 2019
Employee benefits expenses:
Salaries and fees	$ 1,794,840	$ 1,424,237		$ 1,441,522
Cash bonuses	479,501	193,588		295,626
Superannuation	188,543	141,019		155,218
Share-based payments expense	3,897,638	732,688		685,409
Total employee benefits expense	6,360,522	2,491,532		2,577,775
Other expenses:
Insurance	4,419,433	335,786		269,060
Investor relations costs	285,071	254,212		293,313
Audit and accounting	647,549	221,410		98,553
Travel expenses	1,459	44,521		59,994
Payroll tax	18,766	134,845		62,237
Legal fees	83,605	372,431		16,025
Advisory fees	393,843	416,082
Consultancy costs	367,070
Other expenses	714,328	334,262		286,057
Total other expenses	6,931,124	2,113,549		1,085,239
Depreciation of:
Equipment and furniture	15,012	14,581		14,194
Leasehold improvements		344		9,413
Right-of-use assets	91,656	81,611	[1]
Total depreciation expense	106,668	96,536		23,607
Loss on disposal of non-current assets	1,434	1,243
Total administrative expenses	13,399,748	4,702,860		3,686,621
(b) Occupancy expenses
Short term and low value lease expenses		1,539		56,582
Lease incidental costs	18,445	21,733		21,533
Total occupancy expense	$ 18,445	$ 23,272		$ 78,115
[1]	The adoption of IFRS 16 :Leases which became applicable on July 1, 2019 was reflected in the 2020 year, no expenditure in relation to right-of-use-assets was recognized in the 2019 year .

Net Foreign Exchange (Loss)_G_3

Net Foreign Exchange (Loss)/Gain - Summary of Net Foreign Exchange (Loss)/Gain (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Net Foreign Exchange Loss Gain [Abstract]
Net foreign exchange (loss)/gain	$ (11,011,961)	$ (265,989)	$ 241,814
Net foreign exchange gain/(loss)	$ (11,011,961)	$ (265,989)	$ 241,814

Net Foreign Exchange (Loss)_G_4

Net Foreign Exchange (Loss)/Gain - Additional Information (Details) $ in Thousands, $ in Millions	12 Months Ended
	Jun. 30, 2021USD ($)	Jun. 30, 2021AUD ($)	Feb. 03, 2021USD ($)	Feb. 03, 2021AUD ($)
Net Foreign Exchange Loss Gain [Line Items]
Term deposit	$ 100	$ 141,900	$ 100	$ 116
Term deposit maturity date	Feb. 3, 2021
Foreign exchange loss	$ 9
US IPO
Net Foreign Exchange Loss Gain [Line Items]
Aggregate gross proceeds for IPO	$ 128

Income Taxes - Summary of Incom

Income Taxes - Summary of Income Tax Benefit and Current Tax Receivable (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Current tax
Current income tax credit	$ 4,938,846	$ 5,708,767	$ 10,474,432
Total	4,938,846	5,708,767	10,474,432
Deferred tax
Total income tax benefit recognized in the Statement of Comprehensive Income	4,938,846	5,708,767	10,474,432
(b) Current tax receivable
Research and development tax incentive credit receivable	$ 4,972,898	$ 5,868,152	$ 5,900,000

Income Taxes - Summary of Recon

Income Taxes - Summary of Reconciliation Between Income Tax Benefit and the Product of Accounting Loss Before Income Tax Multiplied by the Group's Applicable Income Tax Rate (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Reconciliation Of Accounting Profit Multiplied By Applicable Tax Rates [Abstract]
Accounting loss before tax	$ (50,283,342)	$ (16,831,966)	$ (25,426,380)
At the Company's statutory income tax rate of 30% (2020:27.5%, 2019:27.5%)	15,085,003	4,628,791	6,992,255
R&D tax incentive on eligible expenses	4,938,846	5,708,767	10,474,432
Non-deductible R&D expenditure	(3,420,951)	(3,624,766)
Other non-deductible expenses - share-based payment expense	(1,169,291)	(201,489)
Amount of temporary differences and carried forward tax losses not recognized	(10,494,761)	(802,536)	(6,992,255)
Total income tax benefit recognized in the Statement of Comprehensive Income	$ 4,938,846	$ 5,708,767	$ 10,474,432

Income Taxes - Summary of Rec_2

Income Taxes - Summary of Reconciliation Between Income Tax Benefit and the Product of Accounting Loss Before Income Tax Multiplied by the Group's Applicable Income Tax Rate (Parenthetical) (Details)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Reconciliation Of Accounting Profit Multiplied By Applicable Tax Rates [Abstract]
Income tax rate	30.00%	27.50%	27.50%

Income Taxes - Summary of Recog

Income Taxes - Summary of Recognized Deferred Tax Assets and Liabilities in Statement of Financial Position (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Deferred tax liabilities:
Deferred tax liabilities	$ (2,344,514)	$ (70,925)
Deferred tax assets related to temporary differences:
Deferred tax assets related to temporary differences	2,344,514	863,034
Less: temporary differences not recognized		(792,109)
Net deferred tax recognized in the statement of financial position	0	0
Interest and Royalty Income Receivable Future Assessable Income
Deferred tax liabilities:
Deferred tax liabilities	(2,344,514)	(70,925)
Recognition of Tax Losses
Deferred tax assets related to temporary differences:
Deferred tax assets related to temporary differences	1,508,764
Accrued Expenses and Other Liabilities
Deferred tax assets related to temporary differences:
Deferred tax assets related to temporary differences	205,458	303,383
Employee Provisions
Deferred tax assets related to temporary differences:
Deferred tax assets related to temporary differences	152,675	128,812
Other Miscellaneous Items
Deferred tax assets related to temporary differences:
Deferred tax assets related to temporary differences	$ 477,617	$ 430,839

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details)	12 Months Ended
	Jun. 30, 2021USD ($)	Jun. 30, 2021AUD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2020AUD ($)
Disclosure Of Temporary Difference Unused Tax Losses And Unused Tax Credits [Line Items]
Deferred tax assets related to temporary differences not recognized			$ (792,109)
Income tax losses	$ 20,846,641		14,378,726
Capital losses	672,934		672,934
Net deferred tax recognized in the statement of financial position	$ 0		$ 0
Franking account balance percentage	30.00%	30.00%	30.00%	30.00%
Franking account balance		$ 227,371		$ 227,371
Intellectual Property and Other Miscellaneous Items
Disclosure Of Temporary Difference Unused Tax Losses And Unused Tax Credits [Line Items]
Deferred tax assets related to temporary differences not recognized			$ 792,109

Earnings Per Share - Summary of

Earnings Per Share - Summary of Income Used in Basic and Diluted Earnings Per Share Computation (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
(a) Earnings used in calculating earnings per share
Net loss attributable to ordinary equity holders of the parent	$ (45,344,496)	$ (11,123,199)	$ (14,951,948)
(b) Weighted average number of shares
Weighted average number of ordinary shares on issue for basic earnings per share	320,432,814	260,795,745	232,795,371
Effect of dilution:
Weighted average number of ordinary shares adjusted for the effect of dilution	320,432,814	260,795,745	232,795,371
Loss per share (basic and diluted in cents)	$ (14.15)	$ (4.27)	$ (6.42)

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Details)	12 Months Ended
	Jun. 30, 2021USD ($)shares	Jun. 30, 2020shares	Jun. 30, 2019shares
Earnings Per Share [Abstract]
Anti‑dilutive options outstanding excluded from the weighted average number of ordinary shares for the purpose of diluted earnings per share | shares	16,644,000	18,044,000	18,969,000
Dividends declared ordinary shares | $	$ 0
Dividends paid ordinary shares | $	$ 0
Outstanding options exercisable | shares	11,394,000	18,044,000	9,905,000

Earnings Per Share - Summary _2

Earnings Per Share - Summary of Options Plans (Details) - shares	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Line Items]
Anti‑dilutive options outstanding excluded from the weighted average number of ordinary shares for the purpose of diluted earnings per share	16,644,000	18,044,000	18,969,000
NED Plan
Earnings Per Share [Line Items]
Anti‑dilutive options outstanding excluded from the weighted average number of ordinary shares for the purpose of diluted earnings per share	10,000,000	6,000,000	6,000,000
LTIP
Earnings Per Share [Line Items]
Anti‑dilutive options outstanding excluded from the weighted average number of ordinary shares for the purpose of diluted earnings per share	6,644,000	12,044,000	12,969,000

Current Assets - Cash and Cash

Current Assets - Cash and Cash Equivalents - Summary of Cash and Cash Equivalents (Details) - USD ($)	Jun. 30, 2021	Jun. 30, 2020	Jul. 01, 2019	Jun. 30, 2019	Jun. 30, 2018
Categories Of Current Financial Assets [Abstract]
Cash at bank and in hand	$ 15,538,510	$ 2,077,089
Short-term deposits	102,654,667	40,573,769
Total cash and cash equivalents	$ 118,193,177	$ 42,650,858	$ 15,121,820	$ 15,121,820	$ 24,080,327

Current Assets - Cash and Cas_2

Current Assets - Cash and Cash Equivalents - Additional Information (Details) - Deposit	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Current Assets Cash And Cash Equivalents [Line Items]
Number of Australian banks containing short term deposit	2
Average interest rate of short term deposits	0.24%	1.01%
Bottom of Range
Current Assets Cash And Cash Equivalents [Line Items]
Short term deposit period	30 days
Top of Range
Current Assets Cash And Cash Equivalents [Line Items]
Short term deposit period	90 days

Current Assets - Receivables -

Current Assets - Receivables - Summary of Current Assets - Receivables (Details) - USD ($)	Jun. 30, 2021	Jun. 30, 2020	Jul. 01, 2019
Current Assets Receivables [Abstract]
Interest receivable	$ 37,905	$ 56,032
GST receivable	136,239	105,124
Other receivable	391,142	34,417
Total current receivables	$ 565,286	$ 195,573	$ 207,701

Current Assets - Receivables _2

Current Assets - Receivables - Summary of Current Assets - Receivables (Parenthetical) (Details)	Jun. 30, 2021USD ($)
Current Assets Receivables [Abstract]
Receivables with material expected credit loss	$ 0

Current Assets - Prepayments -

Current Assets - Prepayments - Summary of Current Assets Prepayments (Details) - USD ($)	Jun. 30, 2021	Jun. 30, 2020	Jul. 01, 2019
Current Prepayments [Abstract]
R&D Contract Research Organization	$ 12,551,398
Insurance	1,820,059	$ 320,521
Other prepayments	14,698	8,630
Total current prepayments	$ 14,386,155	$ 329,151	$ 298,156

Non-Current Assets - Investment

Non-Current Assets - Investments in Financial Assets - Summary of Investments in Financial Assets (Details)	Jun. 30, 2020USD ($)
Disclosure Of Financial Instruments [Line Items]
Listed Australian shares - at fair value1	$ 199,417
Listed Australian shares
Disclosure Of Financial Instruments [Line Items]
Listed Australian shares - at fair value1	$ 199,417

Non-Current Assets - Investme_2

Non-Current Assets - Investments in Financial Assets - Summary of Details of Listed Australian Shares (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Disclosure Of Financial Instruments [Line Items]
Fair value		$ 199,417
Opening fair value	$ 199,417
Listed Investments
Disclosure Of Financial Instruments [Line Items]
Fair value		199,417
Exchange on translation		(7,389)
Disposal in the financial year	(669,184)	(335,746)
Financial value gain/(loss) recognized in OCI	469,767	41,098
Opening fair value	199,417	$ 501,454
Listed Investments | Optiscan Imaging Limited
Disclosure Of Financial Instruments [Line Items]
Ownership interest		1.73%
Fair value		$ 199,417
Exchange on translation		(4,920)
Disposal in the financial year	(669,184)
Financial value gain/(loss) recognized in OCI	469,767	(133,098)
Opening fair value	$ 199,417	337,435
Listed Investments | Antisense Therapeutics Ltd
Disclosure Of Financial Instruments [Line Items]
Exchange on translation		(2,469)
Disposal in the financial year		(335,746)
Financial value gain/(loss) recognized in OCI		174,196
Opening fair value		$ 164,019

Non-Current Assets - Investme_3

Non-Current Assets - Investments in Financial Assets - Summary of Details of Listed Australian Shares (Parenthetical) (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Disclosure Of Financial Instruments [Line Items]
Fair value recognized in other comprehensive income	$ 469,767	$ 41,098
Optiscan Imaging Limited
Disclosure Of Financial Instruments [Line Items]
Net proceeds of sale	669,184
Fair value recognized in other comprehensive income	469,767
Fair value of investment	$ 669,184
Antisense Therapeutics Ltd
Disclosure Of Financial Instruments [Line Items]
Net proceeds of sale		335,746
Fair value recognized in other comprehensive income		174,196
Fair value of investment		$ 335,746

Right-of-Use Assets - Summary o

Right-of-Use Assets - Summary of Carrying Amount of Lease (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Disclosure Of Quantitative Information About Rightofuse Assets [Line Items]
Opening balance	$ 167,460
Net carrying amount	93,852	$ 167,460
Right-of-Use Asset Cost
Disclosure Of Quantitative Information About Rightofuse Assets [Line Items]
Opening balance	251,189
Additions		251,189
Exchange on translations	30,365
Net carrying amount	281,554	251,189
Right-of-Use-Asset Depreciation
Disclosure Of Quantitative Information About Rightofuse Assets [Line Items]
Opening balance	(83,729)
Charge to the period	(91,656)	(81,611)
Exchange on translation	(12,317)	(2,118)
Net carrying amount	$ (187,702)	$ (83,729)

Right-of-Use Assets - Additiona

Right-of-Use Assets - Additional information (Details)	12 Months Ended
	Jun. 30, 2021
Disclosure Of Quantitative Information About Rightofuse Assets [Abstract]
Lease liabilities term	Jul. 14, 2022
Incremental borrowing rate	3.00%

Right-of-Use Assets - Lease Lia

Right-of-Use Assets - Lease Liabilities (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Lease Liabilities [Abstract]
Carrying amount at July 1	$ 182,290	$ 182,290
New lease		251,189
Payments	(69,325)	(68,899)
Carrying amount at June 30	112,965	182,290
Maturity analysis year 1	124,495	105,026
Maturity analysis year 2		87,827
Maturity analysis	124,495	192,853
Less: unearned interest	(11,530)	(10,563)
Lease liabilities maturity analysis, Net	112,965	182,290
Current portion	112,965	99,745
Non-current portion		82,545
Lease liabilities	112,965	182,290
Amounts recognized in profit or loss:
Depreciation expense on right-of-use asset	91,656	81,611	[1]
Lease finance costs	5,782	5,148	[1]
Expense relating to leases of low value assets	7,042	6,497	[1]
Lease liability amounts recognized in profit and loss	$ 104,480	$ 93,256	[1]
[1]	The adoption of IFRS 16 :Leases which became applicable on July 1, 2019 was reflected in the 2020 year, no expenditure in relation to right-of-use-assets was recognized in the 2019 year .

Right-of-Use Assets - Lease L_2

Right-of-Use Assets - Lease Liabilities (Parenthetical) (Details)	12 Months Ended
	Jun. 30, 2019USD ($)
IFRS 16
Disclosure Of Lease Liabilities [Line Items]
Expenditure in relation to right-of-use-assets recognized	$ 0

Non-Current Assets - Prepayme_3

Non-Current Assets - Prepayments - Summary of Non-Current Assets - Prepayments (Details)	Jun. 30, 2021USD ($)
Disclosure Of Noncurrent Assets Prepayments [Abstract]
Insurance	$ 174,541
Total non-current prepayments	$ 174,541

Current Liabilities - Payables

Current Liabilities - Payables - Summary of Current Liabilities Payables (Details) - USD ($)	Jun. 30, 2021	Jun. 30, 2020
Current Liabilities Payables [Abstract]
Accounts Payable (unsecured)	$ 2,417,719	$ 4,014,818
Payroll related tax liability	83,799	39,143
Total current payables	$ 2,501,518	$ 4,053,961

Current Liabilities - Payable_2

Current Liabilities - Payables - Summary of Current Liabilities Payables (Parenthetical) (Details)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Current Liabilities Payables [Abstract]
Accounts payable settlement terms	30 day terms	30 day terms

Current Liabilities - Provisi_3

Current Liabilities - Provisions - Summary of Current Provisions (Details) - USD ($)	Jun. 30, 2021	Jun. 30, 2020	Jul. 01, 2019
Current Provisions [Abstract]
Annual leave	$ 289,043	$ 277,469
Long service leave	202,959	163,296
Total current provisions	$ 492,002	$ 440,765	$ 378,168

Non-Current Liabilities - Pro_3

Non-Current Liabilities - Provisions - Summary of Non-Current Liabilities - Provisions (Details) - USD ($)	Jun. 30, 2021	Jun. 30, 2020	Jul. 01, 2019
Noncurrent Provisions [Abstract]
Long service leave	$ 16,915	$ 27,643
Total non-current provisions	$ 16,915	$ 27,643	$ 17,445

Contributed Equity - Summary of

Contributed Equity - Summary of Contributed Equity (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019	Jul. 01, 2019
Contributed Equity [Line Items]
Issued and fully paid at June 30	$ 234,147,526	$ 113,852,364		$ 80,331,016
Movement in ordinary shares:
Beginning balance	44,567,972	21,852,139	$ 28,258,085
Ending balance	$ 135,285,768	44,567,972	21,852,139
Issues of shares on Nasdaq listing	68,506,400
Movement in pre-funded warrants:
Issue of shares on exercise of pre-funded warrants	$ (11,546,029)
Issue of pre-funded warrants in a US Initial public offering	7,493,600
Ordinary Shares
Contributed Equity [Line Items]
Issued and fully paid at June 30	$ 234,147,526	113,852,364	80,331,016
Movement in ordinary shares:
Beginning balance	113,852,364	80,331,016	69,788,130
Issue of shares on exercise of quoted options			9,069,584
Issue of shares		33,236,520
Issue of shares on exercise of options granted under the LTIP		284,828
Issue of shares on Nasdaq listing net of issuance cost $10,126,959	105,477,591
Issue of shares on exercise of pre-funded warrants net of issuance cost $1,099,412	11,546,029
Transfer from option reserve	3,271,542		1,473,302
Ending balance	$ 234,147,526	$ 113,852,364	$ 80,331,016
Ordinary Shares on Issue
Movement in ordinary shares:
Opening balance	269,157,769	249,414,839	202,637,888
Issue of shares on exercise of quoted options			46,776,951
Issue of shares		19,742,930
Issue of shares on exercise of options granted under the LTIP	5,845,804
Issues of shares on Nasdaq listing	68,506,400
Issue of share on exercise of pre-funded warrants	7,493,568
Ending balance	351,003,541	269,157,769	249,414,839
Pre-funded Warrants
Movement in pre-funded warrants:
Issue of pre-funded warrants in a US initial public offering	$ 12,645,441
Cost of issue of pre-funded warrants	(1,099,412)
Issue of shares on exercise of pre-funded warrants	$ (11,546,029)
Pre-Funded Warrants on Issue
Movement in pre-funded warrants:
Issue of pre-funded warrants in a US Initial public offering	7,493,600
Exercise of pre-funded warrants	(7,493,568)
Forfeiture on exercise	(32)

Contributed Equity - Summary _2

Contributed Equity - Summary of Contributed Equity (Parenthetical) (Details)	12 Months Ended
	Jun. 30, 2021USD ($)
NASDAQ Listing
Contributed Equity [Line Items]
Shares issuance cost	$ 10,126,959
Exercise of Warrants
Contributed Equity [Line Items]
Shares issuance cost	$ 1,099,412

Contributed Equity - Additional

Contributed Equity - Additional Information (Details)	1 Months Ended		12 Months Ended
	Jun. 30, 2021USD ($)$ / sharesshares	Mar. 31, 2021shares	Jun. 30, 2021USD ($)sharesVoteScheme$ / shares	Jun. 30, 2020USD ($)shares	Jun. 30, 2019shares	Jul. 01, 2019USD ($)
Contributed Equity [Line Items]
Par value per share | $ / shares	$ 0		$ 0
Number of vote per share | Vote			1
Issued and fully paid at June 30 | $	$ 234,147,526		$ 234,147,526	$ 113,852,364		$ 80,331,016
Fully paid ordinary shares	351,003,541		351,003,541
Shares issued on NASDAQ Listing			68,506,400
Net proceeds from issuance of ordinary shares on Nasdaq listing | $			$ 105,477,591
Issuance of prefunded warrants			7,493,568
Net proceeds from issuance of prefunded warrants | $			$ 11,546,029
Number of non-executive director options unexercised	6,750,000		6,750,000
Number of share based payment schemes | Scheme			2
Number of options granted			7,000,000		8,844,000
Cash received for ordinary shares issued on exercise of options | $				$ 284,828
Issue of pre-funded warrants in initial public offering			7,493,600
Issue of shares on exercise of pre-funded warrants value, net of issuance cost | $			$ 11,546,029
Warrants exercise price | $ / shares			$ 0.00001
Pre-funded warrants description			The pre‑funded warrants were unquoted, having no voting or dividend rights and are exercisable to ADS’s at an exercise price of US$0.00001 per pre‑funded warrant on a one for one basis with no expiry date. During the year all pre‑funded warrants that were issued October 20, 2020 were exercised via two trenches, 4,147,136 warrants in March 2021 and 3,346,432 warrants in June 2021 converted to ADS’s.
Number of pre-funded warrants exercised	3,346,432	4,147,136
Options Over Ordinary Shares
Contributed Equity [Line Items]
Number of options granted			7,000,000	0
Weighted average fair value per option at grant date | $ / shares			$ 1.03
LTIP and NED Plan
Contributed Equity [Line Items]
Number of options granted			8,400,000	0
Cash received for ordinary shares issued on exercise of options | $			$ 3,271,542
Expiry of November 2022
Contributed Equity [Line Items]
Number of non-executive director options unexercised	1,500,000		1,500,000
Expiry of October 2023
Contributed Equity [Line Items]
Number of non-executive director options unexercised	3,000,000		3,000,000
Expiry of January 2024
Contributed Equity [Line Items]
Number of non-executive director options unexercised	2,250,000		2,250,000

Accumulated Losses and Reserv_3

Accumulated Losses and Reserves - Summary of Accumulated Losses and Reserves (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019	Jul. 01, 2019	Nov. 25, 2018
Disclosure Of Reserves Within Equity [Line Items]
Net loss for the period	$ (45,344,496)	$ (11,123,199)	$ (14,951,948)
Total reserves	25,262,224	9,495,094		$ 9,177,410
Exchange on translation	14,300,000
Movements in Accumulated Losses
Disclosure Of Reserves Within Equity [Line Items]
Beginning balance	(78,779,486)	(67,656,287)	(52,704,339)
Net loss for the period	(45,344,496)	(11,123,199)	(14,951,948)
Ending balance	(124,123,982)	(78,779,486)	(67,656,287)
Reserves
Disclosure Of Reserves Within Equity [Line Items]
Fair value of Investments reserve	1,085,411	551,409	517,700
Share-based payments reserve	4,087,650	3,116,080	2,401,769
Foreign translation reserve	20,089,163	5,827,605	6,257,941
Total reserves	25,262,224	9,495,094	9,177,410
Movement in Fair Value of Investments Reserve
Disclosure Of Reserves Within Equity [Line Items]
Opening balance	551,409	517,700	353,604
Fair value on gains on investments in financial assets	469,767	41,098	181,687
Exchange on translation	64,235	(7,389)	(17,591)
Closing balance	1,085,411	551,409	517,700
Movement in Share-Based Payments Reserve
Disclosure Of Reserves Within Equity [Line Items]
Opening balance	3,116,080	2,401,769	1,816,817
Share-based payments reserve	3,897,638	732,688	685,409
Exercise of options	(3,271,542)	(284,828)
Exchange on translation	345,474	266,451	(100,457)
Closing balance	4,087,650	3,116,080	2,401,769
FX Translation Reserve
Disclosure Of Reserves Within Equity [Line Items]
Opening balance	5,827,605	6,257,941	7,530,571
(Gains)/loss on translation	14,261,558	(430,336)	(1,272,630)
Closing balance	20,089,163	5,827,605	6,257,941
Movement in Option Reserve
Disclosure Of Reserves Within Equity [Line Items]
Opening balance	0	0	1,473,302
Transfer to contributed equity			(1,473,302)		$ 1,473,302
Closing balance	$ 0	$ 0	$ 0

Accumulated Losses and Reserv_4

Accumulated Losses and Reserves - Additional Information (Details) - Movement in Option Reserve - USD ($)	Nov. 25, 2014	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019	Nov. 25, 2018	Jun. 30, 2018
Disclosure Of Reserves Within Equity [Line Items]
Options to purchase of ordinary shares issued	$ 49,726,672
Exercise price of ordinary shares issued	$ 0.19
Option reserve expiration date	Nov. 25, 2018
Option reserve	$ 1,473,302	$ 0	$ 0	$ 0		$ 1,473,302
Transfer to contributed equity				$ (1,473,302)	$ 1,473,302

Financial Risk Management Obj_3

Financial Risk Management Objectives and Policies - Summary of Judgments of Reasonably Possible Movements (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
+0.50% (50 basis points) (2020:+0.50%) | Post tax (loss)/profit impact [Member]
Disclosure Of Risk Management Strategy Related To Hedge Accounting [Line Items]
Judgments of reasonably possible movements	$ 359,442	$ 137,676	$ 50,490
-0.50% (50 basis points) (2020:-0.50%) | Post tax (loss)/profit impact [Member]
Disclosure Of Risk Management Strategy Related To Hedge Accounting [Line Items]
Judgments of reasonably possible movements	(359,442)	(137,676)	(50,490)
10% Increase in Listed Share Price
Disclosure Of Risk Management Strategy Related To Hedge Accounting [Line Items]
Impact of loss		13,450	35,102
Impact on equity		13,450	35,102
10% Decrease in Listed Share Price
Disclosure Of Risk Management Strategy Related To Hedge Accounting [Line Items]
Impact of loss		(13,450)	(35,102)
Impact on equity		(13,450)	(35,102)
AUD/USD +10% (2020:+10%) | Post tax (loss)/profit impact [Member]
Disclosure Of Risk Management Strategy Related To Hedge Accounting [Line Items]
Judgments of reasonably possible movements	(2,538,062)	219,569	200,257
AUD/USD -10% (2020:-10%) | Post tax (loss)/profit impact [Member]
Disclosure Of Risk Management Strategy Related To Hedge Accounting [Line Items]
Judgments of reasonably possible movements	$ 3,102,076	$ (268,361)	$ (244,759)

Financial Risk Management Obj_4

Financial Risk Management Objectives and Policies - Additional Information (Details) $ in Thousands	12 Months Ended
	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2021AUD ($)	Feb. 03, 2021USD ($)	Feb. 03, 2021AUD ($)
Disclosure Of Risk Management Strategy Related To Hedge Accounting [Line Items]
Borrowings	$ 0
Tax effect	$ 0	$ 0	$ 0
Description of interest rate calculation due to reasonably possible movements	The reasonably possible movement of 0.5% was calculated by taking the interest rates as of balance date, moving these by plus and minus 0.5% and then re‑calculating the interest on term deposits with the ‘new‑interest‑rate’.
Description of calculation of reasonably possible movement related to currency risk	The reasonably possible movement of 10% was calculated by taking the currency spot rates as of balance date, moving these by 10% and then re‑converting the currencies into US with the ‘new‑spot‑rate’.
Proceeds from public offering	$ 128,000,000
Term deposit	$ 100,000,000			$ 141,900	$ 100,000,000	$ 116
Term deposit maturity date	Feb. 3, 2021
Bottom of Range
Disclosure Of Risk Management Strategy Related To Hedge Accounting [Line Items]
Short term deposit period	30 days
Top of Range
Disclosure Of Risk Management Strategy Related To Hedge Accounting [Line Items]
Short term deposit period	90 days

Financial Risk Management Obj_5

Financial Risk Management Objectives and Policies - Summary of Judgments of Reasonably Possible Movements (Parenthetical) (Details)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Disclosure Of Risk Management Strategy Related To Hedge Accounting [Abstract]
Judgments of reasonably possible movements percentage	0.50%	0.50%	0.50%
Judgments of reasonably possible movements change in percentage	10.00%	10.00%	10.00%

Financial Risk Management Obj_6

Financial Risk Management Objectives and Policies - Summary of Exposure to Foreign Currency Risk (Details) - Currency Risk - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
AUD
Financial liabilities
Net exposure	$ 39,883,834	$ (3,450,359)
AUD | Cash
Financial assets
Changes in financial assets due to foreign currency risk exposure	35,646,457	42,417
AUD | Receivables
Financial assets
Changes in financial assets due to foreign currency risk exposure	5,513,541	25,821
AUD | Payables
Financial liabilities
Changes in financial liabilities due to foreign currency risk exposure	(1,276,164)	(3,355,050)
AUD | Other Financial Liabilities
Financial liabilities
Changes in financial liabilities due to foreign currency risk exposure		(163,547)
EUR
Financial liabilities
Net exposure	(41,872)	(10,238)
EUR | Payables
Financial liabilities
Changes in financial liabilities due to foreign currency risk exposure	(41,872)	(10,238)
GBP
Financial liabilities
Net exposure		(23,481)
GBP | Payables
Financial liabilities
Changes in financial liabilities due to foreign currency risk exposure		$ (23,481)
CAD
Financial liabilities
Net exposure	(1,290)
CAD | Payables
Financial liabilities
Changes in financial liabilities due to foreign currency risk exposure	$ (1,290)

Related Party Disclosures - Sum

Related Party Disclosures - Summary of Consolidated Financial Statements Include Financial Statements of Opthea Limited and Subsidiaries (Details)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Vegenics Pty Ltd
Disclosure Of Equity Interest In Subsidiaries [Line Items]
Ownership percentage in subsidiary	100.00%	100.00%	100.00%
Opthea US Inc
Disclosure Of Equity Interest In Subsidiaries [Line Items]
Ownership percentage in subsidiary	100.00%

Commitments - Summary of Lease

Commitments - Summary of Lease Commitments (Details) - USD ($)	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Commitments [Line Items]
Lease commitments	$ 13,702	$ 16,116	$ 4,936
Within One Year
Commitments [Line Items]
Lease commitments	5,304	4,497	$ 4,936
After One Year but not more than Five Years
Commitments [Line Items]
Lease commitments	$ 8,398	$ 11,619

Commitments - Summary of Expend

Commitments - Summary of Expenditure Commitments Relating to Services for Clinical Trial and Intellectual Property License Agreements (Details) - USD ($)	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Commitments [Line Items]
Expenditure commitments relating to services for clinical trial and intellectual property license agreements	$ 28,724,838	$ 8,029,140	$ 5,610,972
Within One Year
Commitments [Line Items]
Expenditure commitments relating to services for clinical trial and intellectual property license agreements	26,377,778	7,660,325	5,460,972
After One Year but not more than Five Years
Commitments [Line Items]
Expenditure commitments relating to services for clinical trial and intellectual property license agreements	$ 2,347,060	293,815	60,000
After more than Five Years
Commitments [Line Items]
Expenditure commitments relating to services for clinical trial and intellectual property license agreements		$ 75,000	$ 90,000

Commitments - Additional Inform

Commitments - Additional Information (Details)	12 Months Ended
	Jun. 30, 2021
Commitments [Abstract]
Termination clause of biggest research contract	60 days
Maximum commitment term	6 months

Contingencies - Additional Info

Contingencies - Additional Information (Details) - USD ($)	Jun. 30, 2021	Jun. 30, 2020
Disclosure Of Contingent Liabilities [Line Items]
Bank guarantee outstanding in respect of rental deposit	$ 43,000	$ 39,391
Within One Year
Disclosure Of Contingent Liabilities [Line Items]
Amount payable		263,241
More Than One Year
Disclosure Of Contingent Liabilities [Line Items]
Amount payable	$ 11,548,205	$ 11,518,745

Cash Flow Statement Reconcili_3

Cash Flow Statement Reconciliation - Summary of Cash Flow Statement Reconciliation (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019	Jul. 01, 2019	Jun. 30, 2018
(a) Reconciliation to cash at the end of the year
Cash at bank and in hand	$ 118,193,177	$ 42,650,858	$ 15,121,820
Cash and cash equivalents	118,193,177	42,650,858	15,121,820	$ 15,121,820	$ 24,080,327
(b) Reconciliation of net loss after tax to net cash flows from operations
Net loss for the year	(45,344,496)	(11,123,199)	(14,951,948)
Adjustments for:
Income tax benefit recognized in profit or loss	(4,938,846)	(5,708,767)	(10,474,432)
Depreciation of non-current assets	15,012	14,926	23,607
Depreciation of right-of-use assets	91,656	81,611	0
Share-based payments	3,897,638	732,688	685,409
Net exchange differences	11,011,961	265,989	(241,814)
Changes in:
Payables	(1,552,443)	(125,492)	(1,209,513)
Receivables	(369,712)	12,127	83,936
Prepayments	(14,231,546)	(30,994)	(81,681)
Provisions	40,510	72,794	26,823
Net cash flows used in operating activities before tax	(51,380,266)	(15,808,317)	(26,139,613)
R&D tax incentive received	5,834,099	10,118,697	9,097,526
Net cash flows used in operating activities	(45,546,167)	(5,689,620)	$ (17,042,087)
(c) Reconciliation of borrowings arising from financing activities
Beginning Balance	167,460
Non-cash addition		251,189
Payment of lease liabilities	(87,373)	(66,781)
Exchange on translation	13,765	(16,948)
Ending Balance	$ 93,852	$ 167,460

Key Management Personnel - Sche

Key Management Personnel - Schedule of Compensation of Key Management Personnel (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Disclosure Of Transactions Between Related Parties [Abstract]
Short-term employee benefits	$ 1,099,081	$ 680,954	$ 715,027
Post-employment benefits	79,550	64,632	67,928
Share-based payments expense	3,897,638	420,751	532,952
Key management personnel compensation	$ 5,076,269	$ 1,166,337	$ 1,315,907

Key Management Personnel - Addi

Key Management Personnel - Additional Information (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Director and Key Management Personnel
Disclosure Of Transactions Between Related Parties [Line Items]
Related party transactions	$ 0	$ 0

Share-Based Payments - Summary

Share-Based Payments - Summary of Recognized Share Based Payment Expenses (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Disclosure Of Detailed Information About Recognized Share Based Payment Expenses [Abstract]
Director and employee services received	$ 3,897,638	$ 732,688	$ 685,409

Share-Based Payments - Addition

Share-Based Payments - Additional Information (Details) - USD ($)	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2015
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Number of employee share converts into ordinary share on exercise				1
Amounts paid or payable by recipient on receipt of option				$ 0
Share options outstanding at end of year weighted average exercise price	$ 0.86	$ 0.50	$ 0.37
Weighted average remaining contractual life	628 days	626 days	716 days
Bottom of Range
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Historical share price volatility period	4 years
Top of Range
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Historical share price volatility period	5 years

Share-Based Payments - Summar_2

Share-Based Payments - Summary of Fair Value of Share Options Granted (Details)	12 Months Ended
	Jun. 30, 2021$ / shares
LTIP - Director FY2016
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Exercise price	$ 0.36
Grant date share price	0.28
Fair value per option US	$ 0.14
Expected volatility	65.00%
Option life	5 years
Dividend yield	0.00%
Risk free interest rate	2.09%
Model used	Binomial
LTIP - Director FY2019
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Exercise price	$ 0.63
Grant date share price	0.42
Fair value per option US	$ 0.15
Expected volatility	58.00%
Option life	4 years
Dividend yield	0.00%
Risk free interest rate	2.04%
Model used	Binomial
LTIP - employees FY2016
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Exercise price	$ 0.37
Grant date share price	0.54
Fair value per option US	$ 0.18
Expected volatility	65.00%
Option life	5 years
Dividend yield	0.00%
Risk free interest rate	2.09%
Model used	Binomial
LTIP - Employees FY2018
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Exercise price	$ 0.92
Grant date share price	0.34
Fair value per option US	$ 0.26
Expected volatility	66.00%
Option life	5 years
Dividend yield	0.00%
Risk free interest rate	2.09%
Model used	Binomial
LTIP - Employees FY2019
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Exercise price	$ 0.61
Grant date share price	0.48
Fair value per option US	$ 0.18
Expected volatility	57.00%
Option life	4 years
Dividend yield	0.00%
Risk free interest rate	2.04%
Model used	Binomial
NED Plan FY2016
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Exercise price	$ 0.36
Grant date share price	0.28
Fair value per option US	$ 0.14
Expected volatility	65.00%
Option life	5 years
Dividend yield	0.00%
Risk free interest rate	2.09%
Model used	Binomial
NED Plan FY2019
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Exercise price	$ 0.63
Grant date share price	0.42
Fair value per option US	$ 0.15
Expected volatility	58.00%
Option life	4 years
Dividend yield	0.00%
Risk free interest rate	2.04%
Model used	Binomial
NED Plan FY2021
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Exercise price	$ 2.16
Grant date share price	2.19
Fair value per option US	$ 1.24
Expected volatility	77.25%
Option life	4 years
Dividend yield	0.00%
Risk free interest rate	0.25%
Model used	Binomial
NED Plan FY2021 Two
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Exercise price	$ 3.24
Grant date share price	2.19
Fair value per option US	$ 1.05
Expected volatility	77.25%
Option life	4 years
Dividend yield	0.00%
Risk free interest rate	0.25%
Model used	Binomial
NED Plan FY2021 Three
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Exercise price	$ 1.56
Grant date share price	1.56
Fair value per option US	$ 0.88
Expected volatility	77.01%
Option life	4 years
Dividend yield	0.00%
Risk free interest rate	0.25%
Model used	Binomial
Non Executive Director and Employee Share Option Plans | LTIP - Director FY2016
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	March 7,2016
Grant date fair value	$ 0.14
Exercise price	$ 0.36
Expiry date	Mar. 7, 2021
Vesting date	Jun. 30, 2016
Non Executive Director and Employee Share Option Plans | LTIP - Director FY2019
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	November 29, 2018
Grant date fair value	$ 0.15
Exercise price	$ 0.625
Expiry date	Nov. 29, 2022
Vesting date	Nov. 29, 2019
Non Executive Director and Employee Share Option Plans | LTIP - employees FY2016
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	March 31, 2016
Grant date fair value	$ 0.18
Exercise price	$ 0.37
Expiry date	Jan. 1, 2022
Vesting date	Jan. 1, 2017
Non Executive Director and Employee Share Option Plans | LTIP - Employees FY2018
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	August 23, 2017
Grant date fair value	$ 0.26
Exercise price	$ 0.92
Expiry date	Jan. 1, 2023
Vesting date	Jun. 30, 2018
Non Executive Director and Employee Share Option Plans | LTIP - Employees FY2019
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	April 3, 2019
Grant date fair value	$ 0.18
Exercise price	$ 0.608
Expiry date	Apr. 3, 2023
Vesting date	Apr. 3, 2021
Non Executive Director and Employee Share Option Plans | NED Plan FY2016
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	March 7,2016
Grant date fair value	$ 0.14
Exercise price	$ 0.36
Expiry date	Mar. 7, 2021
Vesting date	Jun. 30, 2016
Non Executive Director and Employee Share Option Plans | NED Plan FY2019
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	November 29, 2018
Grant date fair value	$ 0.15
Exercise price	$ 0.625
Expiry date	Nov. 29, 2022
Vesting date	Nov. 29, 2019
Non Executive Director and Employee Share Option Plans | NED Plan FY2021
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	October 12, 2020
Grant date fair value	$ 1.05
Exercise price	$ 3.24
Expiry date	Oct. 11, 2024
Vesting date	Oct. 12, 2020
Non Executive Director and Employee Share Option Plans | NED Plan FY2021 Two
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	October 12, 2020
Grant date fair value	$ 1.05
Exercise price	$ 3.24
Expiry date	Oct. 11, 2024
Vesting date	Oct. 12, 2021
Non Executive Director and Employee Share Option Plans | NED Plan FY2021 Three
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	October 12, 2020
Grant date fair value	$ 1.05
Exercise price	$ 3.24
Expiry date	Oct. 11, 2024
Vesting date	Oct. 12, 2022
Non Executive Director and Employee Share Option Plans | NED Plan FY2021 Four
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	October 12, 2020
Grant date fair value	$ 1.05
Exercise price	$ 3.24
Expiry date	Oct. 11, 2024
Vesting date	Oct. 12, 2023
Non Executive Director and Employee Share Option Plans | NED Plan FY2021 Five
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	October 12, 2020
Grant date fair value	$ 1.24
Exercise price	$ 2.16
Expiry date	Oct. 11, 2024
Vesting date	Oct. 12, 2020
Non Executive Director and Employee Share Option Plans | NED Plan FY2021 Six
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	October 12, 2020
Grant date fair value	$ 1.24
Exercise price	$ 2.16
Expiry date	Oct. 11, 2024
Vesting date	Oct. 12, 2021
Non Executive Director and Employee Share Option Plans | NED Plan FY2021 Seven
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	October 12, 2020
Grant date fair value	$ 1.24
Exercise price	$ 2.16
Expiry date	Oct. 11, 2024
Vesting date	Oct. 12, 2022
Non Executive Director and Employee Share Option Plans | NED Plan FY2021 Eight
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	October 12, 2020
Grant date fair value	$ 1.24
Exercise price	$ 2.16
Expiry date	Oct. 11, 2024
Vesting date	Oct. 12, 2023
Non Executive Director and Employee Share Option Plans | NED Plan FY2021 Nine
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	January 19, 2021
Grant date fair value	$ 0.88
Exercise price	$ 1.56
Expiry date	Jan. 18, 2025
Vesting date	Jan. 19, 2021
Non Executive Director and Employee Share Option Plans | NED Plan FY2021 Ten
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	January 19, 2021
Grant date fair value	$ 0.88
Exercise price	$ 1.56
Expiry date	Jan. 18, 2025
Vesting date	Jan. 19, 2022
Non Executive Director and Employee Share Option Plans | NED Plan FY2021 Eleven
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	January 19, 2021
Grant date fair value	$ 0.88
Exercise price	$ 1.56
Expiry date	Jan. 18, 2025
Vesting date	Jan. 19, 2023
Non Executive Director and Employee Share Option Plans | NED Plan FY2021 Twelve
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Line Items]
Grant date	January 19, 2021
Grant date fair value	$ 0.88
Exercise price	$ 1.56
Expiry date	Jan. 18, 2025
Vesting date	Jan. 19, 2024

Share-Based Payments - Summar_3

Share-Based Payments - Summary of Share Options Outstanding (Details)	12 Months Ended
	Jun. 30, 2021shares$ / shares	Jun. 30, 2020shares$ / shares	Jun. 30, 2019shares$ / shares
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Abstract]
Balance, number of options and rights | shares	18,044,000	18,919,000	10,075,000
Number of options granted | shares	7,000,000		8,844,000
Exercised during the year, number of options and rights | shares	(8,400,000)	(875,000)
Balance, number of options and rights | shares	16,644,000	18,044,000	18,919,000
Outstanding options exercisable | shares	11,394,000	18,044,000	9,905,000
Balance, weighted average exercise price | $ / shares	$ 0.50	$ 0.50	$ 0.39
To employees and directors under the LTIP and NED Plan, weighted average exercise price | $ / shares	2.21		0.62
Exercised during the year, weighted average exercise price | $ / shares	0.36	0.37
Balance, weighted average exercise price | $ / shares	1.28	0.50	0.50
Exercisable at end of year, weighted average exercise price | $ / shares	$ 0.86	$ 0.50	$ 0.37