| Significant Accounting Policies (Policies) | 12 Months Ended |
| Mar. 31, 2021 |
| Accounting Policies [Abstract] | |
| Basis of Accounting, Policy [Policy Text Block] | Basis of presentation These consolidated financial statements of Acasti Pharma Inc., which include the accounts of its subsidiary have been prepared in accordance with U.S. GAAP. All intercompany transactions and balances are eliminated on consolidation. The following summarizes the principal conditions or events relevant to the Corporation's going concern assessment, which primarily considers the period of one The Corporation has incurred operating losses and negative cash flows from operations since its inception. In prior years there was substantial doubt regarding the Corporation's ability to realize its assets and discharge its liabilities and commitments in the ordinary course of business. During year ended March 31, 2021, $59.3 March 31, 2021 $60.7 $1.6 March 31, 2021 The Corporation's ability to continue as a going concern is dependent upon its ability to achieve a successful strategic alternative and ultimately generate cashflows to meet its obligations. To date, the Corporation has financed its operations primarily through public offerings of common shares, private placements, and the proceeds from research tax credits, and will require additional financing in the future. Refer to note 21 no not no one |
| Use of Estimates, Policy [Policy Text Block] | Significant accounting policies, estimates and judgments: The preparation of the financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, income, and expenses. Actual results may Estimates are based on management's best knowledge of current events and actions that management may Estimates and assumptions include the measurement of derivative warrant liabilities ( note 10 note 15 6 7 20 |
| Foreign Currency Transactions and Translations Policy [Policy Text Block] | Functional and reporting currency: Effective March 31, 2020, The Corporation's functional currency is the Canadian dollar. The effects of exchange rate fluctuations on translating foreign currency monetary assets and liabilities into Canadian dollars are included in the statement of loss and comprehensive loss as foreign exchange gain/loss. Expense transactions are translated into the U.S. dollar reporting currency at the average exchange rate during the period, and assets and liabilities are translated at end of period exchange rates, except for equity transactions, which are translated at historical exchange rates. |
| Cash and Cash Equivalents, Policy [Policy Text Block] | Cash and Cash Equivalents: Cash and cash equivalents comprise cash balances and highly liquid investments purchased with original maturities of three |
| Marketable Securities, Policy [Policy Text Block] | Investments: The Corporation's investments consist of term deposits and are classified as held-to-maturity securities. These investments are recorded at amortized cost. Investments with original maturities exceeding three one |
| Receivable [Policy Text Block] | Receivables: Receivables are classified at amortized cost and recorded at the outstanding amount net of any provisions for uncollectible amount. |
| Deferred Charges, Policy [Policy Text Block] | Deferred Financing Costs: Deferred financing costs consists of fees charged by underwriters, attorneys, accountants, and other fees directly attributable to future issuances of shares. Provided these costs are determined to be recoverable, these costs are deferred and charged subsequently against the gross proceeds of the related equity transaction when it occurs. If at such time, the Corporation deems that these costs are no |
| Assets Held For Sale Policy [Policy Text Block] | Assets held for sale: Assets that are classified as held for sale are measured at the lower of their carrying amount or fair value less expected selling costs (“estimated selling price”) with a loss recognized to the extent that the carrying amount exceeds the estimated selling price. The classification is applicable at the date upon which the sale of assets is probable, and the assets are available for immediate sale in their present condition. Assets once classified as held for sale, are not |
| Property, Plant and Equipment, Policy [Policy Text Block] | Equipment: (i) Recognition and measurement: Equipment is measured at cost less accumulated depreciation and accumulated impairment losses, if any. Cost includes expenditures that are directly attributable to the acquisition of the asset, including all costs incurred in bringing the asset to its present location and condition. Purchased software that is integral to the functionality of the related equipment is capitalized as part of that equipment. Gains and losses on disposal of equipment are determined by comparing the proceeds from disposal with the carrying amount of equipment and are recognized net within operating expenses in the Consolidated Statement of Loss and Comprehensive Loss. (ii) Subsequent costs: The costs of the day-to-day servicing of equipment are recognized in profit or loss as incurred. (iii) Depreciation: Depreciation is recognized in profit or loss on either a straight-line basis or a declining basis over the estimated useful lives of each part of an item of equipment, since this most closely reflects the expected pattern of consumption of the future economic benefits embodied in the asset. Items of equipment are depreciated from the date that they are available for use or, in respect of assets not The estimated useful lives and rates for the current and comparative periods are as follows: Assets Method Period/Rate Furniture and office equipment Declining balance 20% to 30% Computer equipment Declining balance 30% Laboratory equipment Declining balance 30% Production equipment Declining balance 10% to 30% Depreciation methods, useful lives and residual values are reviewed periodically and adjusted prospectively if appropriate. |
| Goodwill and Intangible Assets, Policy [Policy Text Block] | Intangible assets: Intellectual property and licenses that are acquired by the Corporation from a third Amortization group Amortization is calculated over the cost of the intangible asset less its residual value. Amortization is recognized in profit or loss on a straight-line basis over the estimated useful lives of intangible assets from the date that they are available for use, since this most closely reflects the expected pattern of consumption of the future economic benefits embodied in the asset. The estimated useful lives for the current and comparative periods are as follows: Assets Period (years) Patents 20 License 8 to 14 Subsequent expenditure: Subsequent expenditure is capitalized only when it increases the future economic benefits embodied in the specific asset to which it relates. All other expenditures, including expenditure on internally generated goodwill and brands, are recognized in profit or loss as incurred. |
| Research and Development Expense, Policy [Policy Text Block] | Research and Development Costs Research and developments expenditures are expensed as incurred. These costs primarily consist of employees' salaries and benefits related to research and development activities, contractors and consultants that conduct the Corporation's clinical trials, independent auditors and consultants to perform investigation activities on behalf of the Corporation, laboratory material and small equipment, clinical trial materials, stock-based compensation expense, and other non-clinical costs and regulatory fees. Advance payments for goods and services that will be used in future research and development are recognized in prepaids or other assets and are expensed when the services are performed, or the goods are used. |
| Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] | Impairment of Long-Lived Assets: The Corporation reviews the recoverability of its long-lived assets whenever events or changes in circumstances indicate that it is carrying amount may not first $5,703 March 31, 2021, nil March 31, 2020. |
| Share-based Payment Arrangement [Policy Text Block] | Stock based compensation: The Corporation has in place a stock option plan for directors, officers, employees, and consultants of the Corporation, with grants under the stock option plan approved by the Corporation's Board of Directors. The plan provides for the granting of options to purchase Common Shares and the exercise price of each option equals the closing trading price of Common Shares on the day prior to the grant. The terms and conditions for acquiring and exercising options are set by the Corporation's Board of Directors in accordance with and subject to the terms and conditions of the stock option plan. The Corporation measures the cost of such awards based on the fair value of the award at grant date, net of estimated forfeiture, and recognizes stock-based compensation expense in the Consolidated Statements of Loss and Comprehensive Loss on a graded vesting basis over the requisite service period. The requisite service period equals the vesting periods of the awards. The fair value of options is estimated for each tranche of an award that vests on a graded basis. The fair value of options is estimated using the Black-Scholes option pricing model, which uses various inputs including estimated fair value of the Common Shares at the grant date, expected term, estimated volatility, risk-free interest rate and expected dividend yields of the Common Shares. The Corporation applies an estimated forfeiture rate derived from historical employee termination behaviour. If the actual forfeitures differ from those estimated by management, adjustment to compensation expense may Non-employee stock-based compensation transactions in which the Corporation receives goods or services as consideration for its own equity instruments are accounted for as stock-based compensation transactions. The Corporation establishes the fair value at the grant date for non-employee awards and measures the fair value based on the fair value of equity instruments issued. The fair value of a non-employee award is estimated using the Black-Scholes option pricing model, which uses various inputs including estimated fair value of the Common Shares at the grant date, contractual term, estimated volatility, risk-free interest rate and expected dividend yields of the Common Shares. |
| Government Grants [Policy Text Block] | Government grants: Government grants are recorded as a reduction of the related expense or cost of the asset acquired. Government grants are recognized when there is reasonable assurance that the Corporation has met the requirements of the approved grant program and there is reasonable assurance that the grant will be received. Grants that compensate the Corporation for expenses incurred are recognized in profit or loss in reduction thereof on a systematic basis in the same years in which the expenses are recognized. Grants that compensate the Corporation for the cost of an asset are recognized in profit or loss on a systematic basis over the useful life of the asset. |
| Lessee, Leases [Policy Text Block] | Leases: Adoption of Topic 842 On April 1, 2019, 842. no April 1, 2019, 842 Operating lease liabilities and their corresponding right-of-use assets are initially recorded based on the present value of lease payments over the expected remaining lease term. Certain adjustments to the right-of-use asset may not not The Corporation has elected not one not March 31, 2020, $147. two 8%. $80 |
| Income Tax, Policy [Policy Text Block] | Income tax: Income tax expense comprises current and deferred taxes. Current and deferred taxes are recognized in profit or loss except to the extent that they relate to items recognized directly in equity or in other comprehensive income. Current tax is the expected tax payable or receivable on the taxable income or loss for the year, using tax rates enacted at the reporting date, and any adjustment to tax payable in respect of previous years. Deferred tax is recognized in respect of temporary differences between the carrying amounts (tax base) of assets and liabilities for financial reporting purposes and the amounts used for taxation purposes. Deferred tax assets and liabilities are measured at the tax rate expected to apply when the underlying asset or liability is realised (settled) based on the rates that are enacted at the reporting date. Deferred tax assets and liabilities are offset if the Corporation has the right to set off the amount owed by with the amount owed by the other party, the Corporation intends to set off and the offset right is enforceable at law. A deferred tax asset is recognized for unused tax losses and tax credits, reduced by a valuation allowance to the extent that it is more likely than not not |
| Earnings Per Share, Policy [Policy Text Block] | Earnings per share: The Corporation presents basic and diluted earnings per share ( EPS |
| Segment Reporting, Policy [Policy Text Block] | Segment reporting: An operating segment is a component of the Corporation that engages in business activities from which it may one one $156 March 31, 2020 - $1,510 third |
| Debt, Policy [Policy Text Block] | Convertible Debentures: The unsecured convertible debentures that existed in the financial statements for the year ended March 31, 2020, February 2020. not not not |
| Derivatives, Policy [Policy Text Block] | Derivative financial instruments: The Corporation has issued warrants of which some are accounted for as liability-classified derivatives over its own equity. Derivatives are recognized initially at fair value; attributable transaction costs are recognized in profit and loss as incurred. Subsequent to initial recognition, derivatives are measured at fair value, and all changes in their fair value are recognized immediately in profit or loss as a component of financial expenses. |
| Stockholders' Equity, Policy [Policy Text Block] | Other equity instruments Warrants that do not |
| Fair Value Measurement, Policy [Policy Text Block] | Fair Value Measurements Certain of the Corporation's accounting policies and disclosures require the determination of fair value, for both financial assets and liabilities. Fair values have been determined for measurement and/or disclosure purposes based on the following methods. |
| Fair Value of Financial Instruments, Policy [Policy Text Block] | Financial assets and liabilities: In establishing fair value, the Corporation uses a fair value hierarchy based on levels as defined below: · Level 1: · Level 2: · Level 3: no The Corporation has determined that the carrying values of its short-term financial assets and liabilities (cash and cash equivalents, short-term investments and trade and other payables) approximate their fair value given the short-term nature of these instruments. The Corporation measured its derivative warrant liabilities at fair value on a recurring basis using level 3 . |
