Significant accounting policies	6 Months Ended
Significant accounting policies	Jun. 30, 2023
Accounting Policies [Abstract]
Significant accounting policies	Significant accounting policies Basis of presentation and principles of consolidation These unaudited condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles for interim financial statements and accordingly, do not include all disclosures required for annual financial statements. These statements should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto for the year ended December 31, 2022 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022. These unaudited condensed consolidated financial statements include the accounts of Arbutus Biopharma Corporation and its one wholly-owned subsidiary, Arbutus Biopharma, Inc., and reflect, in the opinion of management, all adjustments and reclassifications necessary to fairly present the Company’s financial position as of June 30, 2023 and December 31, 2022, the Company’s results of operations for the three and six months ended June 30, 2023 and 2022, and the Company’s cash flows for the six months ended June 30, 2023 and 2022. Such adjustments are of a normal recurring nature. The results of operations for the three and six months ended June 30, 2023 are not necessarily indicative of the results for the full year. These unaudited condensed consolidated financial statements follow the same significant accounting policies as those described in the notes to the audited consolidated financial statements of the Company for the year ended December 31, 2022, except as described below under Recent Accounting Pronouncements. All intercompany balances and transactions have been eliminated. Certain prior year amounts have been reclassified to conform to the current year presentation. Net loss per share Net loss per share is calculated based on the weighted average number of common shares outstanding. Diluted net loss per share does not differ from basic net loss per share for the three and six months ended June 30, 2023 and 2022, since the effect of including potential common shares would be anti-dilutive. For the six months ended June 30, 2023, potential common shares of 20.2 million pertaining to outstanding stock options and unvested restricted stock units were excluded from the calculation of net loss per share. A total of approximately 15.9 million outstanding stock options were excluded from the calculation for the six months ended June 30, 2022. Revenue from collaborations and licenses The Company generates revenue through certain collaboration agreements and license agreements. Such agreements may require the Company to deliver various rights and/or services, including intellectual property rights or licenses and research and development services. Under such agreements, the Company is generally eligible to receive non-refundable upfront payments, funding for research and development services, milestone payments and royalties. The Company’s collaboration agreements fall under the scope of Accounting Standards Codification (“ASC”) Topic 808, Collaborative Arrangements (“ASC 808”), when both parties are active participants in the arrangement and are exposed to significant risks and rewards. For certain arrangements under the scope of ASC 808, the Company analogizes to ASC Topic 606, Revenue from Contracts with Customers (“ASC 606”), for some aspects, including for the delivery of a good or service (i.e., a unit of account). ASC 606 requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers under a five-step model: (i) identify contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when or as a performance obligation is satisfied. In contracts where the Company has more than one performance obligation to provide its customer with goods or services, each performance obligation is evaluated to determine whether it is distinct based on whether (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available and (ii) the good or service is separately identifiable from other promises in the contract. The consideration under the contract is then allocated between the distinct performance obligations based on their respective relative stand-alone selling prices. The estimated stand-alone selling price of each deliverable reflects the Company’s best estimate of what the selling price would be if the deliverable was regularly sold on a stand-alone basis and is determined by reference to market rates for the good or service when sold to others or by using an adjusted market assessment approach if the selling price on a stand-alone basis is not available. The consideration allocated to each distinct performance obligation is recognized as revenue when control is transferred to the customer for the related goods or services. Consideration associated with at-risk substantive performance milestones, including sales-based milestones, is recognized as revenue when it is probable that a significant reversal of the cumulative revenue recognized will not occur. Sales-based royalties received in connection with licenses of intellectual property are subject to a specific exception in the revenue standards, whereby the consideration is not included in the transaction price and recognized in revenue until the customer’s subsequent sales or usages occur. Deferred Revenue When consideration is received or is unconditionally due from a customer, collaborator or licensee prior to the Company completing its performance obligation to the customer, collaborator or licensee under the terms of a contract, deferred revenue is recorded. Deferred revenue expected to be recognized as revenue within the 12 months following the balance sheet date is classified as a current liability. Deferred revenue not expected to be recognized as revenue within the 12 months following the balance sheet date is classified as a long-term liability. In accordance with ASC Topic 210-20, Balance Sheet - Offsetting (“ASC 210-20”) the Company’s deferred revenue is offset by a contract asset as further discussed in Note 9. Segment information The Company operates as a single segment. Recent accounting pronouncements In June 2016, the Financial Accounting Standards Board issued Accounting Standards Update 2016-13, Financial Instruments - Credit Losses: Measurement of Credit Losses in Financial Instruments (“ASC 326”). The guidance is effective for the Company beginning January 1, 2023 and it changes how entities account for credit losses on the financial assets and other instruments that are not measured at fair value through net income, including available-for-sale debt securities. The adoption of ASC 326 did not have a material impact on the consolidated financial statements. The Company has reviewed all other recently issued standards and has determined that such standards will not have a material impact on the Company’s financial statements or do not otherwise apply to the Company’s operations.