Arbutus Biopharma (ABUS) 10-K 2 Mar 23 2022 FY Annual report Financial data

Cover

Cover - USD ($)	12 Months Ended
	Dec. 31, 2022	Feb. 28, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2022
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-34949
Entity Registrant Name	Arbutus Biopharma Corp
Entity Incorporation, State or Country Code	A1
Entity Tax Identification Number	98-0597776
Entity Address, Address Line One	701 Veterans Circle
Entity Address, City or Town	Warminster
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	18974
City Area Code	267
Local Phone Number	469-0914
Title of 12(b) Security	Common shares, without par value
Trading Symbol	ABUS
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 290,424,678
Entity Common Stock, Shares Outstanding		162,570,989
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s definitive proxy statement for its 2023 Annual Meeting of Shareholders, which the registrant intends to file pursuant to Regulation 14A with the Securities and Exchange Commission no later than 120 days after the registrant’s fiscal year ended December 31, 2022, are incorporated by reference into Part III of this Form 10-K.
Amendment Flag	false
Entity Central Index Key	0001447028
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2022
Audit Information [Abstract]
Auditor Name	Ernst & Young LLP
Auditor Location	Philadelphia, Pennsylvania
Auditor Firm ID	42

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 30,776	$ 109,282
Investments in marketable securities, current	116,137	46,035
Accounts receivable	1,352	899
Prepaid expenses and other current assets	2,874	4,445
Total current assets	151,139	160,661
Property and equipment, net of accumulated depreciation	5,070	5,983
Investments in marketable securities, non-current	37,363	35,688
Right of use asset	1,744	2,092
Other non-current assets	103	61
Total assets	195,419	204,485
Current liabilities:
Accounts payable and accrued liabilities	16,029	10,838
Deferred Revenue, Current	16,456	0
Lease liability, current	372	383
Total current liabilities	32,857	11,221
Liability related to sale of future royalties	10,365	16,296
Deferred Revenue, Noncurrent	5,999	0
Contingent consideration	7,531	5,298
Lease liability, non-current	1,815	2,231
Total liabilities	58,567	35,046
Stockholders’ equity
Common shares, Authorized: unlimited number without par value, Issued and outstanding: 144,987,736 (December 31, 2020: 89,678,722)	1,318,737	1,286,636
Additional paid-in capital	72,406	65,485
Deficit	(1,203,803)	(1,134,347)
Accumulated other comprehensive loss	(50,488)	(48,335)
Total stockholders' equity	136,852	169,439
Total liabilities and stockholders' equity	$ 195,419	$ 204,485

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - shares	Dec. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Common shares, shares issued (in shares)	157,455,363	144,987,736
Common shares, shares outstanding (in shares)	157,455,363	144,987,736

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Revenue
Revenues	$ 39,019	$ 10,988
Operating expenses
Research and development	84,408	65,502
General and administrative	17,834	17,136
Change in fair value of contingent consideration	2,233	1,872
Total operating expenses	104,475	84,510
Loss from operations	(65,456)	(73,522)
Other income (loss)
Interest income	2,192	127
Interest expense	(1,726)	(2,857)
Foreign exchange (loss) gain	(22)	5
Total other income (loss)	444	(2,725)
Loss before income taxes	(65,012)	(76,247)
Income tax expense	4,444	0
Net loss	(69,456)	(76,247)
Items applicable to preferred shares
Dividend accretion of convertible preferred shares	0	(12,139)
Net loss attributable to common shares	$ (69,456)	$ (88,386)
Loss per share
Basic (in USD per share)	$ (0.46)	$ (0.83)
Diluted (in USD per share)	$ (0.46)	$ (0.83)
Weighted average number of common shares
Basic (in shares)	150,939,337	106,242,452
Diluted (in shares)	150,939,337	106,242,452
Comprehensive loss
Unrealized loss on available-for-sale securities	$ (2,153)	$ (164)
Comprehensive loss	(71,609)	(76,411)
Collaborations and licenses
Revenue
Revenues	31,366	4,880
Non-cash royalty revenue
Revenue
Revenues	$ 7,653	$ 6,108

Consolidated Statement of Stock

Consolidated Statement of Stockholders’ Equity - USD ($) $ in Thousands	Total	Convertible Preferred Shares	Common Shares	Additional paid-in capital	Deficit	Accumulated other comprehensive loss
Shares, Issued, Beginning Balance at Dec. 31, 2020		1,164,000	89,678,722
Beginning balance at Dec. 31, 2020	$ 101,966	$ 149,408	$ 985,939	$ 60,751	$ (1,045,961)	$ (48,171)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accretion of accumulated dividends on Preferred Shares	0	$ 12,139			(12,139)
Preferred stock, shares issued (in shares)		(1,164,000)
Common shares, shares issued (in shares)			22,833,922
Conversion of Preferred Shares into Common Shares	0	$ (161,547)	$ 161,547
Stock-based compensation	6,385			6,385
Certain fair value adjustments to liability stock option awards	263			263
Issuance of common shares pursuant to the Open Market Sales Agreement (in shares)			31,571,036
Issuance of common shares pursuant to the Open Market Sales Agreement	$ 134,665		$ 134,665
Issuance of common shares pursuant to exercise of ESPP options (in shares)	196,335		196,335
Issuance of common shares pursuant to exercise of ESPP	$ 461		$ 817	(356)
Issuance of common shares pursuant to exercise of options (in shares)			707,721
Issuance of common shares pursuant to exercise of stock options	2,110		$ 3,668	(1,558)
Unrealized loss on available-for-sale securities	(164)					(164)
Net loss	(76,247)				(76,247)
Ending balance (in shares) at Dec. 31, 2021		0	144,987,736
Ending balance at Dec. 31, 2021	169,439	$ 0	$ 1,286,636	65,485	(1,134,347)	(48,335)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	7,182			7,182
Certain fair value adjustments to liability stock option awards	26			26
Issuance of common shares pursuant to the Open Market Sales Agreement (in shares)			8,645,426
Issuance of common shares pursuant to the Open Market Sales Agreement	$ 20,324		$ 20,324
Issuance of common shares pursuant to exercise of ESPP options (in shares)	171,224		171,224
Issuance of common shares pursuant to exercise of ESPP	$ 395		$ 588	(193)
Issuance of common shares pursuant to Share Purchase Agreement (in shares)			3,579,952
Issuance of common shares pursuant to Share Purchase Agreement	10,973		$ 10,973
Issuance of common shares pursuant to exercise of options (in shares)			71,025
Issuance of common shares pursuant to exercise of stock options	122		$ 216	(94)
Unrealized loss on available-for-sale securities	(2,153)					(2,153)
Net loss	(69,456)				(69,456)
Ending balance (in shares) at Dec. 31, 2022		0	157,455,363
Ending balance at Dec. 31, 2022	$ 136,852	$ 0	$ 1,318,737	$ 72,406	$ (1,203,803)	$ (50,488)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
OPERATING ACTIVITIES
Net loss	$ (69,456)	$ (76,247)
Non-cash items:
Depreciation	1,427	1,753
Stock-based compensation expense	7,182	6,424
Change in fair value of contingent consideration	2,233	1,872
Non-cash royalty revenue	(7,653)	(6,108)
Non-cash interest expense	1,722	2,850
Net accretion and amortization of investments in marketable securities	(54)	999
Net change in operating items:
Accounts receivable	(453)	413
Prepaid expenses and other assets	2,430	(1,025)
Accounts payable and accrued liabilities	5,216	1,911
Deferred license revenue	22,455	0
Other liabilities	(405)	(374)
Net cash used in operating activities	(35,356)	(67,532)
INVESTING ACTIVITIES
Purchase of investments in marketable securities	(130,430)	(82,219)
Disposition of investments in marketable securities	56,000	70,350
Acquisition of property and equipment	(512)	(809)
Net cash used in investing activities	(74,942)	(12,678)
FINANCING ACTIVITIES
Issuance of common shares pursuant to Share Purchase Agreement	10,973	0
Issuance of common shares pursuant to the ATM	20,324	134,665
Issuance of common shares pursuant to exercise of stock options	122	2,110
Issuance of common shares pursuant to exercise of ESPP	395	461
Net cash provided by financing activities	31,814	137,236
Effect of foreign exchange rate changes on cash and cash equivalents	(22)	5
(Decrease) increase in cash and cash equivalents	(78,506)	57,031
Cash and cash equivalents, beginning of period	109,282	52,251
Cash and cash equivalents, end of period	30,776	109,282
Supplemental cash flow information
Preferred shares dividends accrued	$ 0	$ (12,139)

Organization

Organization	12 Months Ended
	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Description of the Business Arbutus Biopharma Corporation (“Arbutus” or the “Company”) is a clinical-stage biopharmaceutical company leveraging its extensive virology expertise to develop novel therapeutics that target specific viral diseases. The Company’s current focus areas include Hepatitis B virus (“HBV”), SARS-CoV-2 and other coronaviruses. To address HBV, the Company is developing an RNA interference (“RNAi”) therapeutic, an oral PD-L1 inhibitor, and an oral RNA destabilizer to potentially identify a combination regimen with the aim of providing a functional cure for patients with chronic HBV infection (“cHBV”) by suppressing viral replication, reducing surface antigen and reawakening the immune system. The Company believes its lead compound, AB-729, is the only RNAi therapeutic with evidence of immune re-awakening. AB-729 is currently being evaluated in multiple phase 2 clinical trials. The Company also has an ongoing drug discovery and development program directed to identifying novel, orally active agents for treating coronaviruses, including SARS-CoV-2, where the Company has nominated a compound and has begun IND-enabling pre-clinical studies. In addition, the Company is also exploring oncology applications for its internal PD-L1 portfolio. Liquidity At December 31, 2022, the Company had an aggregate of $184.3 million in cash, cash equivalents and investments in marketable securities. The Company had no outstanding debt as of December 31, 2022. The Company believes it has sufficient cash resources to fund its operations for at least the next 12 months. The success of the Company is dependent on obtaining the necessary regulatory approvals to bring its products to market and achieve profitable operations. The Company’s research and development activities and the commercialization of its products are dependent on its ability to successfully complete these activities and to obtain adequate financing through a combination of financing activities and operations. It is not possible to predict either the outcome of the Company’s existing or future research and development programs or the Company’s ability to continue to fund these programs in the future. COVID-19 Impact The Company continues to monitor the effects of COVID-19, which has caused significant disruptions around the world. Measures implemented around the world in attempts to slow the spread of COVID-19 have had, and will likely continue to have, a major impact on clinical development, at least in the near-term, including shortages and delays in the supply chain, and prohibitions in certain countries on enrolling patients in new clinical trials.

Significant accounting policies

Significant accounting policies	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Significant accounting policies	Significant accounting policies Basis of presentation and principles of consolidation These consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and include the accounts of Arbutus Biopharma Corporation and its one wholly-owned subsidiary, Arbutus Biopharma, Inc. All intercompany balances and transactions have been eliminated. Certain prior year amounts have been reclassified to conform to the current year presentation. In February 2021, Arbutus Biopharma US Holdings, Inc., which was another wholly-owned subsidiary, merged into Arbutus Biopharma, Inc. with Arbutus Biopharma, Inc. continuing its legal existence and Arbutus Biopharma US Holdings, Inc. ceasing to exist. Use of estimates The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions about future events that affect the reported amounts of assets, liabilities, revenue, expenses and contingent liabilities as of the end or during the reporting period. Actual results could significantly differ from those estimates. Significant estimates in the accompanying consolidated financial statements impact contingent consideration, income tax recoveries, stock-based compensation, clinical trial accruals and the sale of future royalties liability. Cash and cash equivalents Cash and cash equivalents are all highly liquid instruments with an original maturity of three months or less when purchased. Cash equivalents are recorded at cost plus accrued interest. The carrying value of these cash equivalents approximates their fair value. Investments in marketable securities The Company’s short-term investments consist of marketable securities that have original maturities exceeding three months and remaining maturities of less than one year. The Company classifies investments with remaining maturities of one year or longer as non-current. These investments are accounted for as available-for-sale securities and are reported at fair value, with unrealized gains and losses reported in other comprehensive loss until their disposition. Realized gains and losses from the sale of marketable securities, if any, are calculated using the specific-identification method, and are recorded as a component of other income or loss. The Company reviews its available-for-sale securities at each period end to determine if they remain available-for-sale based on the Company’s current intent and ability to sell the security if it is required to do so. Declines in value judged to be other-than-temporary are included in interest expense in the Company’s statements of operations and comprehensive loss. As of December 31, 2022, the recorded value of the Company’s investments in marketable securities was deemed to be recoverable in all respects. All investments are governed by the Company’s Investment Policy approved by the Company’s board of directors. Foreign currency translation and functional currency conversion The Company’s functional currency is the United States dollar. M onetary assets and liabilities denominated in foreign currencies are translated into United States dollars using exchange rates in effect at the balance sheet date. Opening balances related to non-monetary assets and liabilities are based on prior period translated amounts, and non-monetary assets and non-monetary liabilities are translated at the approximate exchange rate prevailing at the date of the transaction. Revenue and expense transactions are translated at the approximate exchange rate in effect at the time of the transaction. Foreign exchange gains and losses are included in the statement of operations and comprehensive loss as foreign exchange gains or losses. Investment in Genevant Arbutus accounts for its interest in Genevant as equity securities without readily determinable fair values. Accordingly, an estimate of the fair value of the securities is based on the original cost less previously recognized equity method losses, less impairments, plus or minus changes resulting from observable price changes in orderly transactions for identical or similar Genevant securities. As of December 31, 2022, Arbutus owned approximately 16% of the common equity of Genevant and the carrying value of Arbutus’ investment in Genevant was zero. See note 5 for more information. Property and equipment Property and equipment is recorded at cost less impairment losses and accumulated depreciation. The Company records depreciation using the straight-line method over the estimated useful lives of the capital assets as follows: Useful Life (Years) Laboratory equipment 5 Computer and office equipment 2 to 5 Furniture and fixtures 5 Leasehold improvements are depreciated over their estimated useful lives but in no case longer than the lease term, except where lease renewal is reasonably assured. Property and equipment is reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. If such a review should indicate that the carrying amount of long-lived assets is not recoverable, then such assets are written down to their fair values. Revenue from collaborations and licenses The Company generates revenue primarily through 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, development and manufacturing services. Under such agreements, the Company is generally eligible to receive non-refundable upfront payments, funding for research, development and manufacturing services, milestone payments, and royalties. The Company’s collaboration agreements fall under the scope of 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 606 for some aspects, including for the delivery of a good or service (i.e., a unit of account). ASC 606, Revenue From Contracts with Customers (“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. Leases The Company accounts for its lease under ASC 842, Leases , which generally requires the recognition of operating and financing lease liabilities with corresponding right-of-use assets on the balance sheet. See note 6 for more information. Research and development costs Research and development costs include compensation and benefits for research and development employees, an allocation of overhead expenses and costs associated with materials and supplies used in clinical trials and research and development, outside contracted services including clinical and pre-clinical study costs, legal, regulatory compliance and fees paid to consultants or outside parties for research and development activities performed on the Company’s behalf. Such costs are charged to expense in the period in which they are incurred. Research and development costs that are paid in advance of performance or receipt are recorded as prepaid expense and are amortized over the period that the services are performed. Net loss attributable to common shareholders per share Net loss attributable to common shareholders per share is calculated based on the weighted average number of common shares outstanding. Diluted net loss attributable to common shareholders per share does not differ from basic net loss attributable to common shareholders per share for the years ended December 31, 2022 and 2021, since the effect of including potential common shares would be anti-dilutive. For the year ended December 31, 2022, potential common shares of 15.5 million pertaining to outstanding stock options were excluded from the calculation of net loss attributable to common shareholders per share. A total of approximately 11.4 million outstanding stock options were excluded from the calculation for the year ended December 31, 2021. On October 18, 2021, the Company’s outstanding Series A participating convertible preferred shares (“ Preferred Shares”) were converted into 22,833,922 common shares. Prior to that date, the Company followed the two-class method when computing net loss attributable to common shareholders per share as the Preferred Shares, as further described in note 12, met the definition of participating securities. The Company’s Preferred Shares entitled the holders to participate in dividends but did not require the holders to participate in losses of the Company. Accordingly, net losses attributable to holders of the Company’s common shares were not allocated to holders of the Preferred Shares. See note 12 and note 13 for more information about the Company’s common shares. Deferred income taxes Income taxes are accounted for using the asset and liability method of accounting. Deferred income taxes are recognized for the future income tax consequences attributable to differences between the carrying values of assets and liabilities and their respective income tax bases and for loss carry-forwards. Deferred income tax assets and liabilities are measured using enacted income tax rates expected to apply to taxable income in the periods in which temporary differences are expected to be recovered or settled. The effect on deferred income tax assets and liabilities of a change in tax laws or rates is included in earnings in the period that includes the enactment date. When realization of deferred income tax assets does not meet the more-likely-than-not criterion for recognition, a valuation allowance is provided. Stock-based compensation The Company measures and recognizes compensation expense for all share-based compensation arrangements based on estimated fair values. The Company uses the Black-Scholes option valuation model to estimate the fair value of stock options at the date of grant. The Black-Scholes option valuation model requires the input of subjective assumptions to calculate the value of stock options. For those assumptions, the Company uses historical data and other information to estimate the expected price volatility and risk free interest rate for all awards. The expected life of stock options granted are estimated to be five years for employees and six years for directors and executives, based on the Company’s historical experience. Assumptions on the dividend yield are based on the fact that the Company has never paid cash dividends and has no present intention to pay cash dividends. Expense is recognized over the vesting period for all awards and commences at the grant date for time-based awards and upon the Company’s determination that the achievement of such performance conditions is probable for performance-based awards. Forfeitures are recognized as they occur. For the Company’s Employee Stock Purchase Plan, the fair value of the right to acquire stock at a discounted price under the plan is calculated using the Black-Scholes valuation model. Expense is recognized over the period the employee contributes to the plan through payroll deductions. The Company accounts for liability-classified stock option awards (“liability options”) under ASC 718 - Compensation - Stock Compensation (“ASC 718”), under which awards of options that provide for an exercise price that is not denominated in: (a) the currency of a market in which a substantial portion of the Company’s equity securities trades, (b) the currency in which the employee’s pay is denominated, or (c) the Company’s functional currency, are required to be classified as liabilities. As of January 1, 2016, the Company changed its functional currency to US dollars, which resulted in certain stock option awards with exercise prices denominated in Canadian dollars having an exercise price that is not denominated in the Company’s functional currency. As such, the historic equity classification of these stock option awards changed to liability classification effective January 1, 2016. The change in classification resulted in reclassification of these awards from additional paid-in capital to a liability. Liability options are re-measured to their fair values at each reporting date with changes in the fair value recognized in share-based compensation expense or additional paid-in capital until settlement or cancellation. Under ASC 718, when an award is reclassified from equity to liability, if at the reclassification date the original vesting conditions are expected to be satisfied, then the minimum amount of compensation cost to be recognized is based on the grant date fair value of the original award. Fair value changes below this minimum amount are recorded in additional paid-in capital. Preferred Shares The Company accounted for its Preferred Shares under ASC 480 – Distinguishing Liabilities from Equity (“ASC 480”), which provides guidance for equity instruments with conversion features. The Company classified the Preferred Shares in its consolidated balance sheet wholly as equity, with no bifurcation of conversion feature from the host contract, given that the Preferred Shares could not be cash-settled and the redemption features, which included a fixed conversion ratio with predetermined timing and proceeds, were within the Company’s control. The Company accrued for the 8.75% per annum compounding accrual at each reporting period-end date as an increase to share capital, and an increase to deficit. The Company’s Preferred Shares were converted into 22,833,922 common shares on October 18, 2021. Segment information As of December 31, 2022, the Company viewed its operations and managed its business as one operating segment consistent with how its chief operating decision-maker, the Chief Executive Officer, makes decisions regarding resource allocation and assessing performance. Substantially all of the Company’s premises, property and equipment are located in the United States. Comprehensive loss Comprehensive loss is comprised of net loss and adjustments for the change in unrealized gains and losses on investments in available-for-sale marketable securities. The Company includes comprehensive loss and its components in the consolidated statements of operations and comprehensive loss, net of tax effects if any. Concentrations of Credit Risk Financial instruments which potentially subject the Company to credit risk consist primarily of cash, cash equivalents and marketable securities. The Company holds these investments in highly rated financial institutions, and, by policy, limits the amounts of credit exposure to any one financial institution. These amounts at times may exceed federally insured limits. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to any significant credit risk on these funds. The Company has no off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts or other hedging arrangements. Recent accounting pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13, Financial Instruments - Credit Losses: Measurement of Credit Losses on 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 financial assets and other instruments that are not measured at fair value through net income, including available-for-sale debt securities. The Company does not anticipate that the new guidance will have a material impact on its results of operations or financial position.

Fair value measurements

Fair value measurements	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair value measurements	Fair value measurements The Company measures certain financial instruments and other items at fair value. To determine the fair value, the Company uses the fair value hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. Observable inputs are inputs market participants would use to value an asset or liability and are developed based on market data obtained from independent sources. Unobservable inputs are inputs based on assumptions about the factors market participants would use to value an asset or liability. The three levels of inputs that may be used to measure fair value are as follows: • Level 1 inputs are quoted market prices for identical instruments available in active markets. The Company’s cash and cash equivalents are measured using Level 1 inputs. • Level 2 inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability either directly or indirectly. If the asset or liability has a contractual term, the input must be observable for substantially the full term. An example includes quoted market prices for similar assets or liabilities in active markets. The Company’s investments in marketable securities are measured using Level 2 inputs. • Level 3 inputs are unobservable inputs for the asset or liability and will reflect management’s assumptions about market assumptions that would be used to price the asset or liability. The Company’s liability-classified options and contingent consideration are measured using Level 3 inputs. Assets and liabilities are classified based on the lowest level of input that is significant to the fair value measurements. Changes in the observability of valuation inputs may result in a reclassification of levels for certain securities within the fair value hierarchy. The carrying values of cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate their fair values due to the immediate or short-term maturity of these financial instruments. To determine the fair value of the contingent consideration (note 10), the Company uses a probability weighted assessment of the likelihood the milestones would be met and the estimated timing of such payments, and then the potential contingent payments were discounted to their present value using a probability adjusted discount rate that reflects the early stage nature of the development program, time to complete the program development, and overall biotech indices. The Company determined that the fair value of the contingent consideration was $7.5 million as of December 31, 2022 and the increase of $2.2 million has been recorded within operating expenses in the statement of operations and comprehensive loss for the year ended December 31, 2022. The assumptions used in the discounted cash flow model are level 3 inputs as defined above. The Company assessed the sensitivity of the fair value measurement to changes in these unobservable inputs, and determined that changes within a reasonable range would not result in a materially different assessment of fair value. The following tables present information about the Company’s assets and liabilities that are measured at fair value on a recurring basis, and indicates the fair value hierarchy of the valuation techniques used to determine such fair value: Level 1 Level 2 Level 3 Total As of December 31, 2022 (in thousands) Assets Cash and cash equivalents $ 30,776 $ — $ — $ 30,776 Investments in marketable securities, current — 116,137 — 116,137 Investments in marketable securities, non-current — 37,363 — 37,363 Total $ 30,776 $ 153,500 $ — $ 184,276 Liabilities Liability-classified options $ — $ — $ 1 $ 1 Contingent consideration — — 7,531 7,531 Total $ — $ — $ 7,532 $ 7,532 Level 1 Level 2 Level 3 Total As of December 31, 2021 (in thousands) Assets Cash and cash equivalents $ 109,282 $ — $ — $ 109,282 Investments in marketable securities, current — 46,035 — 46,035 Investments in marketable securities, non-current — 35,688 — 35,688 Total $ 109,282 $ 81,723 $ — $ 191,005 Liabilities Liability-classified options $ — $ — $ 26 $ 26 Contingent consideration — — 5,298 5,298 Total $ — $ — $ 5,324 $ 5,324 The following table presents the changes in fair value of the Company’s liability-classified stock option awards: Liability at beginning of the period Fair value of liability-classified options exercised in the period Decrease in fair value of liability Liability at end of the period (in thousands) Year ended December 31, 2022 $ 26 $ — $ (25) $ 1 Year ended December 31, 2021 $ 250 $ (96) $ (128) $ 26 The following table presents the changes in fair value of the Company’s contingent consideration: Liability at beginning of the period Increase in fair value of liability Liability at end of the period (in thousands) Year ended December 31, 2022 $ 5,298 $ 2,233 $ 7,531 Year ended December 31, 2021 $ 3,426 $ 1,872 $ 5,298

Investments in marketable secur

Investments in marketable securities	12 Months Ended
	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Investments in marketable securities	Investments in marketable securities Investments in marketable securities and cash equivalents consisted of the following: Amortized Cost Gross Unrealized Gain (1) Gross Unrealized Loss (1) Fair Value As of December 31, 2022 (in thousands) Cash equivalents Money market fund $ 23,218 $ — $ — $ 23,218 Total $ 23,218 $ — $ — $ 23,218 Investments in marketable short-term securities US government agency bonds $ 26,686 $ — $ (424) $ 26,262 US corporate bonds 27,144 — (303) 26,841 US treasury bills 8,483 — (16) 8,467 US government bonds 55,361 — (794) 54,567 Total $ 117,674 $ — $ (1,537) $ 116,137 Investments in marketable long-term securities US government agency bonds $ 3,724 $ — $ (130) $ 3,594 US corporate bonds 25,433 — (336) 25,097 US government bonds 8,972 — (300) 8,672 Total $ 38,129 $ — $ (766) $ 37,363 (1) Gross unrealized gain (loss) is pre-tax and is reported in accumulated other comprehensive loss. Amortized Cost Gross Unrealized Gain (1) Gross Unrealized Loss (1) Fair Value As of December 31, 2021 (in thousands) Cash equivalents Money market fund $ 93,211 $ — $ — $ 93,211 Total $ 93,211 $ — $ — $ 93,211 Investments in marketable short-term securities US government agency bonds $ 8,131 $ — $ (11) $ 8,120 US government bonds 37,968 — (53) 37,915 Total $ 46,099 $ — $ (64) $ 46,035 Investments in marketable long-term securities US government agency bonds $ 13,068 $ — $ (29) $ 13,039 US treasury bills 22,707 — (58) 22,649 Total $ 35,775 $ — $ (87) $ 35,688 (1) Gross unrealized gain (loss) is pre-tax and is reported in accumulated other comprehensive loss. The contractual maturity of the $116.1 million of short-term marketable securities held by the Company as of December 31, 2022 is less than one year. As of December 31, 2022, the Company held $37.4 million of long-term marketable securities with contractual maturities of more than one year, but less than five years. As of December 31, 2021, the Company’s $46.0 million of short-term marketable securities had contractual maturities of less than one year, while the Company’s $35.7 million of long-term marketable securities had maturities of more than one year, but less than five years.

Investment in Genevant

Investment in Genevant	12 Months Ended
	Dec. 31, 2022
Equity Method Investments and Joint Ventures [Abstract]
Investment in Genevant	Investment in Genevant In April 2018, the Company entered into an agreement with Roivant Sciences Ltd. (“Roivant”), its largest shareholder, to launch Genevant Sciences Ltd. (“Genevant”), a company focused on a broad range of RNA-based therapeutics enabled by the Company’s LNP and ligand conjugate delivery technologies. The Company licensed rights to its LNP and ligand conjugate delivery platforms to Genevant for RNA-based applications outside of HBV, except to the extent certain rights had already been licensed to other third parties (the “Genevant License”). The Company retained all rights to its LNP and conjugate delivery platforms for HBV. Under the Genevant License, as amended, if a third party sublicensee of intellectual property licensed by Genevant from the Company commercializes a sublicensed product, the Company becomes entitled to receive a specified percentage of certain revenue that may be received by Genevant for such sublicense, including royalties, commercial milestones and other sales-related revenue, or, if less, tiered low single-digit royalties on net sales of the sublicensed product. The specified percentage is 20% in the case of a mere sublicense (i.e., naked sublicense) by Genevant without additional contribution and 14% in the case of a bona fide collaboration with Genevant. Additionally, if Genevant receives proceeds from an action for infringement by any third parties of the Company’s intellectual property licensed to Genevant, the Company would be entitled to receive, after deduction of litigation costs, 20% of the proceeds received by Genevant or, if less, tiered low single-digit royalties on net sales of the infringing product (inclusive of the proceeds from litigation or settlement, which would be treated as net sales).

Leases

Leases	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Leases	Leases The Company had one operating lease for its office and laboratory space as of December 31, 2022. The Company’s corporate headquarters is located at 701 Veterans Circle, Warminster, Pennsylvania. The lease expires on April 30, 2027, and the Company has the option of extending the lease for two further five-year terms. The Company also previously leased office space located at 626 Jacksonville Road, Warminster, Pennsylvania under a lease that terminated on August 31, 2022. The Company accounts for its leases under ASC 842, Leases . Leases with an initial term of 12 months or less are not recorded on the balance sheet. The Company determines if an arrangement is a lease at inception. Right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease right-of-use assets and lease liabilities are recognized based on the present value of lease payments over the lease term. The leases do not provide an implicit rate so in determining the present value of lease payments, the Company utilized its incremental borrowing rate for the applicable lease, which was 9.0% for the 701 Veterans Circle lease and 7.6% for the 626 Jacksonville Road lease. The Company recognizes lease expense on a straight-line basis over the remaining lease term. During each of the years ended December 31, 2022 and 2021, the Company incurred total operating lease expenses of $0.7 million, which included lease expenses associated with fixed lease payments of $0.6 million, and variable payments associated with common area maintenance and similar expenses of $0.1 million. Weighted average remaining lease term and discount rate were as follows: As of December 31, 2022 Weighted-average remaining lease term (years) 4.3 Weighted average discount rate 9.0% The Company did not include options to extend its lease terms as part of its ROU asset and lease liabilities. Supplemental cash flow information related to the Company’s operating leases was as follows: 2022 2021 (in thousands) Cash paid for amounts included in the measurement of lease liabilities $ 641 $ 650 Future minimum lease payments under operating leases that have remaining terms as of December 31, 2022 are as follows: As of December 31, 2022 (in thousands) 2023 $ 598 2024 616 2025 635 2026 654 2027 134 Thereafter — Total lease payments $ 2,637 Less: interest (450) Present value of lease payments $ 2,187

Property and equipment

Property and equipment	12 Months Ended
	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Property and equipment	Property and equipment The Company’s property and equipment balances as of the years ended December 31, 2022 and 2021 are as follows: Cost Accumulated depreciation Net book value December 31, 2022 (in thousands) Lab equipment $ 6,890 $ (5,679) $ 1,211 Leasehold improvements 8,590 (4,749) 3,841 Computer hardware and software 391 (373) 18 $ 15,871 $ (10,801) $ 5,070 Cost Accumulated depreciation Net book value December 31, 2021 (in thousands) Lab equipment $ 6,408 $ (5,178) $ 1,230 Leasehold improvements 8,563 (3,883) 4,680 Computer hardware and software 386 (313) 73 $ 15,357 $ (9,374) $ 5,983

Accounts payable and accrued li

Accounts payable and accrued liabilities	12 Months Ended
	Dec. 31, 2022
Payables and Accruals [Abstract]
Accounts payable and accrued liabilities	Accounts payable and accrued liabilities Accounts payable and accrued liabilities are comprised of the following: December 31, 2022 December 31, 2021 (in thousands) Trade accounts payable $ 3,520 $ 3,174 Payroll accruals 3,730 4,279 Research and development accruals 8,261 2,371 Professional fee accruals 512 983 Other accrued liabilities 6 31 Total $ 16,029 $ 10,838

Sale of future royalties

Sale of future royalties	12 Months Ended
	Dec. 31, 2022
Other Liabilities Disclosure [Abstract]
Sale of future royalties	Sale of future royalties On July 2, 2019, the Company entered into a Purchase and Sale Agreement (the “Agreement”) with the Ontario Municipal Employees Retirement System (“OMERS”), pursuant to which the Company sold to OMERS part of its royalty interest on future global net sales of ONPATTRO, an RNA interference therapeutic currently being sold by Alnylam. ONPATTRO utilizes Arbutus’s LNP technology, which was licensed to Alnylam pursuant to the Cross-License Agreement, dated November 12, 2012, by and between the Company and Alnylam (the “LNP License Agreement”). Under the terms of the LNP License Agreement, the Company is entitled to tiered royalty payments on global net sales of ONPATTRO ranging from 1.00% to 2.33% after offsets, with the highest tier applicable to annual net sales above $500 million. This royalty interest was sold to OMERS, effective as of January 1, 2019, for $20 million in gross proceeds before advisory fees. OMERS will retain this entitlement until it has received $30 million in royalties, at which point 100% of such royalty interest on future global net sales of ONPATTRO will revert to the Company. OMERS has assumed the risk of collecting up to $30 million of future royalty payments from Alnylam and Arbutus is not obligated to reimburse OMERS if they fail to collect any such future royalties. From the inception of the royalty sale through December 31, 2022, an aggregate of $18.9 million of royalties have been collected by OMERS. The $30 million in royalties to be paid to OMERS is accounted for as a liability, with the difference between the liability and the gross proceeds received accounted for as a discount. The discount, as well as $1.5 million of transaction costs, will be amortized as interest expense based on the projected balance of the liability as of the beginning of each period. Management estimated an effective annual interest rate of approximately 8%. Over the course of the Agreement, the actual interest rate will be affected by the amount and timing of royalty revenue recognized and changes in the timing of forecasted royalty revenue. On a quarterly basis, the Company will reassess the expected timing of the royalty revenue, recalculate the amortization and effective interest rate and adjust the accounting prospectively as needed. The Company recognizes non-cash royalty revenue related to the sales of ONPATTRO during the term of the Agreement. As royalties are remitted to OMERS from Alnylam, the balance of the recognized liability is effectively repaid over the life of the Agreement. There are a number of factors that could materially affect the amount and timing of royalty payments from Alnylam, none of which are within the Company’s control. During the year ended December 31, 2022, the Company recognized non-cash royalty revenue of $7.7 million and $1.7 million of related non-cash interest expense. During the year ended December 31, 2021, the Company recognized non-cash royalty revenue of $6.1 million and related non-cash interest expense of $2.9 million. The table below shows the activity related to the net liability for the years ended December 31, 2022 and December 31, 2021: Twelve Months Ended December 31, 2022 2021 (in thousands) Net liability related to sale of future royalties - beginning balance $ 16,296 $ 19,554 Non-cash royalty revenue (7,653) (6,108) Non-cash interest expense 1,722 2,850 Net liability related to sale of future royalties - ending balance $ 10,365 $ 16,296 In addition to the royalty from the LNP License Agreement, the Company is also receiving a second royalty interest ranging from 0.75% to 1.125% on global net sales of ONPATTRO, with 0.75% applying to sales greater than $500 million, originating from a settlement agreement and subsequent license agreement with Acuitas Therapeutics, Inc. (“Acuitas”). The royalty from Acuitas has been retained by the Company and was not part of the royalty sale to OMERS.

Contingencies and commitments

Contingencies and commitments	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Contingencies and commitments	Contingencies and commitments Arbitration with the University of British Columbia Certain early work on lipid nanoparticle delivery systems and related inventions was undertaken at the University of British Columbia (“UBC”), as well as by the Company that was subsequently assigned to UBC. These inventions are licensed to the Company by UBC under a license agreement, initially entered into in 1998 and as amended in 2001, 2006 and 2007. The Company has granted sublicenses under the UBC license to certain third parties, including Alnylam. In November 2014, UBC filed a demand for arbitration against the Company which alleged entitlement to unpaid royalties. In August 2019, the arbitrator issued its decision for the second phase of the arbitration, awarding UBC $5.9 million, which included interest of approximately $2.6 million. The Company paid the $5.9 million award to UBC in September 2019 and paid an additional $0.2 million for costs and attorneys’ fees in March 2021, and this matter is now fully resolved. On December 18, 2020, UBC delivered to the Company a notice of arbitration alleging that under the cross license between UBC and Arbutus, it was due royalties of $2.0 million plus interest arising from the Company’s sale to OMERS of part of its royalty interest on future global net sales of ONPATTRO, currently being sold by Alnylam. Oral hearings for this matter were held in April 2022 and, on July 11, 2022, the arbitrator issued his decision fully dismissing UBC’s claim for royalties. As a result, no payments are owed to UBC. In September 2022, the arbitrator awarded the Company $0.5 million for reimbursement of costs and attorneys’ fees, which the Company received from UBC in October 2022. This matter is now fully resolved. Stock Purchase Agreement with Enantigen In October 2014, Arbutus Inc., the Company’s wholly-owned subsidiary, acquired all of the outstanding shares of Enantigen Therapeutics, Inc. (“Enantigen”) pursuant to a stock purchase agreement. The amount paid to Enantigen’s selling shareholders could be up to an additional $102.5 million in sales performance milestones in connection with the sale of the first commercialized product by Arbutus for the treatment of HBV, regardless of whether such product is based upon assets acquired under this agreement, and a low single-digit royalty on net sales of such first commercialized HBV product, up to a maximum royalty payment of $1.0 million that, if paid, would be offset against Arbutus’ milestone payment obligations. Certain other development milestones related to the acquisition were tied to programs which are no longer under development by Arbutus, and therefore the contingency related to those development milestones is zero. The contingent consideration is a financial liability and is measured at its fair value at each reporting period, with any changes in fair value from the previous reporting period recorded in the statement of operations and comprehensive loss (note 3).

Collaborations and royalty enti

Collaborations and royalty entitlements	12 Months Ended
	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Collaborations and royalty entitlements	Collaborations and royalty entitlements Collaborations Qilu Pharmaceuticals Co, Ltd. In December 2021, the Company entered into a technology transfer and exclusive licensing agreement (the “License Agreement”) with Qilu, pursuant to which the Company granted Qilu an exclusive (except as to certain retained rights), sublicensable, royalty-bearing license, under certain intellectual property owned by the Company, to develop, manufacture and commercialize AB-729, including pharmaceutical products that include AB-729, for the treatment or prevention of hepatitis B in China, Hong Kong, Macau and Taiwan (the “Territory”). In partial consideration for the rights granted by the Company, Qilu paid the Company a one-time upfront cash payment of $40.0 million on January 5, 2022 and agreed to pay the Company milestone payments totaling up to $245 million, net of withholding taxes, upon the achievement of certain technology transfer, development, regulatory and commercialization milestones (the “Milestone Payments”). Qilu paid $4.4 million of withholding taxes to the Chinese taxing authority on the Company’s behalf, related to the upfront cash payment. In addition, Qilu also agreed to pay the Company double digit royalties into the low twenties percent based upon annual net sales of AB-729 in the Territory. The royalties are payable on a product-by-product and region-by-region basis, subject to certain limitations. Qilu is responsible for all costs related to developing, obtaining regulatory approval for, and commercializing AB-729 for the treatment or prevention of hepatitis B in the Territory. Qilu is required to use commercially reasonable efforts to develop, seek regulatory approval for, and commercialize at least one AB-729 product candidate in the Territory. A joint development committee has been established between the Company and Qilu to coordinate and review the development, manufacturing and commercialization plans. Both parties also have entered into a supply agreement and related quality agreement pursuant to which the Company will manufacture or have manufactured and supply Qilu with all quantities of AB-729 necessary for Qilu to develop and commercialize in the Territory until the Company has completed manufacturing technology transfer to Qilu and Qilu has received all approvals required for it or its designated contract manufacturing organization to manufacture AB-729 in the Territory. Concurrent with the execution of the license agreement, the Company entered into a Share Purchase Agreement (the “Share Purchase Agreement”) with Anchor Life Limited, a company established pursuant to the applicable laws and regulations of Hong Kong and an affiliate of Qilu (the “Investor”), pursuant to which the Investor purchased 3,579,952 of the Company’s common shares, without par value (the “Common Shares”), at a purchase price of USD $4.19 per share, which was a 15% premium on the thirty-day average closing price of the Common Shares as of the close of trading on December 10, 2021 (the “Share Transaction”). The Company received $15.0 million of gross proceeds from the Share Transaction on January 6, 2022. The Common Shares sold to the Investor in the Share Transaction represented approximately 2.5% of the Common Shares outstanding immediately prior to the execution of the Share Purchase Agreement. The License Agreement falls under the scope of ASC 808 as both parties are active participants in the arrangement and are exposed to significant risks and rewards. While this arrangement is in the scope of ASC 808, the Company analogizes to ASC 606 for some aspects of this arrangement, including for the delivery of a good or service (i.e., a unit of account). In accordance with the guidance, the Company identified the following commitments under the arrangement: (i) rights to develop, use, sell, have sold, offer for sale and import any product comprised of Licensed Product (the “Qilu License”); and (ii) drug supply obligations and manufacturing technology transfer (the “Manufacturing Obligations”). The Company determined that these two commitments are not distinct performance obligations for purposes of recognizing revenue as the manufacturing process is highly specialized and Qilu would not be able to benefit from the Qilu License without the Company’s involvement in the manufacturing activities until the transfer of the manufacturing know-how is complete. As such, the Company will combine these commitments into one performance obligation to which the transaction price will be allocated to and will recognize this transaction price associated with the bundled performance obligation over time using an inputs method based on labor hours expended by the Company on its Manufacturing Obligations. The Company determined the initial transaction price of the combined performance obligation to be $49.3 million, which includes the $40.0 million upfront fee, $4.4 million of withholding taxes paid by Qilu on behalf of the Company, the premium paid for the Share Transaction of $4.1 million, and $0.8 million associated with certain manufacturing costs expected to be reimbursed by Qilu. The Company determined the Milestone Payments to be variable consideration subject to constraint at inception. At the end of each subsequent reporting period, the Company will reevaluate the probability of achievement of the future development, regulatory, and sales milestones subject to constraint and, if necessary, will adjust its estimate of the overall transaction price. Any such adjustments will be recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. The following table outlines the transaction price and the changes to the related asset and liability balances during the twelve months ended December 31, 2022: Twelve Months Ended December 31, 2022 Transaction Price Cumulative Collaboration Revenue Recognized Deferred License Revenue (in thousands) Combined performance obligation $ 49,270 $ 26,015 $ 23,255 Less contract asset (800) Total deferred license revenue 22,455 Less current portion of deferred license revenue 16,456 Non-current deferred license revenue $ 5,999 The Company recognized $26.0 million of revenue based on labor hours expended by the Company on its Manufacturing Obligations during the twelve months ended December 31, 2022. As of December 31, 2022, the balance of the deferred license revenue was $23.3 million, which, in accordance with ASC 210-20, was partially offset by the contract asset associated with the manufacturing cost reimbursement of $0.8 million, resulting in a net deferred license revenue liability of $22.5 million. The $4.4 million of withholding taxes paid by Qilu on behalf of the Company was recorded as income tax expense during the twelve months ended December 31, 2022. The Company incurred $0.6 million of incremental costs in obtaining the Qilu License, which the Company capitalized in other current assets and other assets and amortizes as a component of general and administrative expense commensurate with the recognition of the combined performance obligation. The Company recognized $0.3 million of related amortization expense for the twelve months ended December 31, 2022. The Company reevaluates the transaction price and the total estimated labor hours expected to be incurred to satisfy the performance obligations and adjusts the deferred revenue at the end of each reporting period. Such changes will result in a change to the amount of collaboration revenue recognized and deferred revenue. Assembly Biosciences, Inc. In August 2020, the Company entered into a clinical collaboration agreement with Assembly Biosciences, Inc. (“Assembly”) to evaluate AB-729 in combination with Assembly’s first-generation HBV core inhibitor (capsid inhibitor) candidate vebicorvir (“VBR”) and standard-of-care NA therapy for the treatment of patients with HBV infection. Assembly has completed enrollment in the clinical trial. In July 2022, Assembly announced its plan to discontinue development of VBR. Despite this, in consultation with Assembly, the Company continued dosing patients in this Phase 2a proof-of-concept clinical trial in order to fully and accurately assess the results. Preliminary data from 65 patients indicated that adding VBR to AB-729 and NA therapy does not positively or negatively impact the reduction of HBsAg compared to AB-729 and NA therapy alone. Accordingly, the Company and Assembly mutually agreed to discontinue the clinical trial following completion of the final, on-treatment visit at week 48. The Company and Assembly shared in the costs of the collaboration. The Company incurred $2.8 million and $2.6 million of costs related to the collaboration during the years ended December 31, 2022 and 2021, respectively, and reflected those costs in research and development in the statements of operations and comprehensive loss. Except to the extent necessary to carry out Assembly’s responsibilities with respect to the collaboration trial, the Company has not provided any license grant to Assembly for use of the Company’s AB-729 compound. Vaccitech plc In July 2021, the Company entered into a clinical collaboration agreement with Vaccitech plc (“Vaccitech”) to evaluate AB-729 followed by Vaccitech’s VTP-300, a proprietary T-cell stimulating antigen-specific immunotherapeutic, in NrtI-suppressed patients with cHBV. The Company is responsible for managing this Phase 2a proof-of-concept clinical trial, subject to oversight by a joint development committee comprised of representatives from the Company and Vaccitech. The Company and Vaccitech retain full rights to their respective product candidates and will split all costs associated with the clinical trial. The Company incurred $0.8 million and $0.5 million of costs related to the collaboration, net of Vaccitech’s 50% share, during the years ended December 31, 2022 and 2021, respectively, and reflected those net costs in research and development in the statements of operations and comprehensive loss. X-Chem, Inc. and Proteros biostructures GmbH In March 2021, the Company entered into a discovery research and license agreement, as amended, with X-Chem, Inc. (“X-Chem”) and Proteros biostructures GmbH (“Proteros”) to focus on the discovery of novel inhibitors targeting the SARS-CoV-2 nsp5 main protease (M pro ). The agreement is designed to accelerate the development of pan-coronavirus agents to treat COVID-19 and potential future coronavirus outbreaks. This collaboration brought together the Company’s expertise in the discovery and development of antiviral agents with X-Chem’s industry leading DNA-encoded library (DEL) technology and Proteros’ protein sciences, biophysics and structural biology capabilities and provides important synergies to potentially identify safe and effective therapies against coronaviruses including SARS-CoV-2. The collaboration allows for the rapid screening of one of the largest small molecule libraries against M pro (an essential protein required for the virus to replicate itself) and the use of state-of-the-art structure guided methods to rapidly optimize M pro inhibitors to progress to clinical candidates. Through this collaboration, the Company has identified and obtained a worldwide exclusive license to several molecules that inhibit M pro , a validated target for the treatment of COVID-19 and potential future coronavirus outbreaks. In the fourth quarter of 2022, the Company nominated AB-343 as its lead candidate that inhibits M pro and the Company is also continuing lead optimization activities for an nsp12 viral polymerase candidate. The agreement provides for payments by the Company to X-Chem and Proteros upon satisfaction of certain development, regulatory and commercial milestones, as well as royalties on sales. The agreement with X-Chem and Proteros was amended effective March 31, 2022 primarily to extend the term of the collaboration and update the funding and fee structure. The Company incurred $1.3 million and $1.9 million of costs related to the collaboration during the years ended December 31, 2022 and 2021, respectively, and reflected those costs in research and development in the statements of operations and comprehensive loss. Royalty Entitlements Alnylam Pharmaceuticals, Inc. and Acuitas Therapeutics, Inc. The Company has two royalty entitlements to Alnylam’s global net sales of ONPATTRO. In 2012, the Company entered into a license agreement with Alnylam Pharmaceuticals, Inc. (“Alnylam”) that entitles Alnylam to develop and commercialize products with the Company’s LNP technology. Alnylam’s ONPATTRO, which represents the first approved application of the Company’s LNP technology, was launched by Alnylam in 2018. Under the terms of this license agreement, the Company is entitled to tiered royalty payments on global net sales of ONPATTRO ranging from 1.00% - 2.33% after offsets, with the highest tier applicable to annual net sales above $500 million. This royalty interest was sold to OMERS, effective as of January 1, 2019, for $20 million in gross proceeds before advisory fees. OMERS will retain this entitlement until it has received $30 million in royalties, at which point 100% of this royalty entitlement on future global net sales of ONPATTRO will revert back to the Company. OMERS has assumed the risk of collecting up to $30.0 million of future royalty payments from Alnylam and the Company is not obligated to reimburse OMERS if they fail to collect any such future royalties. If this royalty entitlement reverts to the Company, it has the potential to provide an active royalty stream or to be otherwise monetized again in full or in part. From the inception of the royalty sale through December 31, 2022, an aggregate of $18.9 million of royalties have been earned by OMERS. See note 9 for further details. The Company also has rights to a second royalty interest ranging from 0.75% to 1.125% on global net sales of ONPATTRO, with 0.75% applying to sales greater than $500 million, originating from a settlement agreement and subsequent license agreement with Acuitas Therapeutics, Inc. (“Acuitas”). This royalty entitlement from Acuitas has been retained by the Company and was not part of the royalty entitlement sale to OMERS. Gritstone Oncology, Inc. On October 16, 2017, the Company entered into a license agreement with Gritstone that granted them worldwide access to its portfolio of proprietary and clinically validated LNP technology and associated intellectual property to deliver Gritstone’s self-replicating, non-mRNA, RNA-based neoantigen immunotherapy products. Gritstone paid the Company an upfront payment, and will make payments for achievement of development, regulatory, and commercial milestones and royalties. As a result of the Company’s agreement with Genevant (see note 5 for details), from April 11, 2018 going forward, Genevant is entitled to 50% of the revenues earned by the Company from Gritstone. The Company is the agent in this arrangement and records revenue on a net basis. Milestone payments that are not within the control of the Company or the licensee, such as those that require regulatory approvals, are not considered probable of being achieved until those approvals are received. The Company did not receive any payments from Gritstone during the years ended December 31, 2022 or 2021. Revenues from the Company’s royalty entitlements are summarized in the following table: Year ended December 31, 2022 2021 (in thousands) Revenue from collaborations and licenses Royalties from sales of Onpattro $ 5,316 $ 4,675 Qilu Pharmaceutical Co., Ltd. 26,015 — Other milestone and royalty payments 35 205 Non-cash royalty revenue Royalties from sales of Onpattro 7,653 6,108 Total revenue $ 39,019 $ 10,988

Shareholders_ equity

Shareholders’ equity	12 Months Ended
	Dec. 31, 2022
Equity [Abstract]
Shareholders' equity	Shareholders’ equity Authorized share capital The Company’s authorized share capital consists of an unlimited number of common shares and preferred shares, without par value, and 1,164,000 Series A participating convertible preferred shares, without par value. Open Market Sale Agreement The Company has an Open Market Sale Agreement with Jefferies LLC (“Jefferies”) dated December 20, 2018, as amended by Amendment No. 1, dated December 20, 2019, Amendment No. 2, dated August 7, 2020 and Amendment No. 3, dated March 4, 2021 (as amended, the “Sale Agreement”), under which the Company may issue and sell common shares, from time to time. On December 23, 2019, the Company filed a shelf registration statement on Form S-3 with the Securities and Exchange Commission (the “SEC”) (File No. 333-235674) and accompanying base prospectus, which was declared effective by the SEC on January 10, 2020 (the “January 2020 Registration Statement”), for the offer and sale of up to $150.0 million of the Company’s securities. The January 2020 Registration Statement also contained a prospectus supplement in connection with the offering of up to $50.0 million of the Company’s common shares pursuant to the Sale Agreement. This prospectus supplement was fully utilized during 2020. On August 7, 2020, the Company filed a prospectus supplement with the SEC (the “August 2020 Prospectus Supplement”) in connection with the offering of up to an additional $75.0 million of its common shares pursuant to the Sale Agreement under the January 2020 Registration Statement. The August 2020 Prospectus Supplement was fully utilized during 2020. On August 28, 2020, the Company filed a shelf registration statement on Form S-3 with the SEC (File No. 333-248467) and accompanying base prospectus, which was declared effective by the SEC on October 22, 2020 (the “October 2020 Registration Statement”), for the offer and sale of up to $200.0 million of the Company’s securities. On March 4, 2021, the Company filed a prospectus supplement with the SEC (the “March 2021 Prospectus Supplement”) in connection with the offering of up to an additional $75.0 million of its common shares pursuant to the Sale Agreement under October 2020 Registration Statement. The March 2021 Prospectus Supplement was fully utilized during 2021. On October 8, 2021, the Company filed a prospectus supplement with the SEC (the “October 2021 Prospectus Supplement”) in connection with the offering of up to an additional $75.0 million of its common shares pursuant to the Sale Agreement under the October 2020 Registration Statement. On November 4, 2021, the Company filed a shelf registration statement on Form S-3 with the SEC (File No. 333-260782) and accompanying base prospectus, declared effective by the SEC on November 18, 2021 (the “November 2021 Registration Statement”), for the offer and sale of up to $250.0 million of the Company’s securities. On March 3, 2022, the Company filed a prospectus supplement with the SEC (the “March 2022 Prospectus Supplement”) in connection with the offering of up to an additional $100.0 million of its common shares pursuant to the Sale Agreement under: (i) the January 2020 Registration Statement; (ii) the October 2020 Registration Statement; and (iii) the November 2021 Registration Statement. During the years ended December 31, 2022 and 2021, the Company issued 8,645,426 and 31,571,036 common shares, respectively, under the Sale Agreement, resulting in net proceeds of approximately $20.3 million and $134.7 million, respectively. As of December 31, 2022, there was approximately $131.1 million remaining available in aggregate under the October 2021 Prospectus Supplement and the March 2022 Prospectus Supplement. Series A Preferred Shares In October 2017, the Company entered into a subscription agreement with Roivant for the sale of Preferred Shares to Roivant for gross proceeds of $116.4 million. The Preferred Shares were non-voting and were convertible into common shares at a conversion price of $7.13 per share (which represented a 15% premium to the closing price of $6.20 per share). The purchase price for the Preferred Shares plus an amount equal to 8.75% per annum, compounded annually, was subject to mandatory conversion into common shares on October 18, 2021, at which time the Preferred Shares were converted into 22,833,922 common shares and both the lockup and standstill periods that Roivant had previously agreed to expired. As of December 31, 2022, Roivant owned approximately 25% of the Company’s outstanding common shares. The Company recorded the Preferred Shares wholly as equity with no bifurcation of conversion feature from the host contract, given that the Preferred Shares could not be cash settled and the redemption features were within the Company’s control, which included a fixed conversion ratio with predetermined timing and proceeds. The Company accrued for the 8.75% per annum

Stock-based compensation

Stock-based compensation	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Stock-based compensation	Stock-based compensation Awards outstanding and available for issuance During the year ended December 31, 2022, the Company had stock options outstanding under the following plans (collectively, the “Plans”): the 2016 Omnibus Share and Incentive Plan (the “2016 Plan”), the 2011 Omnibus Share Compensation Plan (the “2011 Plan”); the 2019 inducement grant; and the OnCore Option Plan. As of December 31, 2022, the aggregate number of shares authorized for awards under all Plans was 28,290,202. As of December 31, 2022, the Company had 15,450,598 options outstanding and 8,842,931 awards available for issuance under the Plans. The Company issues new common shares of stock to settle options exercised. The 2011 Plan expired in June 2021. Under the 2016 Plan, the Company’s board of directors may grant options, and other types of awards, to employees, directors and consultants of the Company. The exercise price of the options is determined by the Company’s board of directors but will be at least equal to the closing market price of the common shares on the date of grant and the term may not exceed 10 years. Options granted generally vest over four years for employees and for directors’ initial grants, and immediately for directors’ annual grants. In June 2019, the Company provided an inducement grant of 1,112,000 options to its newly hired Chief Executive Officer. These options were awarded in a separate plan as non-qualified awards and are governed by the substantially the same terms as the 2016 Plan. Hereafter, information on options governed by the 2016 Plan, the 2011 Plan and the 2019 inducement grant (the “Arbutus Plans”) is presented on a consolidated basis as the terms of the plans are similar. Information on the OnCore Option Plan is presented separately. Stock options under the Arbutus Plans Equity-classified stock options under the Arbutus Plans The following table summarizes activity related to the Company’s equity-classified stock options, including its performance options, for the year ended December 31, 2022: Stock Options Outstanding Vested Stock Options Non-Vested Stock Options Number Weighted-Average Exercise Price Number Number Weighted-Average Grant-Date Fair Value Balance as of December 31, 2021 11,309,974 $ 4.14 6,544,348 4,765,626 $ 2.71 Options granted 4,808,295 $ 2.77 — 4,808,295 $ 2.09 Options exercised (71,025) $ 1.70 (71,025) — $ — Options forfeited, canceled or expired (697,246) $ 3.31 (100,399) (596,847) $ 2.44 Options vested — $ — 3,258,855 (3,258,855) $ 2.42 Balance as of December 31, 2022 15,349,998 $ 3.76 9,631,779 5,718,219 $ 2.39 The intrinsic value of options exercised under the Arbutus Plans during 2022 and 2021 are $0.1 million and $0.2 million, respectively. The following table summarizes additional information related to the Company’s equity-classified stock options, including its performance options, as of December 31, 2022: As of December 31, 2022 Options outstanding and expected to vest Number of stock options outstanding 15,349,998 Weighted-average exercise price $ 3.76 Intrinsic value (in $000s) $ 380 Weighted-average term remaining 7.3 years Vested stock options Number of vested stock options 9,631,779 Weighted-average exercise price $ 4.07 Intrinsic value (in $000s) $ 327 Weighted-average term remaining 6.6 years The assumptions used in the Black-Scholes option-pricing for grants made during the years ended December 31, 2022 and 2021 are as follows: December 31, 2022 December 31, 2021 Expected average option term 5.5 years 5.6 years Expected volatility 97.0 % 93.4 % Expected dividends — % — % Risk-free interest rate 1.77 % 0.67 % The Company considers all available information when estimating the fair value of its stock option grants. Stock options under the other plans As of December 31, 2022, the Company also has 20,000 liability option awards outstanding with a weighted average exercise price of $12.10 and 80,600 stock option awards outstanding under the OnCore Option Plan with a weighted average exercise price of $0.56. Employee Stock Purchase Plan In May 2020, the Company’s stockholders approved the 2020 Employee Stock Purchase Plan (the “ESPP”) which became effective on May 28, 2020. A total of 1,500,000 common shares were reserved for issuance under the ESPP. Company employees contribute funds via payroll deductions, which are used to buy Company common shares at a discount of up to 15% based on the lower of the price at the start of the offering period and at the end of the relevant purchase period within such offering period. The initial offering period under the ESPP was September 1, 2020 through August 31, 2021 with purchase dates set on February 26, 2021 and August 31, 2021, with subsequent offering periods beginning on September 1 and ending on August 31. The Company issued 171,224 and 196,335 shares under its ESPP for the years ended December 31, 2022 and 2021, respectively. As of December 31, 2022, there were 1,132,441 shares remaining for issuance under the ESPP. For the years ended December 31, 2022 and 2021, the Company recognized $0.2 million and $0.3 million, respectively, of stock-based compensation expense related to the ESPP. The fair value of the right to acquire stock at a discounted price under the ESPP is calculated using the Black-Scholes valuation model and recorded as stock-based compensation. Expense is recognized over the period the employee contributes to the plan through payroll deductions. Stock-based compensation expense Total stock-based compensation expense was comprised of: (1) vesting of options awarded to employees under the Arbutus and OnCore Plans calculated in accordance with the fair value method as described above; (2) fair value adjustments for the Company’s liability-classified stock options; and (3) amortization of compensation cost related to the ESPP. The Company recognizes forfeitures as they occur, and the effects of forfeitures are reflected in stock-based compensation expense. Stock-based compensation has been recorded in the consolidated statement of operations and comprehensive loss as follows: Year Ended December 31, 2022 2021 (in thousands) Research and development $ 2,912 $ 2,777 General and administrative 4,270 3,647 Total $ 7,182 $ 6,424 At December 31, 2022, there remained $13.2 million of unrecognized compensation expense related to unvested equity employee stock options to be recognized as expense over a weighted-average period of approximately 2.4 years .

Income taxes

Income taxes	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income taxes	Income taxesThe Company is subject to taxation and files income tax returns in Canadian federal and provincial, United States federal and several state jurisdictions. In December 2022, the United States Internal Revenue service completed its examination of the Company’s federal tax return for 2018. In May 2022, The Canada Revenue Agency completed its examination of the Company’s Canadian tax returns for 2018 and 2019, with no adjustments proposed. Income tax expense varies from the amounts that would be computed by applying the combined Canadian federal and provincial income tax rate of 27% (2021 - 27%) to the loss before income taxes as shown in the following tables: Year ended December 31, 2022 2021 (in thousands) Computed taxes (benefits) at Canadian federal and provincial tax rates $ (17,554) $ (23,864) Withholding taxes 4,444 — Other 761 (1,041) Permanent and other differences 869 4,292 Foreign tax credit applied (4,444) — Federal and Provincial ITCs applied (324) (611) Change in valuation allowance 14,563 15,928 Difference due to income taxed at foreign rates 5,625 4,840 Stock-based compensation 504 456 Income tax expense $ 4,444 $ — As of December 31, 2022, the Company had investment tax credits available to reduce Canadian federal income taxes of $7.2 million, versus $7.4 million as of December 31, 2021, which expire between 2030 and 2037, and provincial income taxes of $2.0 million, versus $2.1 million as of December 31, 2021, which expire between 2024 and 2027. The investment tax credits are accounted for under a flow-through method. In addition, the Company had research and development credits of $3.7 million as of December 31, 2022, and $3.8 million as of December 31, 2021, which expire between 2031 and 2038 and which can be used to reduce future taxable income in the United States. As of December 31, 2022, the Company had scientific research and experimental development expenditures of $62.2 million available for indefinite carry-forward, versus $62.8 million as of December 31, 2021. The Company also had net operating losses of $148.1 million as of December 31, 2022 and $177.7 million as of December 31, 2021, which are due to expire between 2028 and 2038 and which can be used to offset future taxable income in Canada. As of December 31, 2022 and December 31, 2021, the Company had $11.7 million of net operating losses due to expire in 2035 which can be used to offset future taxable income in the United States. Future use of a portion of the United States loss carryforwards are subject to limitations under Internal Revenue Code Section 382. United States net operating loss carryforwards arising in 2019 and future periods have an indefinite carryforward period. As of December 31, 2022 and December 31, 2021, the Company had $203.9 million and $197.8 million, respectively, of total regular net operating losses which can be used to offset future taxable income in the United States. As a result of ownership changes occurring on October 1, 2014 and March 4, 2015, the Company’s ability to use these losses may be limited. Losses incurred to date may be further limited if a subsequent change in control occurs. The Company generated $28.7 million and $93.7 million in pre-tax domestic and foreign losses, respectively, for the year ended December 31, 2022. The Company generated $7.7 million and $80.7 million in pre-tax domestic and foreign losses, respectively, for the year ended December 31, 2021. As required by the 2017 Tax Cuts and Jobs Act and effective in 2022, the deferred tax asset as of December 31, 2022 included $16.5 million related to the mandatory capitalization and amortization of research and development expenses. Significant components of the Company’s deferred tax assets and liabilities are shown below: As of December 31, 2022 2021 (in thousands) Deferred tax assets (liabilities): Non-capital losses carryforwards $ 83,564 $ 90,255 Canadian research and development deductions 16,791 16,968 Book amortization in excess of tax (461) (634) Revenue recognized for tax purposes in excess of revenue recognized for accounting purposes 2,799 4,400 Tax value in excess of accounting value in lease inducements 93 549 Deferred revenue 6,063 — Canadian Federal investment tax credits 5,278 5,301 Canadian Provincial investment tax credits 1,953 2,119 Equity accounted for investment 3,375 3,375 U.S. Federal research and development credits 3,633 3,741 Deductible stock options 3,681 3,309 U.S. research and experimental expenditures capitalization 16,471 — Accrued interest payable 1,507 — Amortization 387 — Other 153 1,341 Total deferred tax assets $ 145,287 $ 130,724 Valuation allowance (145,287) (130,724) Net deferred tax assets (liabilities) $ — $ —

Related party transactions

Related party transactions	12 Months Ended
	Dec. 31, 2022
Related Party Transactions [Abstract]
Related party transactions	Related party transactions Pursuant to a financing and related subscription agreement, the Company issued Roivant the Preferred Shares in October 2017. On October 18, 2021, the Preferred Shares were converted into 22,833,922 common shares. As of December 31, 2022, Roivant owned approximately 25% of the Company’s outstanding common shares. See note 12 for further details. As of December 31, 2022, the carrying value of the Company’s investment in Genevant was zero and the Company owned approximately 16% of the common equity of Genevant. See note 5 for further details.

Significant accounting polici_2

Significant accounting policies (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Basis of presentation	These consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and include the accounts of Arbutus Biopharma Corporation and its one wholly-owned subsidiary, Arbutus Biopharma, Inc.
Principles of consolidation	All intercompany balances and transactions have been eliminated. Certain prior year amounts have been reclassified to conform to the current year presentation. In February 2021, Arbutus Biopharma US Holdings, Inc., which was another wholly-owned subsidiary, merged into Arbutus Biopharma, Inc. with Arbutus Biopharma, Inc. continuing its legal existence and Arbutus Biopharma US Holdings, Inc. ceasing to exist.
Use of estimates	Use of estimates The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions about future events that affect the reported amounts of assets, liabilities, revenue, expenses and contingent liabilities as of the end or during the reporting period. Actual results could significantly differ from those estimates. Significant estimates in the accompanying consolidated financial statements impact contingent consideration, income tax recoveries, stock-based compensation, clinical trial accruals and the sale of future royalties liability.
Cash and cash equivalents	Cash and cash equivalents Cash and cash equivalents are all highly liquid instruments with an original maturity of three months or less when purchased. Cash equivalents are recorded at cost plus accrued interest. The carrying value of these cash equivalents approximates their fair value.
Investments in marketable securities	Investments in marketable securities The Company’s short-term investments consist of marketable securities that have original maturities exceeding three months and remaining maturities of less than one year. The Company classifies investments with remaining maturities of one year or longer as non-current. These investments are accounted for as available-for-sale securities and are reported at fair value, with unrealized gains and losses reported in other comprehensive loss until their disposition. Realized gains and losses from the sale of marketable securities, if any, are calculated using the specific-identification method, and are recorded as a component of other income or loss. The Company reviews its available-for-sale securities at each period end to determine if they remain available-for-sale based on the Company’s current intent and ability to sell the security if it is required to do so. Declines in value judged to be other-than-temporary are included in interest expense in the Company’s statements of operations and comprehensive loss. As of December 31, 2022, the recorded value of the Company’s investments in marketable securities was deemed to be recoverable in all respects. All investments are governed by the Company’s Investment Policy approved by the Company’s board of directors.
Foreign currency translation and functional currency conversion	Foreign currency translation and functional currency conversion The Company’s functional currency is the United States dollar. M onetary assets and liabilities denominated in foreign currencies are translated into United States dollars using exchange rates in effect at the balance sheet date. Opening balances related to non-monetary assets and liabilities are based on prior period translated amounts, and non-monetary assets and non-monetary liabilities are translated at the approximate exchange rate prevailing at the date of the transaction. Revenue and expense transactions are translated at the approximate exchange rate in effect at the time of the transaction. Foreign exchange gains and losses are included in the statement of operations and comprehensive loss as foreign exchange gains or losses.
Investment in Genevant	Investment in GenevantArbutus accounts for its interest in Genevant as equity securities without readily determinable fair values. Accordingly, an estimate of the fair value of the securities is based on the original cost less previously recognized equity method losses, less impairments, plus or minus changes resulting from observable price changes in orderly transactions for identical or similar Genevant securities. As of December 31, 2022, Arbutus owned approximately 16% of the common equity of Genevant and the
Property and equipment	Property and equipment Property and equipment is recorded at cost less impairment losses and accumulated depreciation. The Company records depreciation using the straight-line method over the estimated useful lives of the capital assets as follows: Useful Life (Years) Laboratory equipment 5 Computer and office equipment 2 to 5 Furniture and fixtures 5
Impairment of property and equipment	Property and equipment is reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. If such a review should indicate that the carrying amount of long-lived assets is not recoverable, then such assets are written down to their fair values.
Revenue from collaborations and licenses	Revenue from collaborations and licenses The Company generates revenue primarily through 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, development and manufacturing services. Under such agreements, the Company is generally eligible to receive non-refundable upfront payments, funding for research, development and manufacturing services, milestone payments, and royalties. The Company’s collaboration agreements fall under the scope of 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 606 for some aspects, including for the delivery of a good or service (i.e., a unit of account). ASC 606, Revenue From Contracts with Customers (“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.
Leases	Leases The Company accounts for its lease under ASC 842, Leases
Research and development costs	Research and development costs Research and development costs include compensation and benefits for research and development employees, an allocation of overhead expenses and costs associated with materials and supplies used in clinical trials and research and development, outside contracted services including clinical and pre-clinical study costs, legal, regulatory compliance and fees paid to consultants or outside parties for research and development activities performed on the Company’s behalf. Such costs are charged to expense in the period in which they are incurred.
Net loss attributable to common shareholders per share	Net loss attributable to common shareholders per shareNet loss attributable to common shareholders per share is calculated based on the weighted average number of common shares outstanding. Diluted net loss attributable to common shareholders per share does not differ from basic net loss attributable to common shareholders per share for the years ended December 31, 2022 and 2021, since the effect of including potential common shares would be anti-dilutive.
Deferred income taxes	Deferred income taxes Income taxes are accounted for using the asset and liability method of accounting. Deferred income taxes are recognized for the future income tax consequences attributable to differences between the carrying values of assets and liabilities and their respective income tax bases and for loss carry-forwards. Deferred income tax assets and liabilities are measured using enacted income tax rates expected to apply to taxable income in the periods in which temporary differences are expected to be recovered or settled. The effect on deferred income tax assets and liabilities of a change in tax laws or rates is included in earnings in the period that includes the enactment date. When realization of deferred income tax assets does not meet the more-likely-than-not criterion for recognition, a valuation allowance is provided.
Stock-based compensation	Stock-based compensation The Company measures and recognizes compensation expense for all share-based compensation arrangements based on estimated fair values. The Company uses the Black-Scholes option valuation model to estimate the fair value of stock options at the date of grant. The Black-Scholes option valuation model requires the input of subjective assumptions to calculate the value of stock options. For those assumptions, the Company uses historical data and other information to estimate the expected price volatility and risk free interest rate for all awards. The expected life of stock options granted are estimated to be five years for employees and six years for directors and executives, based on the Company’s historical experience. Assumptions on the dividend yield are based on the fact that the Company has never paid cash dividends and has no present intention to pay cash dividends. Expense is recognized over the vesting period for all awards and commences at the grant date for time-based awards and upon the Company’s determination that the achievement of such performance conditions is probable for performance-based awards. Forfeitures are recognized as they occur. For the Company’s Employee Stock Purchase Plan, the fair value of the right to acquire stock at a discounted price under the plan is calculated using the Black-Scholes valuation model. Expense is recognized over the period the employee contributes to the plan through payroll deductions. The Company accounts for liability-classified stock option awards (“liability options”) under ASC 718 - Compensation - Stock Compensation (“ASC 718”), under which awards of options that provide for an exercise price that is not denominated in: (a) the currency of a market in which a substantial portion of the Company’s equity securities trades, (b) the currency in which the employee’s pay is denominated, or (c) the Company’s functional currency, are required to be classified as liabilities. As of January 1, 2016, the Company changed its functional currency to US dollars, which resulted in certain stock option awards with exercise prices denominated in Canadian dollars having an exercise price that is not denominated in the Company’s functional currency. As such, the historic equity classification of these stock option awards changed to liability classification effective January 1, 2016. The change in classification resulted in reclassification of these awards from additional paid-in capital to a liability.
Preferred Shares	Preferred Shares The Company accounted for its Preferred Shares under ASC 480 – Distinguishing Liabilities from Equity
Segment information	Segment information As of December 31, 2022, the Company viewed its operations and managed its business as one operating segment consistent with how its chief operating decision-maker, the Chief Executive Officer, makes decisions regarding resource allocation and assessing performance. Substantially all of the Company’s premises, property and equipment are located in the United States.
Comprehensive loss	Comprehensive loss Comprehensive loss is comprised of net loss and adjustments for the change in unrealized gains and losses on investments in available-for-sale marketable securities. The Company includes comprehensive loss and its components in the consolidated statements of operations and comprehensive loss, net of tax effects if any.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments which potentially subject the Company to credit risk consist primarily of cash, cash equivalents and marketable securities. The Company holds these investments in highly rated financial institutions, and, by policy, limits the amounts of credit exposure to any one financial institution. These amounts at times may exceed federally insured limits. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to any significant credit risk on these funds. The Company has no off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts or other hedging arrangements.
Recent accounting pronouncements	Recent accounting pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13, Financial Instruments - Credit Losses: Measurement of Credit Losses on 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 financial assets and other instruments that are not measured at fair value through net income, including available-for-sale debt securities. The Company does not anticipate that the new guidance will have a material impact on its results of operations or financial position.

Significant accounting polici_3

Significant accounting policies (Tables)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Schedule of estimated useful lives of property and equipment	The Company records depreciation using the straight-line method over the estimated useful lives of the capital assets as follows: Useful Life (Years) Laboratory equipment 5 Computer and office equipment 2 to 5 Furniture and fixtures 5

Fair value measurements (Tables

Fair value measurements (Tables)	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Schedule of assets and liabilities measured at fair value on a recurring basis	The following tables present information about the Company’s assets and liabilities that are measured at fair value on a recurring basis, and indicates the fair value hierarchy of the valuation techniques used to determine such fair value: Level 1 Level 2 Level 3 Total As of December 31, 2022 (in thousands) Assets Cash and cash equivalents $ 30,776 $ — $ — $ 30,776 Investments in marketable securities, current — 116,137 — 116,137 Investments in marketable securities, non-current — 37,363 — 37,363 Total $ 30,776 $ 153,500 $ — $ 184,276 Liabilities Liability-classified options $ — $ — $ 1 $ 1 Contingent consideration — — 7,531 7,531 Total $ — $ — $ 7,532 $ 7,532 Level 1 Level 2 Level 3 Total As of December 31, 2021 (in thousands) Assets Cash and cash equivalents $ 109,282 $ — $ — $ 109,282 Investments in marketable securities, current — 46,035 — 46,035 Investments in marketable securities, non-current — 35,688 — 35,688 Total $ 109,282 $ 81,723 $ — $ 191,005 Liabilities Liability-classified options $ — $ — $ 26 $ 26 Contingent consideration — — 5,298 5,298 Total $ — $ — $ 5,324 $ 5,324
Schedule of changes in fair value of liability-classified stock options	The following table presents the changes in fair value of the Company’s liability-classified stock option awards: Liability at beginning of the period Fair value of liability-classified options exercised in the period Decrease in fair value of liability Liability at end of the period (in thousands) Year ended December 31, 2022 $ 26 $ — $ (25) $ 1 Year ended December 31, 2021 $ 250 $ (96) $ (128) $ 26
Schedule of changes in fair value of contingent consideration	The following table presents the changes in fair value of the Company’s contingent consideration: Liability at beginning of the period Increase in fair value of liability Liability at end of the period (in thousands) Year ended December 31, 2022 $ 5,298 $ 2,233 $ 7,531 Year ended December 31, 2021 $ 3,426 $ 1,872 $ 5,298

Investments in marketable sec_2

Investments in marketable securities (Tables)	12 Months Ended
	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Investments in marketable securities	Investments in marketable securities and cash equivalents consisted of the following: Amortized Cost Gross Unrealized Gain (1) Gross Unrealized Loss (1) Fair Value As of December 31, 2022 (in thousands) Cash equivalents Money market fund $ 23,218 $ — $ — $ 23,218 Total $ 23,218 $ — $ — $ 23,218 Investments in marketable short-term securities US government agency bonds $ 26,686 $ — $ (424) $ 26,262 US corporate bonds 27,144 — (303) 26,841 US treasury bills 8,483 — (16) 8,467 US government bonds 55,361 — (794) 54,567 Total $ 117,674 $ — $ (1,537) $ 116,137 Investments in marketable long-term securities US government agency bonds $ 3,724 $ — $ (130) $ 3,594 US corporate bonds 25,433 — (336) 25,097 US government bonds 8,972 — (300) 8,672 Total $ 38,129 $ — $ (766) $ 37,363 (1) Gross unrealized gain (loss) is pre-tax and is reported in accumulated other comprehensive loss. Amortized Cost Gross Unrealized Gain (1) Gross Unrealized Loss (1) Fair Value As of December 31, 2021 (in thousands) Cash equivalents Money market fund $ 93,211 $ — $ — $ 93,211 Total $ 93,211 $ — $ — $ 93,211 Investments in marketable short-term securities US government agency bonds $ 8,131 $ — $ (11) $ 8,120 US government bonds 37,968 — (53) 37,915 Total $ 46,099 $ — $ (64) $ 46,035 Investments in marketable long-term securities US government agency bonds $ 13,068 $ — $ (29) $ 13,039 US treasury bills 22,707 — (58) 22,649 Total $ 35,775 $ — $ (87) $ 35,688 (1) Gross unrealized gain (loss) is pre-tax and is reported in accumulated other comprehensive loss.

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Schedule of lease cost	Weighted average remaining lease term and discount rate were as follows: As of December 31, 2022 Weighted-average remaining lease term (years) 4.3 Weighted average discount rate 9.0% The Company did not include options to extend its lease terms as part of its ROU asset and lease liabilities. Supplemental cash flow information related to the Company’s operating leases was as follows: 2022 2021 (in thousands) Cash paid for amounts included in the measurement of lease liabilities $ 641 $ 650
Schedule of lease maturity	Future minimum lease payments under operating leases that have remaining terms as of December 31, 2022 are as follows: As of December 31, 2022 (in thousands) 2023 $ 598 2024 616 2025 635 2026 654 2027 134 Thereafter — Total lease payments $ 2,637 Less: interest (450) Present value of lease payments $ 2,187

Property and equipment (Tables)

Property and equipment (Tables)	12 Months Ended
	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Schedule of property and equipment	The Company’s property and equipment balances as of the years ended December 31, 2022 and 2021 are as follows: Cost Accumulated depreciation Net book value December 31, 2022 (in thousands) Lab equipment $ 6,890 $ (5,679) $ 1,211 Leasehold improvements 8,590 (4,749) 3,841 Computer hardware and software 391 (373) 18 $ 15,871 $ (10,801) $ 5,070 Cost Accumulated depreciation Net book value December 31, 2021 (in thousands) Lab equipment $ 6,408 $ (5,178) $ 1,230 Leasehold improvements 8,563 (3,883) 4,680 Computer hardware and software 386 (313) 73 $ 15,357 $ (9,374) $ 5,983

Accounts payable and accrued _2

Accounts payable and accrued liabilities (Tables)	12 Months Ended
	Dec. 31, 2022
Payables and Accruals [Abstract]
Schedule of accounts payable and accrued liabilities	Accounts payable and accrued liabilities are comprised of the following: December 31, 2022 December 31, 2021 (in thousands) Trade accounts payable $ 3,520 $ 3,174 Payroll accruals 3,730 4,279 Research and development accruals 8,261 2,371 Professional fee accruals 512 983 Other accrued liabilities 6 31 Total $ 16,029 $ 10,838

Sale of future royalties (Table

Sale of future royalties (Tables)	12 Months Ended
	Dec. 31, 2022
Other Liabilities Disclosure [Abstract]
Activity related to net liability	The table below shows the activity related to the net liability for the years ended December 31, 2022 and December 31, 2021: Twelve Months Ended December 31, 2022 2021 (in thousands) Net liability related to sale of future royalties - beginning balance $ 16,296 $ 19,554 Non-cash royalty revenue (7,653) (6,108) Non-cash interest expense 1,722 2,850 Net liability related to sale of future royalties - ending balance $ 10,365 $ 16,296

Collaborations and royalty en_2

Collaborations and royalty entitlements (Tables)	12 Months Ended
	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Schedule of revenue recognized under collaborations, contracts and licensing agreements	Revenues from the Company’s royalty entitlements are summarized in the following table: Year ended December 31, 2022 2021 (in thousands) Revenue from collaborations and licenses Royalties from sales of Onpattro $ 5,316 $ 4,675 Qilu Pharmaceutical Co., Ltd. 26,015 — Other milestone and royalty payments 35 205 Non-cash royalty revenue Royalties from sales of Onpattro 7,653 6,108 Total revenue $ 39,019 $ 10,988

Stock-based compensation (Table

Stock-based compensation (Tables)	12 Months Ended
	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of allocation of stock-based compensation	Stock-based compensation has been recorded in the consolidated statement of operations and comprehensive loss as follows: Year Ended December 31, 2022 2021 (in thousands) Research and development $ 2,912 $ 2,777 General and administrative 4,270 3,647 Total $ 7,182 $ 6,424
Liability classified stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of stock option activity
Arbutus Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of stock option activity	The following table summarizes activity related to the Company’s equity-classified stock options, including its performance options, for the year ended December 31, 2022: Stock Options Outstanding Vested Stock Options Non-Vested Stock Options Number Weighted-Average Exercise Price Number Number Weighted-Average Grant-Date Fair Value Balance as of December 31, 2021 11,309,974 $ 4.14 6,544,348 4,765,626 $ 2.71 Options granted 4,808,295 $ 2.77 — 4,808,295 $ 2.09 Options exercised (71,025) $ 1.70 (71,025) — $ — Options forfeited, canceled or expired (697,246) $ 3.31 (100,399) (596,847) $ 2.44 Options vested — $ — 3,258,855 (3,258,855) $ 2.42 Balance as of December 31, 2022 15,349,998 $ 3.76 9,631,779 5,718,219 $ 2.39 The following table summarizes additional information related to the Company’s equity-classified stock options, including its performance options, as of December 31, 2022: As of December 31, 2022 Options outstanding and expected to vest Number of stock options outstanding 15,349,998 Weighted-average exercise price $ 3.76 Intrinsic value (in $000s) $ 380 Weighted-average term remaining 7.3 years Vested stock options Number of vested stock options 9,631,779 Weighted-average exercise price $ 4.07 Intrinsic value (in $000s) $ 327 Weighted-average term remaining 6.6 years
Schedule of weighted average Black-Scholes option-pricing assumptions and resultant fair values	The assumptions used in the Black-Scholes option-pricing for grants made during the years ended December 31, 2022 and 2021 are as follows: December 31, 2022 December 31, 2021 Expected average option term 5.5 years 5.6 years Expected volatility 97.0 % 93.4 % Expected dividends — % — % Risk-free interest rate 1.77 % 0.67 %

Income taxes (Tables)

Income taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Schedule of effective income tax rate reconciliation	Income tax expense varies from the amounts that would be computed by applying the combined Canadian federal and provincial income tax rate of 27% (2021 - 27%) to the loss before income taxes as shown in the following tables: Year ended December 31, 2022 2021 (in thousands) Computed taxes (benefits) at Canadian federal and provincial tax rates $ (17,554) $ (23,864) Withholding taxes 4,444 — Other 761 (1,041) Permanent and other differences 869 4,292 Foreign tax credit applied (4,444) — Federal and Provincial ITCs applied (324) (611) Change in valuation allowance 14,563 15,928 Difference due to income taxed at foreign rates 5,625 4,840 Stock-based compensation 504 456 Income tax expense $ 4,444 $ —
Schedule of components of deferred tax assets	Significant components of the Company’s deferred tax assets and liabilities are shown below: As of December 31, 2022 2021 (in thousands) Deferred tax assets (liabilities): Non-capital losses carryforwards $ 83,564 $ 90,255 Canadian research and development deductions 16,791 16,968 Book amortization in excess of tax (461) (634) Revenue recognized for tax purposes in excess of revenue recognized for accounting purposes 2,799 4,400 Tax value in excess of accounting value in lease inducements 93 549 Deferred revenue 6,063 — Canadian Federal investment tax credits 5,278 5,301 Canadian Provincial investment tax credits 1,953 2,119 Equity accounted for investment 3,375 3,375 U.S. Federal research and development credits 3,633 3,741 Deductible stock options 3,681 3,309 U.S. research and experimental expenditures capitalization 16,471 — Accrued interest payable 1,507 — Amortization 387 — Other 153 1,341 Total deferred tax assets $ 145,287 $ 130,724 Valuation allowance (145,287) (130,724) Net deferred tax assets (liabilities) $ — $ —

Organization (Details)

Organization (Details) - USD ($)	Jan. 05, 2022	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash, cash equivalents and short-term investments		$ 184,300,000
Outstanding debt		$ 0
One-Time Upfront Cash Payment | Qilu
Class of Stock [Line Items]
Cash payment for collaborations	$ 40,000,000

Significant accounting polici_4

Significant accounting policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2022 USD ($) subsidiary shares	Dec. 31, 2021 shares	Oct. 18, 2021 shares
Accounting Policies [Abstract]
Number of wholly-owned subsidiaries | subsidiary	1
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Equity method investments | $	$ 0
Anti-dilutive common shares excluded from calculation of income per common share (in shares)		11,400,000
Outstanding preferred shares that converted to common shares (in shares)			22,833,922
Preferred dividend percentage	8.75%
Stock Option | Directors and Executives
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Expected life	6 years
Stock Option | Employee
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Expected life	5 years
Stock Option
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Anti-dilutive common shares excluded from calculation of income per common share (in shares)	15,500,000
Genevant
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Ownership interest in equity method investment (as a percent)	16%
Equity method investments | $	$ 0

Significant accounting polici_5

Significant accounting policies - Estimated useful lives of property and equipment (Details)	12 Months Ended
	Dec. 31, 2022
Laboratory equipment
Property, Plant and Equipment [Line Items]
Useful lives	5 years
Computer and office equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful lives	2 years
Computer and office equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful lives	5 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful lives	5 years

Significant accounting polici_6

Significant accounting policies - Computation of basic and diluted net income (loss) per common share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dividend accretion of convertible preferred shares	$ 0	$ (12,139)
Net loss attributable to common shares	$ (69,456)	$ (88,386)
Weighted average number of common shares - basic (in shares)	150,939,337	106,242,452
Weighted average number of common shares - diluted (in shares)	150,939,337	106,242,452
Basic net loss attributable to common shareholders per share (in USD per share)	$ (0.46)	$ (0.83)
Diluted net loss attributable to common shareholders per share (in USD per share)	$ (0.46)	$ (0.83)

Fair value measurements_ - Narr

Fair value measurements  - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair value of contingent consideration	$ 7,531	$ 5,298	$ 3,426
Increase in fair value of contingent consideration	$ 2,233	$ 1,872

Fair value measurements_ - Asse

Fair value measurements  - Assets and liabilities measured at fair value on recurring basis (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Liabilities
Contingent consideration	$ 7,531	$ 5,298	$ 3,426
Investments in marketable securities, non-current	37,363	35,688
Fair Value, Measurements, Recurring
Assets
Cash and cash equivalents	30,776	109,282
Investments in marketable securities, current	116,137	46,035
Total	184,276	191,005
Liabilities
Liability-classified options	1	26
Contingent consideration	7,531	5,298
Total	7,532	5,324
Investments in marketable securities, non-current	37,363	35,688
Fair Value, Measurements, Recurring | Level 1
Assets
Cash and cash equivalents	30,776	109,282
Investments in marketable securities, current	0	0
Total	30,776	109,282
Liabilities
Liability-classified options	0	0
Contingent consideration	0	0
Total	0	0
Investments in marketable securities, non-current	0	0
Fair Value, Measurements, Recurring | Level 2
Assets
Cash and cash equivalents	0	0
Investments in marketable securities, current	116,137	46,035
Total	153,500	81,723
Liabilities
Liability-classified options	0	0
Contingent consideration	0	0
Total	0	0
Investments in marketable securities, non-current	37,363	35,688
Fair Value, Measurements, Recurring | Level 3
Assets
Cash and cash equivalents	0	0
Investments in marketable securities, current	0	0
Total	0	0
Liabilities
Liability-classified options	1	26
Contingent consideration	7,531	5,298
Total	7,532	5,324
Investments in marketable securities, non-current	$ 0	$ 0

Fair value measurements_ - Chan

Fair value measurements  - Changes in fair value of liabilities - classified as stock option (Details) - Liability classified stock options - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Liabilities Measured on Recurring Basis [Roll Forward]
Liability at beginning of the period	$ 26	$ 250
Fair value of liability-classified options exercised in the period	0	(96)
Decrease in fair value of liability	(25)	(128)
Liability at end of the period	$ 1	$ 26

Fair value measurements_- Chang

Fair value measurements - Changes in fair value of contingent consideration (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Liabilities Measured on Recurring Basis [Roll Forward]
Liability at beginning of the period	$ 5,298	$ 3,426
Increase in fair value of liability	2,233	1,872
Liability at end of the period	$ 7,531	$ 5,298

Investments in marketable sec_3

Investments in marketable securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Cash Equivalents, Amortized Cost	$ 30,776	$ 109,282
Fair Value	116,100
Debt Securities, Available-for-Sale, Amortized Cost, Noncurrent	38,129	35,775
Debt Securities, Noncurrent	(37,400)	(35,700)
Debt Securities, Realized Gain (Loss)	100	0
Short-Term Investments
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, Current	117,674	46,099
Gross Unrealized Gain	0
Gross Unrealized Loss	(1,537)	(64)
Fair Value	116,137	46,035
Long-Term Investments
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gain	0
Gross Unrealized Loss	(766)	(87)
Debt Securities, Noncurrent	(37,363)	(35,688)
Money market fund
Debt Securities, Available-for-sale [Line Items]
Cash Equivalents, Amortized Cost	23,218	93,211
Cash Equivalents, Fair Value	23,218	93,211
US government agency bonds
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, Noncurrent	3,724	13,068
US government agency bonds | Short-Term Investments
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, Current	26,686	8,131
Gross Unrealized Gain	0	0
Gross Unrealized Loss	(424)	(11)
Fair Value	26,262	8,120
US government agency bonds | Long-Term Investments
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gain	0	0
Gross Unrealized Loss	(130)	(29)
Debt Securities, Noncurrent	(3,594)	(13,039)
US corporate bonds
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, Noncurrent	25,433
US corporate bonds | Short-Term Investments
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, Current	27,144
Gross Unrealized Gain	0
Gross Unrealized Loss	(303)
Fair Value	26,841
US corporate bonds | Long-Term Investments
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gain	0
Gross Unrealized Loss	(336)
Debt Securities, Noncurrent	(25,097)
US treasury bills
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, Noncurrent		22,707
US treasury bills | Short-Term Investments
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, Current	8,483
Gross Unrealized Gain	0
Gross Unrealized Loss	(16)
Fair Value	8,467
US treasury bills | Long-Term Investments
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gain	0
Gross Unrealized Loss		(58)
Debt Securities, Noncurrent		(22,649)
US government bonds
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, Noncurrent	8,972
US government bonds | Short-Term Investments
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost, Current	55,361	37,968
Gross Unrealized Gain	0
Gross Unrealized Loss	(794)	(53)
Fair Value	54,567	$ 37,915
US government bonds | Long-Term Investments
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gain	0
Gross Unrealized Loss	(300)
Debt Securities, Noncurrent	$ (8,672)

Investment in Genevant (Details

Investment in Genevant (Details)	12 Months Ended
	Dec. 31, 2022 USD ($)
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 0
Genevant
Schedule of Equity Method Investments [Line Items]
Sub-licensing revenue, percentage	20%
Bona fide collaboration Percentage [Member]	14%
Equity method investments	$ 0
Ownership interest in equity method investment (as a percent)	16%

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) lease renewal_option	Dec. 31, 2021 USD ($)
Lessee, Lease, Description [Line Items]
Number of operating leases | lease	1
Renewal term	5 years
Operating lease expense	$ 0.7	$ 0.7
Fixed lease payment	0.6	0.6
Variable lease payment	$ 0.1	$ 0.1
Corporate Headquarters Located 701 Veterans Circle, Warminster, Pennsylvania
Lessee, Lease, Description [Line Items]
Number of renewal options | renewal_option	2
Discount rate	9%
Offices Located at 626 Jacksonville Rd., Warminster, Pennsylvania
Lessee, Lease, Description [Line Items]
Discount rate	7.60%

Leases - Lease cost (Details)

Leases - Lease cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Weighted-average remaining lease term (years)	4 years 3 months 18 days
Weighted average discount rate	9%
Cash paid for amounts included in the measurement of lease liabilities	$ 641	$ 650

Leases - Maturity of lease liab

Leases - Maturity of lease liability (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Leases [Abstract]
2023	$ 598
2024	616
2025	635
2026	654
2027	134
Thereafter	0
Total lease payments	2,637
Less: interest	(450)
Present value of lease payments	$ 2,187

Property and equipment (Details

Property and equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Cost	$ 15,871	$ 15,357
Accumulated depreciation	(10,801)	(9,374)
Net book value	5,070	5,983
Depreciation	1,427	1,753
Lab equipment
Property, Plant and Equipment [Line Items]
Cost	6,890	6,408
Accumulated depreciation	(5,679)	(5,178)
Net book value	1,211	1,230
Leasehold improvements
Property, Plant and Equipment [Line Items]
Cost	8,590	8,563
Accumulated depreciation	(4,749)	(3,883)
Net book value	3,841	4,680
Computer hardware and software
Property, Plant and Equipment [Line Items]
Cost	391	386
Accumulated depreciation	(373)	(313)
Net book value	$ 18	$ 73

Accounts payable and accrued _3

Accounts payable and accrued liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Trade accounts payable	$ 3,520	$ 3,174
Payroll accruals	3,730	4,279
Research and development accruals	8,261	2,371
Professional fee accruals	512	983
Other accrued liabilities	6	31
Accounts payable and accrued liabilities	$ 16,029	$ 10,838

Sale of future royalties - Narr

Sale of future royalties - Narrative (Details) - USD ($)			12 Months Ended		42 Months Ended
	Jul. 02, 2019	Jan. 01, 2019	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022
Other Liabilities Disclosure [Line Items]
Non-cash royalty revenue			$ 7,653,000	$ 6,108,000
Non-cash interest expense			$ 1,722,000	2,850,000
Minimum
Other Liabilities Disclosure [Line Items]
Royalty interest, Percent interest			75%
Maximum
Other Liabilities Disclosure [Line Items]
Royalty interest, Percent interest			112.50%
OMERS
Other Liabilities Disclosure [Line Items]
Royalty interest sold, percentage of sales, annual revenue threshold of highest tier	$ 500,000,000
Gross proceeds from royalty interest sold		$ 20,000,000
Royalty interest sold, maximum royalties for buyer	$ 30,000,000
Royalty guarantees commitments percentage	100%
Royalty payable	$ 30,000,000
Non-cash royalty revenue			$ 7,700,000	6,100,000	$ 18,900,000
Transaction costs related to sale of future royalties	$ 1,500,000
Effective annual interest rate of royalty liability			8%
Non-cash interest expense			$ 1,700,000	$ 2,900,000
OMERS | Minimum
Other Liabilities Disclosure [Line Items]
Royalty, percentage of interest sold	1%
Royalty interest, Percent interest			0.75%
OMERS | Maximum
Other Liabilities Disclosure [Line Items]
Royalty, percentage of interest sold	2.33%
Royalty interest, Percent interest			1.125%

Sale of future royalties - Acti

Sale of future royalties - Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Liability Related To Future Royalties [Roll Forward]
Net liability related to sale of future royalties - beginning balance	$ 16,296	$ 19,554
Non-cash royalty revenue	(7,653)	(6,108)
Non-cash interest expense	1,722	2,850
Net liability related to sale of future royalties - ending balance	10,365	$ 16,296
ONPATTRO, global net sales [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Annual Revenue Threshold	500,000
Annual Revenue Threshold	$ 500,000

Contingencies and commitments (

Contingencies and commitments (Details) - USD ($) $ in Thousands			1 Months Ended		12 Months Ended
	Dec. 18, 2020	Aug. 20, 2019	Mar. 31, 2021	Sep. 30, 2019	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Oct. 31, 2014
Contingencies and Commitments [Line Items]
Contingent consideration					$ 7,531	$ 5,298	$ 3,426
Fair Value, Measurements, Recurring
Contingencies and Commitments [Line Items]
Contingent consideration					7,531	$ 5,298
Fair Value, Measurements, Recurring | Enantigen's Selling Shareholders
Contingencies and Commitments [Line Items]
Contingent consideration					7,500
Blumberg and Drexel | Fair Value, Measurements, Recurring | Enantigen
Contingencies and Commitments [Line Items]
Contingent consideration					0
Blumberg and Drexel | Arbutus Inc.
Contingencies and Commitments [Line Items]
Development and regulatory milestones payment per licensed compound series, maximum								$ 102,500
Maximum royalty payment								$ 1,000
Arbitration with the University of British Columbia
Contingencies and Commitments [Line Items]
Payments for legal settlements		$ 5,900		$ 5,900
Litigation settlement interest		$ 2,600
Loss contingency, damages sought for allegedly unpaid royalties	$ 2,000
Loss Contingency, Damages Awarded, Value					$ 500
Arbitration with the University of British Columbia | Minimum
Contingencies and Commitments [Line Items]
Legal Fees			$ 200

Collaborations and royalty en_3

Collaborations and royalty entitlements - Narrative (Details)					12 Months Ended		42 Months Ended
	Jan. 06, 2022 USD ($)	Jan. 05, 2022 USD ($)	Jul. 02, 2019 USD ($)	Jan. 01, 2019 USD ($)	Dec. 31, 2022 USD ($) product shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2022 USD ($) product shares	Dec. 13, 2021 USD ($) $ / shares shares	Apr. 11, 2018
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Common shares, shares issued (in shares) | shares					157,455,363	144,987,736	157,455,363
Number of royalty entitlements | product					2		2
Non-cash royalty revenue					$ 7,653,000	$ 6,108,000
Total revenue					39,019,000	10,988,000
License
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Equity method investment, percentage or revenue entitled									50%
Non-cash royalty revenue
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total revenue					7,653,000	6,108,000
Common Shares | Qilu
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners								2.50%
Qilu
Research and Development Arrangement, Contract to Perform for Others [Line Items]
License Agreement Milestone payment maximum								$ 245,000,000
Qilu | Common Shares
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Common shares, shares issued (in shares) | shares								3,579,952
Shares price (in USD per share) | $ / shares								$ 4.19
Premium percentage on closing stock price								15%
Issuance of common shares pursuant to Share Purchase Agreement	$ 15,000,000
Qilu | One-Time Upfront Cash Payment
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Cash payment for collaborations		$ 40,000,000
Assembly
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Costs related to collaboration					2,800,000	2,600,000
Vaccitech
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Costs related to collaboration					$ 800,000	500,000
Percent of Costs related to Collaboration					50%
OMERS
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty interest sold, percentage of sales, annual revenue threshold of highest tier			$ 500,000,000
Gross proceeds from royalty interest sold				$ 20,000,000
Royalty interest sold, maximum royalties for buyer			$ 30,000,000
Royalty guarantees commitments percentage			100%
Royalty payable			$ 30,000,000
Non-cash royalty revenue					$ 7,700,000	6,100,000	$ 18,900,000
OMERS | Minimum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty, percentage of interest sold			1%
OMERS | Maximum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty, percentage of interest sold			2.33%
Onpattro - Cash Royalty [Member] | License
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total revenue					5,316,000	4,675,000
Qilu Pharmaceutical Co, LTD. | License
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total revenue					26,015,000	0
Qilu Pharmaceutical Co, LTD. | One-Time Upfront Cash Payment
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Cash payment for collaborations					40,000,000
Other Milestones and Royalty Payments [Member] | License
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total revenue					35,000	205,000
Onpattro - Non-cash Royalty [Member] | Non-cash royalty revenue
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total revenue					$ 7,653,000	$ 6,108,000

Collaborations and royalty en_4

Collaborations and royalty entitlements - Summary of revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 13, 2021
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total deferred revenue	$ 22,455
Deferred Revenue, Current	16,456	$ 0
Deferred Revenue, Noncurrent	5,999	0
Total revenue	$ 39,019	10,988
Minimum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty interest, Percent interest	75%
Qilu Pharmaceutical Co, LTD.
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Deferred Revenue, Noncurrent	$ 5,999
Qilu Pharmaceutical Co, LTD.
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue, Remaining Performance Obligation, Amount	23,255		$ 49,270
Income Taxes Paid	4,400
Premiums Earned, Net	4,100
Recovery of Direct Costs	800
Contract with Customer, Liability, Revenue Recognized	26,015
Total deferred revenue	22,500
Deferred Revenue, Current	16,456
Other Deferred Costs, Gross	600
Amortization of Other Deferred Charges	300
Qilu Pharmaceutical Co, LTD. | License
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total revenue	26,015	0
Qilu Pharmaceutical Co, LTD. | One-Time Upfront Cash Payment
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Cash payment for collaborations	40,000
Onpattro - Cash Royalty [Member] | License
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total revenue	5,316	4,675
Other Milestones and Royalty Payments [Member] | License
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Total revenue	35	205
Vaccitech
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Costs related to collaboration	800	500
Costs related to collaboration	800	500
X-Chem, Inc. and Proteros
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Costs related to collaboration	1,300	1,900
Costs related to collaboration	1,300	$ 1,900
ONPATTRO, global net sales [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Annual Revenue Threshold	$ 500,000
OMERS | Minimum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty interest, Percent interest	0.75%

Shareholders_ equity (Details)

Shareholders’ equity (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Oct. 02, 2017	Dec. 31, 2022	Dec. 31, 2021	Mar. 03, 2022	Nov. 04, 2021	Oct. 18, 2021	Oct. 08, 2021	Mar. 04, 2021	Oct. 22, 2020	Aug. 07, 2020	Jan. 10, 2020
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		1,164,000
Preferred dividend percentage		8.75%
Outstanding preferred shares that converted to common shares (in shares)						22,833,922
Common Shares | Jan 2020 Registration Stmt
Class of Stock [Line Items]
Aggregate share sales price											$ 150
Common Shares | Oct 2020 Registration Stmt
Class of Stock [Line Items]
Aggregate share sales price									$ 200
Common Shares | Nov 2021 Registration Stmt
Class of Stock [Line Items]
Aggregate share sales price					$ 250
Jefferies LLC | Common Shares | October 2021 Prospectus Supplement | Oct 2020 Registration Stmt
Class of Stock [Line Items]
Aggregate share sales price							$ 75
Jefferies LLC | Common Shares | Sale Agreement
Class of Stock [Line Items]
Number of shares issued under agreement		8,645,426	31,571,036
Proceeds from issuance of common stock		$ 20.3	$ 134.7
Jefferies LLC | Common Shares | Aug 2020 Prospectus Supplement | Jan 2020 Registration Stmt
Class of Stock [Line Items]
Aggregate share sales price										$ 75
Jefferies LLC | Common Shares | Mar 2021 Prospectus Supplement Agreement | Oct 2020 Registration Stmt
Class of Stock [Line Items]
Aggregate share sales price								$ 75
Jefferies LLC | Common Shares | March 2022 Prospectus Supplement
Class of Stock [Line Items]
Aggregate share sales price		$ 131.1
Jefferies LLC | Common Shares | March 2022 Prospectus Supplement | Jan 2020 Oct 2020 and Nov 2021 Registration Stmts
Class of Stock [Line Items]
Aggregate share sales price				$ 100
Jefferies LLC | Common Shares | Jan 2020 Prospectus Supplement | Jan 2020 Registration Stmt
Class of Stock [Line Items]
Aggregate share sales price											$ 50
Roivant
Class of Stock [Line Items]
Noncontrolling interest, ownership percentage by owners after conversion		25%
Roivant | Convertible Preferred Stock
Class of Stock [Line Items]
Issuance of common shares in conjunction with the private offering, net of issuance costs	$ 116.4
Preferred stock, par value (in USD per share)	$ 7.13
Premium percentage on closing stock price	15%
Shares price (in USD per share)	$ 6.20
Preferred dividend percentage	8.75%

Stock-based compensation - Narr

Stock-based compensation - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares reserved for issuance		1,500,000
Discount rate on shares		15%
Issuance of common shares pursuant to exercise of ESPP options (in shares)		171,224	196,335
Number of shares remaining for issuance		1,132,441
Stock-based compensation expense related to ESPP		$ 200	$ 300
Unearned compensation expense		$ 13,200
Unearned compensation expense, recognition period		2 years 4 months 24 days
Stock-based compensation expense		$ 7,182	$ 6,424
Collier Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	1,112,000
Arbutus Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life		5 years 6 months	5 years 7 months 6 days
Intrinsic value of options exercised		$ 100	$ 200
OnCore Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding (in shares)		80,600
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock-based compensation awards approved to be issued (in shares)		28,290,202
Number of options outstanding (in shares)		15,450,598
Number of additional shares authorized (in shares)		8,842,931
Stock options | 2016 and 2011 Plans | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life		10 years
Stock options | 2016 and 2011 Plans | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option vesting period		4 years
Liability classified stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding (in shares)		20,000
Performance shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 0	$ 0

Stock-based compensation - Stoc

Stock-based compensation - Stock option activity under the Arbutus Plan (Details) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Weighted average exercise price
Issuance of common shares pursuant to exercise of ESPP options (in shares)	171,224	196,335
Arbutus Plans | Stock Options
Number of optioned common shares
Balance - Number of optioned common shares (in shares)	11,309,974
Options granted (in shares)	4,808,295
Options exercised (in shares)	(71,025)
Options forfeited, canceled or expired (in shares)	(697,246)
Options vested (in shares)	0
Balance - Number of optioned common shares (in shares)	15,349,998	11,309,974
Weighted average exercise price
Balance - Weighted average exercise price (in CAD and USD per share)	$ 4.14
Options granted - Weighted average exercise price (in CAD and USD per share)	2.77
Options exercised - Weighted average exercise price (in CAD and USD per share)	1.70
Options forfeited, canceled or expired - Weighted average exercise price (in CAD and USD per share)	3.31
Options vested (USD per share)	0
Balance - Weighted average exercise price (in CAD and USD per share)	$ 3.76	$ 4.14
Arbutus Plans | Vested Stock Options
Number of optioned common shares
Balance - Number of optioned common shares (in shares)	6,544,348
Options granted (in shares)	0
Options exercised (in shares)	(71,025)
Options forfeited, canceled or expired (in shares)	(100,399)
Options vested (in shares)	3,258,855
Balance - Number of optioned common shares (in shares)	9,631,779	6,544,348
Arbutus Plans | Non-Vested Stock Options
Number of optioned common shares
Balance - Number of optioned common shares (in shares)	4,765,626
Options granted (in shares)	4,808,295
Options exercised (in shares)	0
Options forfeited, canceled or expired (in shares)	(596,847)
Options vested (in shares)	3,258,855
Balance - Number of optioned common shares (in shares)	5,718,219	4,765,626
Weighted average exercise price
Balance - Weighted average exercise price (in CAD and USD per share)	$ 2.71
Options granted - Weighted average exercise price (in CAD and USD per share)	2.09
Options exercised - Weighted average exercise price (in CAD and USD per share)	0
Options forfeited, canceled or expired - Weighted average exercise price (in CAD and USD per share)	2.44
Options vested (USD per share)	2.42
Balance - Weighted average exercise price (in CAD and USD per share)	$ 2.39	$ 2.71

Stock-based compensation - St_2

Stock-based compensation - Stock options outstanding under the Arbutus Plan (Details) - Arbutus Plans $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) $ / shares shares
Stock Option
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of options outstanding (in shares) | shares	15,349,998
Options outstanding, Weighted average exercise price (in USD per share) | $ / shares	$ 3.76
Intrinsic value of stock options | $	$ 380
Weighted-average term remaining	7 years 3 months 18 days
Vested Stock Options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of options outstanding (in shares) | shares	9,631,779
Options outstanding, Weighted average exercise price (in USD per share) | $ / shares	$ 4.07
Intrinsic value of stock options | $	$ 327
Weighted-average term remaining	6 years 7 months 6 days

Stock-based compensation - Valu

Stock-based compensation - Valuation assumptions for stock options under the Arbutus Plan (Details) - Arbutus Plans	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected average option term	5 years 6 months	5 years 7 months 6 days
Expected volatility	97%	93.40%
Expected dividends	0%	0%
Risk-free interest rate	1.77%	0.67%

Stock-based compensation - St_3

Stock-based compensation - Stock option activity for liability-classified options (Details) - Liability classified stock options	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Number of optioned common shares
Balance - Number of optioned common shares (in shares) | shares	20,000
Weighted average exercise price
Balance - Weighted average exercise price (in CAD and USD per share) | $ / shares	$ 12.10

Stock-based compensation - Outs

Stock-based compensation - Outstanding options under the Oncore Option Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Weighted average exercise price
Stock-based compensation expense	$ 7,182	$ 6,424
OnCore Option Plan
Number of optioned common shares
Balance - Number of optioned common shares (in shares)	80,600
Weighted average exercise price
Balance - Weighted average exercise price (in CAD and USD per share)	$ 0.56

Stock-based compensation - St_4

Stock-based compensation - Stock-based compensation expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 7,182	$ 6,424
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2,912	2,777
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 4,270	$ 3,647

Income taxes - Narrative (Detai

Income taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Taxes [Line Items]
Canadian federal and provincial income tax rate	27%	27%
Research and development credits	$ 3,700	$ 3,800
Scientific research and experimental development expenditures available for indefinite carry-forward	83,564	90,255
Deferred tax assets, operating loss carryforwards, subject to expiration	11,700	11,700
Pre-tax domestic losses	28,700	7,700
Pre-tax foreign losses	93,700	80,700
United States
Income Taxes [Line Items]
Net operating losses	203,900	197,800
Investment tax credit carryforward
Income Taxes [Line Items]
Investment tax credits available to reduce Canadian federal income taxes	7,200	7,400
Investment tax credits available to reduce provincial income taxes	2,000	2,100
Research tax credit carryforward
Income Taxes [Line Items]
Scientific research and experimental development expenditures available for indefinite carry-forward	62,200	62,800
Deferred tax assets, operating loss carryforwards, subject to expiration	$ 148,100	$ 177,700

Income taxes - Income tax recon

Income taxes - Income tax reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Computed taxes (benefits) at Canadian federal and provincial tax rates	$ (17,554)	$ (23,864)
Withholding taxes	4,444	0
Other	761	(1,041)
Permanent and other differences	869	4,292
Foreign tax credit applied	(4,444)	0
Federal and Provincial ITCs applied	(324)	(611)
Change in valuation allowance	14,563	15,928
Difference due to income taxed at foreign rates	5,625	4,840
Stock-based compensation	504	456
Income tax expense	$ 4,444	$ 0

Income taxes - Deferred tax ass

Income taxes - Deferred tax assets and liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Components of Deferred Tax Assets [Line Items]
Non-capital losses carryforwards	$ 83,564	$ 90,255
Canadian research and development deductions	16,791	16,968
Book amortization in excess of tax	(461)	(634)
Revenue recognized for tax purposes in excess of revenue recognized for accounting purposes	2,799	4,400
Tax value in excess of accounting value in lease inducements	93	549
Equity accounted for investment	3,375	3,375
U.S. Federal research and development credits	3,633	3,741
Deductible stock options	3,681	3,309
U.S. research and experimental expenditures capitalization	16,471	0
Deferred Tax Asset, Interest Carryforward	1,507	0
Deferred Tax Assets, Tax Deferred Expense, Other	387	0
Deferred revenue	153	1,341
Total deferred tax assets	145,287	130,724
Valuation allowance	(145,287)	(130,724)
Net deferred tax assets (liabilities)	0	0
Qilu Pharmaceutical Co, LTD.
Components of Deferred Tax Assets [Line Items]
Deferred revenue	6,063	0
Federal
Components of Deferred Tax Assets [Line Items]
Investment tax credits	5,278	5,301
Provincial
Components of Deferred Tax Assets [Line Items]
Investment tax credits	$ 1,953	$ 2,119

Related party transactions (Det

Related party transactions (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Oct. 18, 2021
Related Party Transaction [Line Items]
Outstanding preferred shares that converted to common shares (in shares)			22,833,922
Equity method investments	$ 0
Genevant
Related Party Transaction [Line Items]
Equity method investments	$ 0
Ownership interest in equity method investment (as a percent)	16%
Genevant | Equity Method Investee | Administrative and transitional services
Related Party Transaction [Line Items]
Income from related party (less than)	$ 100,000	$ 100,000