Fusion Pharmaceuticals (FUSN) 10-Q 8 Aug 23 2023 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2023	Jul. 28, 2023
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q2
Trading Symbol	FUSN
Entity Registrant Name	Fusion Pharmaceuticals Inc.
Entity Central Index Key	0001805890
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		68,997,564
Entity Tax Identification Number	00-0000000
Entity File Number	001-39344
Entity Address, Address Line One	270 Longwood Rd., S.
Entity Address, City or Town	Hamilton
Entity Address, State or Province	ON
Entity Address, Country	CA
Entity Address, Postal Zip Code	L8P 0A6
City Area Code	289
Local Phone Number	799-0891
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Document Quarterly Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	CA
Title of 12(b) Security	Common shares, no par value per share
Security Exchange Name	NASDAQ

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 32,022		$ 43,861
Accounts receivable	62		61
Short-term investments	166,074		127,013
Prepaid expenses and other current assets	9,283		7,609
Restricted cash	419		454
Total current assets	207,860		178,998
Property and equipment, net	5,709		4,631
Deferred tax assets	5,996		4,806
Restricted cash	849		1,018
Long-term investments	28,423		15,761
Operating lease right-of-use assets	17,632		5,684
Other non-current assets	1,817		8,166
Total assets	268,286		219,064
Current liabilities:
Accounts payable	2,061		2,686
Accrued expenses and other current liabilities	9,343		10,605
Deferred revenue	333		333
Operating lease liabilities	5,357		1,443
Total current liabilities	17,094		15,067
Long-term debt, net of discount	34,492		34,233
Income taxes payable, net of current portion	299		299
Deferred revenue, net of current portion	2,667		2,667
Operating lease liabilities, net of current portion	10,773		4,577
Total liabilities	65,325		56,843
Commitments and contingencies (Note 15)
Shareholders’ equity:
Common stock, $0.001 par value per share (200,000,000 authorized, 36,664,864 and 34,960,672 shares issued and outstanding as of June 30, 2023 and December 31, 2022, respectively)
Additional paid-in capital	534,541		444,552
Accumulated other comprehensive loss	(252)		(469)
Accumulated deficit	(331,328)		(281,862)
Total shareholders' equity	202,961	$ 200,833	162,221
Total liabilities and shareholders’ equity	$ 268,286		$ 219,064

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Common stock, no par value	$ 0	$ 0
Common stock, shares issued	68,990,263	44,805,627
Common stock, shares outstanding	68,990,263	44,805,627

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Statement [Abstract]
Total revenue	$ 34	$ 570	$ 62	$ 1,155
Type of Revenue [Extensible List]	us-gaap:CollaborativeArrangementMember	us-gaap:CollaborativeArrangementMember	us-gaap:CollaborativeArrangementMember	us-gaap:CollaborativeArrangementMember
Operating expenses:
Research and development	$ 18,994	$ 12,076	$ 34,871	$ 24,737
General and administrative	7,753	7,781	16,759	16,230
Total operating expenses	26,747	19,857	51,630	40,967
Loss from operations	(26,713)	(19,287)	(51,568)	(39,812)
Other income (expense):
Interest income	2,495	198	4,416	281
Interest expense	(1,282)	(251)	(2,505)	(251)
Other income (expense), net	80	(414)	(65)	64
Total other income (expense), net	1,293	(467)	1,846	94
Loss before benefit for income taxes	(25,420)	(19,754)	(49,722)	(39,718)
Income tax benefit	245	681	256	736
Net loss	(25,175)	(19,073)	(49,466)	(38,982)
Unrealized (loss) gain on investments	(167)	(482)	217	(945)
Comprehensive loss	$ (25,342)	$ (19,555)	$ (49,249)	$ (39,927)
Net loss per share attributable to common shareholders-basic	$ (0.38)	$ (0.44)	$ (0.82)	$ (0.9)
Net loss per share attributable to common shareholders-diluted	$ (0.38)	$ (0.44)	$ (0.82)	$ (0.9)
Weighted-average common shares outstanding-basic	66,277,279	43,357,240	60,061,166	43,264,175
Weighted-average common shares outstanding-diluted	66,277,279	43,357,240	60,061,166	43,264,175

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Private Placement [Member]	At-The-Market Offering [Member]	Common Shares [Member]	Common Shares [Member] Private Placement [Member]	Common Shares [Member] At-The-Market Offering [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Private Placement [Member]	Additional Paid-in Capital [Member] At-The-Market Offering [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning Balance at Dec. 31, 2021	$ 231,456						$ 425,821			$ (194,250)	$ (115)
Beginning Balance (in shares) at Dec. 31, 2021				43,073,727
Issuance of common shares, net of issuance costs			$ 1,627						$ 1,627
Issuance of common shares, net of issuance costs (in shares)						222,726
Issuance of common shares upon exercise of stock options	82						82
Issuance of common shares upon exercise of stock options (in shares)				34,685
Share-based compensation expense	2,633						2,633
Unrealized (loss) gain on investments	(463)										(463)
Net loss	(19,909)									(19,909)
Ending Balance at Mar. 31, 2022	215,426						430,163			(214,159)	(578)
Ending Balance (in shares) at Mar. 31, 2022				43,331,138
Beginning Balance at Dec. 31, 2021	231,456						425,821			(194,250)	(115)
Beginning Balance (in shares) at Dec. 31, 2021				43,073,727
Unrealized (loss) gain on investments	(945)
Net loss	(38,982)
Ending Balance at Jun. 30, 2022	198,907						433,199			(233,232)	(1,060)
Ending Balance (in shares) at Jun. 30, 2022				43,384,510
Beginning Balance at Mar. 31, 2022	215,426						430,163			(214,159)	(578)
Beginning Balance (in shares) at Mar. 31, 2022				43,331,138
Issuance of common share warrants	147						147
Issuance of common shares, net of issuance costs			74						74
Issuance of common shares, net of issuance costs (in shares)						10,000
Issuance of common shares upon exercise of stock options	79						79
Issuance of common shares upon exercise of stock options (in shares)				43,372
Share-based compensation expense	2,736						2,736
Unrealized (loss) gain on investments	(482)										(482)
Net loss	(19,073)									(19,073)
Ending Balance at Jun. 30, 2022	198,907						433,199			(233,232)	(1,060)
Ending Balance (in shares) at Jun. 30, 2022				43,384,510
Beginning Balance at Dec. 31, 2022	162,221			$ 444,552						(281,862)	(469)
Beginning Balance (in shares) at Dec. 31, 2022				44,805,627
Issuance of common shares, net of issuance costs		$ 56,003	3,367					$ 56,003	3,367
Issuance of common shares, net of issuance costs (in shares)					17,648,596	747,336
Share-based compensation expense	3,149						3,149
Unrealized (loss) gain on investments	384										384
Net loss	(24,291)									(24,291)
Ending Balance at Mar. 31, 2023	200,833						507,071			(306,153)	(85)
Ending Balance (in shares) at Mar. 31, 2023				63,201,559
Beginning Balance at Dec. 31, 2022	$ 162,221			$ 444,552						(281,862)	(469)
Beginning Balance (in shares) at Dec. 31, 2022				44,805,627
Issuance of common shares upon exercise of stock options (in shares)	3,221
Unrealized (loss) gain on investments	$ 217
Net loss	(49,466)
Ending Balance at Jun. 30, 2023	202,961						534,541			(331,328)	(252)
Ending Balance (in shares) at Jun. 30, 2023				68,990,263
Beginning Balance at Mar. 31, 2023	200,833						507,071			(306,153)	(85)
Beginning Balance (in shares) at Mar. 31, 2023				63,201,559
Issuance of common shares, net of issuance costs		$ 19,971	$ 4,442					$ 19,971	$ 4,442
Issuance of common shares, net of issuance costs (in shares)					4,784,689	1,000,794
Issuance of common shares upon exercise of stock options	11						11
Issuance of common shares upon exercise of stock options (in shares)				3,221
Share-based compensation expense	3,046						3,046
Unrealized (loss) gain on investments	(167)										(167)
Net loss	(25,175)									(25,175)
Ending Balance at Jun. 30, 2023	$ 202,961						$ 534,541			$ (331,328)	$ (252)
Ending Balance (in shares) at Jun. 30, 2023				68,990,263

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities:
Net loss	$ (49,466)	$ (38,982)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	6,195	5,369
Depreciation and amortization expense	610	419
Non-cash lease expense	999	565
Non-cash interest expense	259	38
(Accretion) amortization of (discounts) premiums on investments, net	(2,592)	277
Deferred tax benefit	(1,190)	(593)
Other	212	1
Changes in operating assets and liabilities:
Accounts receivable	(1)	180
Prepaid expenses and other current assets	(1,675)	1,895
Operating lease right-of-use assets		182
Other non-current assets	3,820	66
Accounts payable	(544)	(637)
Accrued expenses and other current liabilities	(1,127)	324
Deferred revenue		(831)
Operating lease liabilities	(519)	(560)
Net cash used in operating activities	(45,019)	(32,287)
Cash flows from investing activities:
Purchases of investments	(132,504)	(49,551)
Maturities of investments	83,590	79,293
Purchases of property and equipment	(1,933)	(970)
Net cash (used in) provided by investing activities	(50,847)	28,772
Cash flows from financing activities:
Proceeds from issuance of debt		9,835
Proceeds from issuance of common shares from private placement	80,005
Proceeds from issuance of common shares from at-the-market offering, net of issuance costs	7,809	1,701
Payment of offering costs	(4,002)
Proceeds from issuance of common shares upon exercise of stock options	11	161
Net cash provided by financing activities	83,823	11,697
Net (decrease) increase in cash, cash equivalents and restricted cash	(12,043)	8,182
Cash, cash equivalents and restricted cash at beginning of period	45,333	54,789
Cash, cash equivalents and restricted cash at end of period	33,290	62,971
Supplemental disclosure of cash flow information:
Cash paid for income taxes	816	276
Cash paid for interest	2,246	213
Right-of-use assets obtained in exchange for new operating lease liabilities	12,947	339
Supplemental disclosure of non-cash investing and financing activities:
Purchases of property and equipment included in accounts payable and accrued expenses	363	166
Common share issuance costs included in accounts payable and accrued expenses	$ 29
Issuance of common share warrants under debt facility		$ 147

Nature of the Business and Basi

Nature of the Business and Basis of Presentation	6 Months Ended
	Jun. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business and Basis of Presentation	1. Nature of the Business and Basis of Presentation Fusion Pharmaceuticals Inc., together with its consolidated subsidiary (“Fusion” or the “Company”), is a clinical-stage oncology company focused on developing next-generation radiopharmaceuticals as precision medicines. The Company was formed and subsequently incorporated as Fusion Pharmaceuticals Inc. in December 2014 under the Canada Business Corporations Act. The Company was founded to advance certain intellectual property relating to radiopharmaceuticals that had been developed by the Centre for Probe Development and Commercialization, a radiopharmaceutical research and good manufacturing practice production center. The Company is headquartered in Hamilton, Ontario. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, successful discovery and development of its product candidates, development by competitors of new technological innovations, dependence on key personnel, the ability to attract and retain qualified employees, protection of proprietary technology, compliance with governmental regulations, the impact of the COVID-19 pandemic and overall market conditions, the ability to secure additional capital to fund operations and commercial success of its product candidates. Product candidates currently under development will require extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel, and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s drug development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. The accompanying condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of the Company and its wholly-owned subsidiary, Fusion Pharmaceuticals US Inc. All intercompany accounts and transactions have been eliminated in consolidation. Basis of Presentation The accompanying condensed consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. Since inception, the Company has funded its operations primarily with proceeds from sales of its convertible preferred shares, including borrowings under a convertible promissory note, which converted into convertible preferred shares, proceeds from sales of its former Irish subsidiary’s preferred exchangeable shares, proceeds from its initial public offering completed in June 2020, proceeds from its “at-the-market” equity offering program (see Note 9), proceeds from its loan and security agreement with Oxford Finance LLC executed in April 2022 (see Note 8), and proceeds from private placement financings completed in February 2023 and May 2023 (see Note 9). The Company has incurred recurring losses since its inception, including net losses of $ 25.2 million and $ 49.5 million for the three and six months ended June 30, 2023 , respectively, and net losses of $ 19.1 million and $ 39.0 million for the three and six months ended June 30, 2022, respectively. In addition, as of June 30, 2023, the Company had an accumulated deficit of $ 331.3 million. The Company expects to continue to generate operating losses for the foreseeable future. As of the issuance date of these condensed consolidated financial statements, the Company expects that its cash, cash equivalents and investments will be sufficient to fund its operating expenses and capital expenditure requirements for at least the next 12 months. The future viability of the Company is dependent on its ability to raise additional capital to finance its operations. Impacts of COVID-19 and Market Conditions on Our Business The Company believes its financial results for the three and six months ended June 30, 2023 and year ended December 31, 2022 were not significantly impacted by the COVID-19 pandemic. The Company believes its hybrid and remote working arrangements have had limited impact on its ability to maintain internal operations during the three and six months ended June 30, 2023 and year ended December 31, 2022 . Further, disruption of global financial markets and a recession or market correction, including as a result of the COVID-19 pandemic, the ongoing military conflict between Russia and Ukraine and the related sanctions imposed against Russia, and other global macroeconomic factors such as inflation and the recent banking industry volatility, could reduce the Company’s ability to access capital, which could, in the future, negatively affect its business and the value of its common shares.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The preparation of the Company’s condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, the accrual of research and development expenses, valuations of share-based awards, valuation allowance of deferred tax assets, and revenue recognition. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates when there are changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results may differ from those estimates or assumptions. Unaudited Interim Financial Information The accompanying condensed consolidated balance sheet as of June 30, 2023, the condensed consolidated statement of operations and comprehensive loss, and the condensed consolidated statement of shareholders’ equity, and the condensed consolidated statement of cash flows for the three and six months ended June 30, 2023 and 2022 are unaudited. The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of June 30, 2023 and the results of its operations and its cash flows for the three and six months ended June 30, 2023 and 2022. The results for the three and six months ended June 30, 2023 are not necessarily indicative of results to be expected for the year ending December 31, 2023, any other interim periods, or any future year or period. The accompanying balance sheet as of December 31, 2022 has been derived from the Company’s audited financial statements for the year ended December 31, 2022. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to rules and regulations. However, the Company believes that the disclosures are adequate to make the information presented not misleading. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited annual consolidated financial statements as of December 31, 2022 , and notes thereto, which are included in the Company’s Annual Report on Form 10-K that was filed with the SEC on March 16, 2023. Foreign Currency and Currency Translation The reporting currency of the Company is the U.S. dollar. The functional currency of the Company’s operating company in Canada and operating company in the U.S. is also the U.S. dollar. As a result, the Company records no cumulative translation adjustments related to translation of unrealized foreign exchange gains or losses. For the remeasurement of local currencies to the U.S. dollar functional currency of the Canadian entity, assets and liabilities are translated into U.S. dollars at the exchange rate in effect on the balance sheet date, and income items and expenses are translated into U.S. dollars at the average exchange rate in effect during the period. Resulting transaction gains (losses) are included in other income (expense), net in the condensed consolidated statements of operations and comprehensive loss, as incurred. Adjustments that arise from exchange rate changes on transactions denominated in a currency other than the local currency are included in other income (expense), net in the condensed consolidated statements of operations and comprehensive loss, as incurred. During the three and six months ended June 30, 2023 , the Company recorded $ 0.1 million and $( 0.3 ) million, respectively, of foreign currency gains (losses) in the condensed consolidated statements of operations and comprehensive loss. During the three and six months ended June 30, 2022 , the Company recorded $( 0.6 ) million and $( 0.3 ) million, respectively, of foreign currency (losses) in the condensed consolidated statements of operations and comprehensive loss. Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents consist of standard checking accounts, money market accounts, and all highly liquid investments with an original maturity of three months or less at the date of purchase. As of June 30, 2023 and December 31, 2022 , the Company was required to maintain a separate cash balance of $ 0.2 million to collateralize corporate credit cards with a bank, which was classified as restricted cash, current, on its condensed consolidated balance sheets. The Company also maintained a $ 0.1 million guaranteed investment certificate to fulfill certain contractual obligations which was classified as restricted cash, current, as of June 30, 2023 and December 31, 2022. In connection with the Company’s lease agreement entered into in October 2019 (see Note 14), the Company maintained a letter of credit of $ 1.5 million for the benefit of the landlord, which was reduced to $ 1.0 million during the six months ended June 30, 2023. As of June 30, 2023 , $ 0.2 million and $ 0.8 million of the underlying cash balance collateralizing this letter of credit was classified as restricted cash, current and non-current, respectively, on the Company’s condensed consolidated balance sheets based on the release date of the restrictions of this cash. As of December 31, 2022 , $ 0.2 million and $ 1.0 million of the underlying cash balance collateralizing this letter of credit was classified as restricted cash, current and non-current, respectively, on the Company’s condensed consolidated balance sheets based on the release date of the restrictions of this cash. As of June 30, 2023 and December 31, 2022, the cash, cash equivalents and restricted cash of $ 33.3 million and $ 45.3 million, respectively, presented in the condensed consolidated statements of cash flows included cash and cash equivalents of $ 32.0 million and $ 43.9 million, respectively, and restricted cash of $ 1.3 million and $ 1.5 million, respectively. Investments The Company adopted ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”) effective January 1, 2023, and the adoption did not have a material impact on its condensed consolidated financial statements. The Company determines the appropriate classification of its investments in debt securities at the time of purchase and re-evaluates such determination at each balance sheet date. The Company classifies its investments as current or non-current based on each instrument’s underlying maturity date. Investments with original maturities of greater than three months and remaining maturities less than twelve months are classified as current and are included in short-term investments in the condensed consolidated balance sheets. Investments with remaining maturities greater than one year from the balance sheet date are classified as non-current and are included in long-term investments in the condensed consolidated balance sheets. The Company’s investments are classified as available-for-sale, are reported at fair value and consist of U.S. and Canadian government agency debt securities, corporate bonds, and commercial paper. Unrealized gains and losses are included in other comprehensive (loss) income as a component of shareholders’ equity until realized. Amortization and accretion of premiums and discounts are recorded in interest income. Realized gains and losses on debt securities are included in other (expense) income, net. The Company reviews its portfolio of available-for-sale debt securities, using both quantitative and qualitative factors, to determine if declines in fair value below cost have resulted from a credit-related loss or other factors. If the decline in fair value is due to credit-related factors, a loss is recognized in net loss, and if the decline in fair value is not due to credit-related factors, the loss is recorded in other comprehensive loss. No credit losses were recorded during the periods presented. Deferred Offering Costs The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of an equity financing, these costs are recorded as a reduction of the proceeds from the offering in shareholders’ equity as a reduction of additional paid-in capital generated as a result of the offering. Should an in-process equity financing be abandoned, the deferred offering costs would be expensed immediately as a charge to operating expenses in the condensed consolidated statements of operations and comprehensive loss. The Company recorded $ 0.1 million and $ 0.2 million of deferred offering costs as of June 30, 2023 and December 31, 2022 , respectively, in other non-current assets. Collaborative Arrangements The Company considers the nature and contractual terms of arrangements and assesses whether an arrangement involves a joint operating activity pursuant to which the Company is an active participant and is exposed to significant risks and rewards dependent on the commercial success of the activity. If the Company is an active participant and is exposed to significant risks and rewards dependent on the commercial success of the activity, the Company accounts for such arrangement as a collaborative arrangement under ASC 808, Collaborative Arrangements . ASC 808 describes arrangements within its scope and considerations surrounding presentation and disclosure, with recognition matters subjected to other authoritative guidance, in certain cases by analogy. For arrangements determined to be within the scope of ASC 808 where a collaborative partner is not a customer for certain research and development activities, the Company accounts for payments received for the reimbursement of research and development costs as a contra-expense in the period such expenses are incurred. This reflects the joint risk sharing nature of these activities within a collaborative arrangement. The Company classifies payments owed or receivables recorded as other current liabilities or prepaid expenses and other current assets, respectively, in the Company’s consolidated balance sheets. If payments from the collaborative partner to the Company represent consideration from a customer in exchange for distinct goods and services provided, then the Company accounts for those payments within the scope of ASC 606, Revenue from Contracts with Customers (“ASC 606”). Please refer to Note 3, “Collaboration Agreement” for additional details regarding the Company’s Strategic Collaboration Agreement with AstraZeneca UK Limited (“AstraZeneca”) (the “AstraZeneca Agreement”). Revenue from Contracts with Customers In accordance with ASC 606, the Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, it performs the following five steps: (i) identify the 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 within the contract and (v) recognize revenue when (or as) the Company satisfies a performance obligation. The Company only applies the five-step model to contracts when it determines that it is probable it will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within the contract to determine whether each promised good or service is a performance obligation. The promised goods or services in the Company’s arrangements typically consist of a license to the Company’s intellectual property and/or research and development services. The Company may provide customers with options to additional items in such arrangements, which are accounted for separately when the customer elects to exercise such options, unless the option provides a material right to the customer. Performance obligations are promises in a contract to transfer a distinct good or service to the customer that (i) the customer can benefit from on its own or together with other readily available resources, and (ii) is separately identifiable from other promises in the contract. Goods or services that are not individually distinct performance obligations are combined with other promised goods or services until such combined group of promises meet the requirements of a performance obligation. The Company determines transaction price based on the amount of consideration the Company expects to receive for transferring the promised goods or services in the contract. Consideration may be fixed, variable, or a combination of both. At contract inception for arrangements that include variable consideration, the Company estimates the probability and extent of consideration it expects to receive under the contract utilizing either the most likely amount method or expected amount method, whichever best estimates the amount expected to be received. The Company then considers any constraints on the variable consideration and includes in the transaction price variable consideration to the extent it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. The Company then allocates the transaction price to each performance obligation based on the relative standalone selling price and recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) control is transferred to the customer and the performance obligation is satisfied. For performance obligations which consist of licenses and other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The Company records amounts as accounts receivable when the right to consideration is deemed unconditional. Amounts received, or that are unconditionally due, from a customer prior to transferring goods or services to the customer under the terms of a contract are recognized as deferred revenue. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as the current portion of deferred revenue. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion. The Company’s revenue generating arrangements typically include upfront license fees, milestone payments and/or royalties. If a license is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenue from nonrefundable, up-front fees allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from non-refundable, up-front fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. At the inception of an agreement that includes research and development milestone payments, the Company evaluates each milestone to determine when and how much of the milestone to include in the transaction price. The Company first estimates the amount of the milestone payment that the Company could receive using either the expected value or the most likely amount approach. The Company primarily uses the most likely amount approach as this approach is generally most predictive for milestone payments with a binary outcome. Then, the Company considers whether any portion of the estimated amount is subject to the variable consideration constraint (that is, whether it is probable that a significant reversal of cumulative revenue would not occur upon resolution of the uncertainty). The Company updates the estimate of variable consideration included in the transaction price at each reporting date which includes updating the assessment of the likely amount of consideration and the application of the constraint to reflect current facts and circumstances. For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company will recognize revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). For the three and six months ended June 30, 2023 , the Company recorded less than $ 0.1 million and $ 0.1 million, respectively, of revenue under collaboration agreements. For the three and six months ended June 30, 2022 , the Company recorded $ 0.6 million and $ 1.2 million, respectively, of revenue under collaboration agreements. Please refer to Note 3, “Collaboration Agreement” for additional details regarding revenue recognition under the AstraZeneca Agreement. Business Combinations In determining whether an acquisition should be accounted for as a business combination or asset acquisition, the Company first determines whether substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets. If this is the case, the single identifiable asset or the group of similar assets is not deemed to be a business, and is instead deemed to be an asset. If this is not the case, the Company then further evaluates whether the single identifiable asset or group of similar identifiable assets and activities includes, at a minimum, an input and a substantive process that together significantly contribute to the ability to create outputs. If so, the Company concludes that the single identifiable asset or group of similar identifiable assets and activities is a business. The Company accounts for business combinations using the acquisition method of accounting. Application of this method of accounting requires that (i) identifiable assets acquired (including identifiable intangible assets) and liabilities assumed generally be measured and recognized at fair value as of the acquisition date and (ii) the excess of the purchase price over the net fair value of identifiable assets acquired and liabilities assumed be recognized as goodwill, which is not amortized for accounting purposes but is subject to testing for impairment at least annually. Acquired in-process research and development (“IPR&D”) is recognized at fair value and initially characterized as an indefinite-lived intangible asset, irrespective of whether the acquired IPR&D has an alternative future use. Transaction costs related to business combinations are expensed as incurred. Determining the fair value of assets acquired and liabilities assumed in a business combination requires management to use significant judgment and estimates, especially with respect to intangible assets. During the measurement period, which extends no later than one year from the acquisition date, the Company may record certain adjustments to the carrying value of the assets acquired and liabilities assumed with the corresponding offset to goodwill. After the measurement period, all adjustments are recorded in the consolidated statements of operations as operating expenses or income. To date, the Company has not recorded any acquisitions as a business combination. Asset Acquisitions The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the assets, which includes transaction costs. Goodwill is not recognized in asset acquisitions. In an asset acquisition, the cost allocated to acquire IPR&D with no alternative future use is charged to expense at the acquisition date. Contingent consideration in asset acquisitions payable in the form of cash is recognized when payment becomes probable and reasonably estimable, unless the contingent consideration meets the definition of a derivative, in which case the amount becomes part of the asset acquisition cost when acquired. Contingent consideration payable in the form of a fixed number of the Company’s own shares is measured at fair value as of the acquisition date and recognized when the issuance of the shares becomes probable. Upon recognition of the contingent consideration payment, the amount is included in the cost of the acquired asset or group of assets, or, if related to IPR&D with no alternative future use, charged to expense. Fair Value Measurements Certain assets and liabilities of the Company are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The Company’s cash equivalents and investments are carried at fair value, determined according to the fair value hierarchy described above (see Note 4). The carrying values of the Company’s amounts due for Canadian harmonized sales tax, accounts payable and accrued expenses approximate their fair values due to the short-term nature of these liabilities. Leases The Company accounts for leases in accordance with ASC 842, Leases . At contract inception, the Company determines if an arrangement is or contains a lease. A lease conveys the right to control the use of an identified asset for a period of time in exchange for consideration. If determined to be or contain a lease, the lease is assessed for classification as either an operating or finance lease at the lease commencement date, defined as the date on which the leased asset is made available for use by the Company, based on the economic characteristics of the lease. For each lease with a term greater than twelve months, the Company records a right-of-use asset and lease liability. A right-of-use asset represents the economic benefit conveyed to the Company by the right to use the underlying asset over the lease term. A lease liability represents the obligation to make lease payments arising from the lease. The Company records amortization of operating right-of-use assets and accretion of lease liabilities as a single lease cost on a straight-line basis over the lease term. The Company elected the practical expedient to not separate lease and non-lease components and therefore measures each lease payment as the total of the fixed lease and associated non-lease components. Lease liabilities are measured at the lease commencement date and calculated as the present value of the future lease payments in the contract using the rate implicit in the contract, when available. If an implicit rate is not readily determinable, the Company uses its incremental borrowing rate measured as the rate at which the Company could borrow, on a fully collateralized basis, a commensurate loan in the same currency over a period consistent with the lease term at the commencement date. Right-of-use assets are measured as the lease liability plus initial direct costs and prepaid lease payments, less lease incentives granted by the lessor. The lease term is measured as the noncancelable period in the contract, adjusted for any options to extend or terminate when it is reasonably certain the Company will extend the lease term via such options based on an assessment of economic factors present as of the lease commencement date. The Company elected the practical expedient to not recognize leases with a lease term of twelve months or less. The Company assesses its right-of-use assets for impairment consistent with the assessment performed for long-lived assets used in operations. If an impairment is recognized on operating lease right-of-use assets, the lease liability continues to be recognized using the same effective interest method as before the impairment and the operating lease right-of-use asset is amortized over the remaining term of the lease on a straight-line basis. The Company’s operating leases are presented in the condensed consolidated balance sheet as operating lease right-of-use assets, classified as noncurrent assets, and operating lease liabilities, classified as current and noncurrent liabilities based on the discounted lease payments to be made within the proceeding twelve months. Variable costs associated with a lease, such as maintenance and utilities, are not included in the measurement of the lease liabilities and right-of-use assets but rather are expensed when the events determining the amount of variable consideration to be paid have occurred. Research, Development and Manufacturing Contract Costs and Accruals The Company has entered into various research, development and manufacturing contracts with research institutions and other companies. These agreements are generally cancelable, and related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research, development and manufacturing costs. When billing terms under these contracts do not coincide with the timing of when the work is performed, the Company is required to make estimates of outstanding obligations to those third parties as of period end. Any accrual estimates are based on a number of factors, including the Company’s knowledge of the progress towards completion of the research, development and manufacturing activities, invoicing to date under the contracts, communication from the research institutions and other companies of any actual costs incurred during the period that have not yet been invoiced and the costs included in the contracts. Significant judgments and estimates may be made in determining the accrued balances at the end of any reporting period. Actual results could differ from the estimates made by the Company. The historical accrual estimates made by the Company have not been materially different from the actual costs. Comprehensive Loss Comprehensive loss includes net loss as well as other changes in shareholders’ equity that result from transactions and economic events other than those with shareholders. For the three and six months ended June 30, 2023 and 2022 , unrealized gains and losses on investments are included in other comprehensive (loss) income as a component of shareholders’ equity until realized. Net Loss per Share Basic net income (loss) per share attributable to common shareholders is computed by dividing the net income (loss) attributable to common shareholders by the weighted-average number of common shares outstanding for the period. Diluted net income (loss) attributable to common shareholders is computed by adjusting net income (loss) attributable to common shareholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net income (loss) per share attributable to common shareholders is computed by dividing the diluted net income (loss) attributable to common shareholders by the weighted-average number of common shares outstanding for the period, including potential dilutive common shares. For purposes of this calculation, outstanding stock options, restricted stock units and warrants are considered potential dilutive common shares. Recently Adopted Accounting Pronouncements The Company qualifies as “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 and has elected to “opt in” to the extended transition related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different application dates for public and nonpublic companies, the Company will adopt the new or revised standard at the time nonpublic companies adopt the new or revised standard and will do so until such time that the Company either (i) irrevocably elects to “opt out” of such extended transition period or (ii) no longer qualifies as an emerging growth company. The Company may choose to early adopt any new or revised accounting standards whenever such early adoption is permitted for private companies. In June 2016, the FASB issued ASU 2016-13 which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available-for-sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. These changes will result in earlier recognition of credit losses. In November 2018, the FASB issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments—Credit Losses , which narrowed the scope and changed the effective date for non-public entities for ASU 2016-13. The FASB subsequently issued supplemental guidance within ASU No. 2019-05, Financial Instruments—Credit Losses (Topic 326): Targeted Transition Relief (“ASU 2019-05”). ASU 2019-05 provides an option to irrevocably elect the fair value option for certain financial assets previously measured at amortized cost basis. This guidance is effective for the Company for annual periods beginning after December 15, 2022, including interim periods within that fiscal year. The Company adopted ASU 2016-13 effective January 1, 2023, and the adoption did not have a material impact on its condensed consolidated financial statements.

Collaboration Agreement

Collaboration Agreement	6 Months Ended
	Jun. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration Agreement	3. Collaboration Agreement Strategic Collaboration Agreement with AstraZeneca UK Limited In October 2020, the Company and AstraZeneca entered into the AstraZeneca Agreement pursuant to which the Company and AstraZeneca will work to jointly discover, develop and commercialize next-generation alpha-emitting radiopharmaceuticals and combination therapies for the treatment of cancer globally by leveraging the Company’s Targeted Alpha Therapies (“TATs”) platform and expertise in radiopharmaceuticals with AstraZeneca’s leading portfolio of antibodies and cancer therapeutics, including DNA damage response inhibitors (“DDRis”). Each party retains full ownership over its existing assets. The AstraZeneca Agreement consists of two distinct collaboration programs: novel TATs and combination therapies. Under the AstraZeneca Agreement, the parties may develop up to three novel TATs (the “Novel TATs Collaboration”). The parties will also evaluate up to five potential combination strategies involving the Company’s existing assets, including the Company’s lead candidate FPI-1434, in combination with certain of AstraZeneca’s existing therapeutics for the treatment of various cancers (the “Combination Therapies Collaboration”). The AstraZeneca Agreement expires on a TAT-by-TAT and combination-by-combination basis upon the later of the expiration of development and exclusivity obligations relating to such TAT or combination or, if such TAT or combination is commercialized as a product under the AstraZeneca Agreement, the expiration of the commercial life of such product. The Company and AstraZeneca can each terminate the AstraZeneca Agreement for the other party’s uncured material breach following the applicable notice period. Each of the Company and AstraZeneca may also terminate the AstraZeneca Agreement with respect to any TAT or combination product if such party determines that the continued development of such TAT or combination product is not commercially viable, or for a material safety issue with respect to such TAT or combination product. Novel TATs Collaboration As part of the Novel TATs Collaboration, the parties may develop up to three novel TATs. The Company and AstraZeneca will share development costs equally (with each party responsible for the cost of its own supply in connection with such development). Either party has the right to opt out of the co-development and co-commercialization arrangement at pre-determined timepoints and obtain exclusive rights to a novel TAT in exchange for milestone payments to the other party of up to $ 145.0 million per novel TAT and a low or high single-digit royalties on future sales (depending on the opt out time point). If neither party opts out, and unless otherwise agreed by the parties, AstraZeneca will lead worldwide commercialization activities for the novel TATs, subject to the Company’s option to co-promote the TATs in the U.S. All profits and losses resulting from such commercialization activities will be shared equally. In January 2022, the Company announced the nomination of the first novel TAT candidate under the Novel TATs Collaboration, which the Company refers to as FPI-2068. FPI-2068 is a TAT designed to deliver 225 Ac to various solid tumors that express epidermal growth factor receptor (“EGFR”) and mesenchymal epithelial transition factor (“cMET”). In April 2023, the Company announced the clearance of investigational new drug applications (“INDs”) for FPI-2068 and its corresponding imaging analogue, FPI-2107, by the FDA. The Novel TATs Collaboration is within the scope of ASC 808 as the Company and AstraZeneca are both active participants in the research and development activities and are exposed to significant risks and rewards that are dependent on commercial success of the activities of the arrangement. The research and development activities are a unit of account under the scope of ASC 808 and are not promises to a customer under the scope of ASC 606. The Company records its portion of the research and development expenses as the related expenses are incurred. All payments received or amounts due from AstraZeneca for reimbursement of shared costs are accounted for as an offset to research and development expense. For the three and six months ended June 30, 2023 , the Company incurred $ 0.9 million and $ 2.7 million, respectively, in research and development expenses relating to the Novel TATs Collaboration which was offset by $ 0.5 million and $ 1.1 million, respectively, in amounts due from AstraZeneca for reimbursement of shared costs. For the three and six months ended June 30, 2022 , the Company incurred $ 2.6 million and $ 3.3 million, respectively, in research and development expenses relating to the Novel TATs Collaboration which was offset by $ 1.2 million and $ 1.6 million, respectively, in amounts due from AstraZeneca for reimbursement of shared costs. As of June 30, 2023 and December 31, 2022 , the Company recorded $ 1.1 million and $ 0.4 million, respectively, due from AstraZeneca for reimbursement of shared costs in prepaid expenses and other current assets. Combination Therapies Collaboration As part of the Combination Therapies Collaboration, the parties will evaluate up to five potential combination strategies involving the Company’s existing assets, including the Company’s FPI-1434 product candidate, in combination with certain of AstraZeneca’s existing therapeutics for the treatment of various cancers. The Company received an upfront payment of $ 5.0 million from AstraZeneca in December 2020 associated with the Combination Therapies Collaboration. AstraZeneca will fully fund all research and development activities for the combination strategies, until such point as the Company may opt-in to the clinical development activities. The Company also has the right to opt-out of clinical development activities relating to these combination therapies. In such instance, the Company will be responsible for repaying its share of the development costs via a royalty on the additional combination sales only if its drug is approved on the basis of clinical development solely conducted by AstraZeneca, in which case the royalty payments shall also include a variable risk premium based on the number of the Company’s product candidates to have received regulatory approval at that time. Each party will have the sole right, on a country-by-country basis, to commercialize its respective contributed compound as a component of any combination therapy for which such party’s contributed compound may be commercialized under a separate marketing authorization from the other party’s contributed compound to such combination therapy. The parties will negotiate in good faith on a combination therapy-by-combination therapy basis the terms and conditions to co-commercialize any combination therapy that is to be commercialized under a single marketing authorization. During the period of time commencing with the inclusion of an available molecular target in the selection pool for development as a combination therapy and ending upon the end of the nomination period or earlier removal of such combination target from such pool, the Company will not undertake any preclinical or clinical studies combining the Company’s TAT platform with any compound modulating the activity of such combination target. Following selection of a target under the AstraZeneca Agreement and payment of an exclusivity fee by AstraZeneca, and provided that AstraZeneca enrolls its first patient in a clinical trial as further defined in the AstraZeneca Agreement within a pre-defined period of time of such selection, the Company will not undertake any preclinical or clinical studies combining the Company’s TAT platform with compounds modulating the same combination target for the duration of the evaluation period for such combination target, as further defined in the AstraZeneca Agreement. Within a certain time period following initiation of the evaluation period with respect to a combination target, AstraZeneca has the exclusive right to undertake, alone or in collaboration with the Company, all further clinical or preclinical combination studies with respect to a combination target by paying certain exclusivity fees. The Company is eligible to receive future payments of up to $ 40.0 million, including those for the achievement of certain clinical milestones and exclusivity fees. The Company determined the research and development activities associated with the Combination Therapies Collaboration are a key component of its central operations and AstraZeneca has contracted with the Company to obtain goods and services which are an output of the Company’s ordinary activities in exchange for consideration. Further, the Company does not share the risks and rewards of the underlying research activities making AstraZeneca a customer for the Combination Therapies Collaboration which falls within the scope of ASC 606. To determine the appropriate amount of revenue to be recognized under ASC 606, the Company performed the following steps: (i) identify the promised goods or services in the contract, (ii) determine whether the promised goods or services are performance obligations, including whether they are distinct in the context of the contract, (iii) measure the transaction price, including the constraint on variable consideration, (iv) allocate the transaction price to the performance obligations and (v) recognize revenue when (or as) the Company satisfies each performance obligation. Under ASC 606 the Company accounts for (i) the license it conveyed to AstraZeneca with respect to certain intellectual property and (ii) the obligations to perform research and development services as part of the Combination Therapies Collaboration as a single performance obligation under the AstraZeneca Agreement. The Company concluded AstraZeneca’s right to purchase exclusive options to obtain certain development, manufacturing and commercialization rights represent customer options that are not performance obligations as they do not contain any discounts or other rights that would be considered a material right in the arrangement. Such options will be accounted for upon AstraZeneca’s election. The Company determined the transaction price under ASC 606 at the inception of the AstraZeneca Agreement to be the $ 5.0 million upfront payment. The cost reimbursement payments for all costs incurred by the Company under the Combination Therapies Collaboration represent variable consideration that is not constrained. Additionally, the clinical milestone payments represent variable consideration that is constrained. In making this assessment, the Company considered several factors, including the fact that achievement of the milestones are outside its control and contingent upon the future success of clinical trials and AstraZeneca’s actions. The payments related to the achievement of certain clinical milestones do not relate to separate, distinct performance obligations. Under ASC 606, the Company recognizes revenue using the cost-to-cost method, which it believes best depicts the transfer of control to the customer. Under the cost-to-cost method, the extent of progress towards completion is measured based on the ratio of actual costs incurred to the total estimated costs expected upon satisfying the identified performance obligation. Under this method, revenue is recorded as a percentage of the estimated transaction price based on the extent of progress towards completion. Under ASC 606, the estimated transaction price includes variable consideration that is not constrained. The Company does not include variable consideration to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will occur when any uncertainty associated with the variable consideration is resolved. The estimate of the Company’s measurement of progress and estimate of variable consideration to be included in the transaction price will be updated at each reporting date as a change in estimate. For the clinical milestone payments, the Company utilizes the most likely amount method to determine the amounts recognized and timing of recognition. Once the constraint is removed, the clinical milestone payments will be accounted for with the research and development services for the purposes of revenue recognition which will occur over time as the services are provided. Upon the achievement of any milestone for specified clinical development events, the Company will utilize the same cost-to-cost model with a cumulative catch-up recognized in the period in which any such event occurs. The Company will re-evaluate the transaction price at the end of each reporting period and as uncertain events are resolved, or other changes in circumstances occur, adjust its estimate of the transaction price if necessary. The Company initially recorded the $5.0 million upfront fee as a contract liability for deferred revenue in its consolidated balance sheet. The following table presents changes in the Company’s accounts receivable and contract liabilities for the six months ended June 30, 2023 (in thousands): Balance as of Balance as of December 31, 2022 Additions Deductions June 30, 2023 Accounts receivable $ 61 $ 62 $ ( 61 ) $ 62 Contract liabilities: Deferred revenue $ 3,000 $ — $ — $ 3,000 During the three and six months ended June 30, 2023 and 2022, the Company recognized the following revenue (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Revenue recognized in the period from: Amounts included in deferred revenue at the beginning of the period $ — $ 393 $ — $ 831 The current portion of deferred revenue and deferred revenue, net of current portion, are $ 0.3 million and $ 2.7 million as of June 30, 2023 , respectively, which reflects the Company’s estimate of the revenue it expects to recognize within the next 12 months and beyond 12 months, respectively. The Company expects to recognize the revenue associated with the AstraZeneca Agreement in subsequent periods through the year ending December 31, 2026.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements The following tables present information about the Company’s financial assets and liabilities that are measured at fair value on a recurring basis and indicates the level of the fair value hierarchy used to determine such fair values (in thousands): Fair Value Measurements as of Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 8,361 $ — $ — $ 8,361 Canadian Government agency debt securities — 4,425 — 4,425 Investments: Commercial paper — 27,844 — 27,844 Corporate bonds — 15,136 — 15,136 Canadian Government agency debt securities — 15,070 — 15,070 U.S. Government agency debt securities — 136,447 — 136,447 $ 8,361 $ 198,922 $ — $ 207,283 Fair Value Measurements as of Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 4,241 $ — $ — $ 4,241 U.S. Government agency debt securities — 5,974 — 5,974 Investments: Commercial paper — 28,792 — 28,792 Corporate bonds — 14,342 — 14,342 Municipal bonds — 2,697 — 2,697 Canadian Government agency debt securities — 19,911 — 19,911 U.S. Government agency debt securities — 77,032 — 77,032 $ 4,241 $ 148,748 $ — $ 152,989 During the six months ended June 30, 2023 and the year ended December 31, 2022 , there were no transfers between Level 1, Level 2 and Level 3.

Investments

Investments	6 Months Ended
	Jun. 30, 2023
Investments, Debt and Equity Securities [Abstract]
Investments	5. Investments Investments consisted of the following (in thousands): June 30, 2023 Amortized Cost Fair Value Due within one year or less $ 166,096 $ 166,074 Due after one year through three years 28,653 28,423 $ 194,749 $ 194,497 December 31, 2022 Amortized Cost Fair Value Due within one year or less $ 127,441 $ 127,013 Due after one year through three years 15,802 15,761 $ 143,243 $ 142,774 As of June 30, 2023, the amortized cost and estimated fair value of investments, by contractual maturity, was as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Current Non-Current Commercial paper $ 27,870 $ 1 $ ( 27 ) $ 27,844 $ 27,844 $ — Corporate bonds 15,229 3 ( 96 ) 15,136 7,885 7,251 Canadian Government agency debt securities 14,777 301 ( 8 ) 15,070 15,070 — U.S. Government agency debt securities 136,873 5 ( 431 ) 136,447 115,275 21,172 $ 194,749 $ 310 $ ( 562 ) $ 194,497 $ 166,074 $ 28,423 As of December 31, 2022, the amortized cost and estimated fair value of investments, by contractual maturity, was as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Current Non-Current Commercial paper $ 28,804 $ 10 $ ( 22 ) $ 28,792 $ 28,792 $ — Corporate bonds 14,354 4 ( 16 ) 14,342 9,469 4,873 Municipal bonds 2,705 — ( 8 ) 2,697 2,697 — Canadian Government agency debt securities 20,065 23 ( 177 ) 19,911 19,911 — U.S. Government agency debt securities 77,315 15 ( 298 ) 77,032 66,144 10,888 $ 143,243 $ 52 $ ( 521 ) $ 142,774 $ 127,013 $ 15,761

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	6 Months Ended
	Jun. 30, 2023
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid Expenses and Other Current Assets	6. Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consisted of the following (in thousands): June 30, 2023 December 31, 2022 Prepaid external research and development expenses $ 4,646 $ 3,741 Prepaid insurance — 1,295 Prepaid software subscriptions 602 402 Income tax receivable 269 386 Interest receivable 688 332 Other receivable due from AstraZeneca 1,053 352 Canadian harmonized sales tax receivable 330 592 Other 1,695 509 $ 9,283 $ 7,609

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2023
Payables and Accruals [Abstract]
Accrued Expenses	7. Accrued Expenses Accrued expenses consisted of the following (in thousands): June 30, 2023 December 31, 2022 Accrued employee compensation and benefits $ 3,469 $ 4,140 Accrued external research and development expenses 4,139 4,914 Accrued professional and consulting fees 1,135 916 Unearned grant income 436 591 Other 164 44 $ 9,343 $ 10,605

Debt

Debt	6 Months Ended
	Jun. 30, 2023
Debt Disclosure [Abstract]
Debt	8. Debt Long-term debt, net of discount, consisted of the following (in thousands): June 30, 2023 Principal amount of long‑term debt $ 35,000 Less: Current portion of long‑term debt — Long‑term debt, net of current portion 35,000 Accretion of Final Fee 273 Debt discount ( 781 ) Long‑term debt, net of discount $ 34,492 Loan Agreement On April 4, 2022 (the “Original Closing Date”), the Company entered into a loan and security agreement (the “Loan Agreement”) with Oxford Finance LLC, as collateral agent and lender (the “Lender”). The Lender initially agreed to make available to the Company term loans in an aggregate principal amount of up to $ 75.0 million under the Loan Agreement. The Company plans to use the proceeds of the term loans for working capital and general corporate purposes. The Loan Agreement initially provided a term loan commitment of $ 75.0 million in three potential tranches: (i) a $ 25.0 million Term A loan facility, with $ 10.0 million funded on the Original Closing Date and the remaining $ 15.0 million to be funded at the request of the Company on a one-time basis at any time prior to April 4, 2023, (ii) a $ 25.0 million Term B loan facility to be funded at the request of the Company, subject to certain conditions being met, no later than June 30, 2023, and (iii) a $ 25.0 million Term C loan facility to be funded at the Lender’s sole discretion. The term loan facilities have a maturity date of April 1, 2027 . Initially borrowings under all three loan facilities bear interest at a floating per annum rate equal to the greater of (i) 8.00 % and (ii) the sum of (a) the greater of (x) 1 Month LIBOR Rate and (y) 0.10 % plus (b) 7.90 %. On August 23, 2022, the Company and the Lender entered into a Consent and First Amendment to Loan and Security Agreement to amend certain terms of the Loan Agreement. On September 21, 2022, the Company and the Lender entered into a Second Amendment to Loan and Security Agreement (the “Second Amendment”). The Second Amendment provides a term loan commitment of $ 75.0 million in four potential tranches: (i) a $ 10.0 million Term A loan facility, funded on the Original Closing Date, (ii) a $ 25.0 million Term B loan facility, funded at the request of the Company subject to certain conditions having been met, for which funding took place in connection with the execution of the Second Amendment, (iii) a $ 15.0 million Term C loan facility to be funded at the request of the Company, subject to certain conditions being met, no later than April 4, 2023, and (iv) a $ 25.0 million Term D loan facility to be funded at the Lender’s sole discretion. The term loan facilities have a maturity date of April 1, 2027. The floating per annum rate of interest for borrowings under all four loan facilities was amended to the greater of (i) 8.00 % and (ii) the sum of (a) 1-Month CME Term SOFR (as defined in the Second Amendment), (b) 0.10 % and (c) 7.90 %. Additionally, on March 30, 2023, the Company and the Lender entered into a Third Amendment to Loan and Security Agreement (together with the Loan Agreement, Consent and First Amendment to Loan and Security Agreement, and Second Amendment, the “Amended Loan Agreement”) to amend the availability of the Term C loan facility which is to be funded at the request of the Company, subject to certain conditions being met, no later than March 31, 2024, under the Amended Loan Agreement. As the terms of the amendments were not substantially different than the terms of the Loan Agreement, the amendments were accounted for as a debt modification. Issuance costs paid to the Lender in connection with the amendments were recorded as an additional debt discount and will be amortized to interest expense over the remaining term, together with unamortized original issuance costs, using the effective interest method. The Company is permitted to make interest-only payments on any outstanding amount due under the term loans through June 1, 2025, after which time principal will also be repaid based on an amortization schedule. The Company is obligated to pay a fee equal to 4.00 % of the aggregate amount of the term loans funded (the “Final Fee”), to occur upon the earliest of (i) the maturity date, (ii) the acceleration of the term loans, and (iii) the prepayment of the term loans. The Company accretes the Final Fee that will be due at final repayment to outstanding debt by charges to interest expense over the term of the loans using the effective-interest method. The Company has the option to prepay all, but not less than all, of the outstanding principal balance of the term loans under the Loan Agreement. If the Company prepays all or a portion of the term loans prior to the maturity date, it is obligated to pay the Lender a prepayment fee based on a percentage of the outstanding principal balance of the loans, equal to 3.00% if the payment occurs on or before 12 months after the funding date of the applicable loan, 2.00% if the prepayment occurs more than 12 months after, but on or before 24 months after, the funding date of the applicable loan, or 1.00% if the prepayment occurs more than 24 months after, but on or before 36 months after, the funding date of the applicable loan, and no prepayment fee is required thereafter. The Loan Agreement contains financial covenants that require the Company to maintain certain minimum cash balances generally equal to 55 % of the outstanding principal or 110 % of the outstanding principal in cases where the cash balances are not maintained in accounts pledged as collateral for the benefit of the Lender. The Company was in compliance with all such covenants as of June 30, 2023 . The Loan Agreement contains customary representations, warranties and covenants and also includes customary events of default, including payment defaults, breaches of covenants, change of control and a material adverse change default. Upon the occurrence of an event of default, a default interest rate of an additional 5.00 % per annum may be applied to the outstanding loan balances, and the Lender may declare all outstanding obligations immediately due and payable. The Company’s obligations under the Loan Agreement are collateralized by a first priority security interest in substantially all of its assets. As of June 30, 2023, the estimated future principal payments due were as follows (in thousands): Year Ending December 31, 2023 (six months) $ — 2024 — 2025 10,652 2026 18,261 2027 6,087 $ 35,000 In connection with the Loan Agreement and the funding of the Term A loan facility, the Company issued warrants to the Lender (the “Term A Warrants”) (see Note 9) to purchase an aggregate of 26,110 common shares, equal to 2.00 % of the $ 10.0 million funded from the Term A loan facility divided by the exercise price of $ 7.66 per share. In connection with the funding of the Term B loan facility, the Company issued warrants to the Lender (the “Term B Warrants”) (see Note 9) to purchase an aggregate 170,010 common shares, equal to 2.00 % of the $ 25.0 million funded from the Term B loan facility divided by the exercise price of $ 2.94 per share. The Company is obligated to issue additional warrants (the “Additional Warrants”) to the Lender in the event the Term C loan facility and/or the Term D loan facility is funded. The Additional Warrants will also be equal to 2.00 % of the term loan funded. Each warrant will terminate ten years from the date of its original issuance. The Company accounted for the Term A Warrants and Term B Warrants as equity instruments since they were indexed to the common shares and met the criteria for equity classification. The relative fair value of the Term A Warrants and Term B Warrants were $ 0.1 million and $ 0.4 million, respectively, and were recorded as a debt discount. This amount is being amortized to interest expense over the term of the loans using the effective-interest method. The Company estimated the fair value of the Term A Warrants and Term B Warrants using the Black-Scholes option-pricing model.

Equity

Equity	6 Months Ended
	Jun. 30, 2023
Equity [Abstract]
Equity	9. Equity Common Shares On May 10, 2023, the Company entered into a Securities Purchase Agreement (the “May 2023 Purchase Agreement”) with the purchasers named therein (the “May 2023 Investors”). Pursuant to the May 2023 Purchase Agreement, the Company agreed to sell an aggregate of 4,784,689 of its common shares, no par value per share, at a purchase price of $ 4.18 per share, to the May 2023 Investors for net proceeds of approximately $ 20.0 million after deducting fees and offering costs (collectively, the “May 2023 Offering”). The May 2023 Offering closed on May 15, 2023. On February 13, 2023, the Company entered into a Securities Purchase Agreement (the “February 2023 Purchase Agreement”) with the purchasers named therein (the “February 2023 Investors”). Pursuant to the February 2023 Purchase Agreement, the Company agreed to sell an aggregate of 17,648,596 of its common shares, no par value per share, at a purchase price of $ 3.40 per share, to the February 2023 Investors for net proceeds of approximately $ 56.0 million after deducting fees and offering costs (collectively, the “February 2023 Offering”). The February 2023 Offering closed on February 16, 2023. In July 2021, the Company entered into an Open Market Sales Agreement SM (the “Sales Agreement”) with Jefferies LLC to issue and sell common shares of up to $ 100.0 million in gross proceeds, from time to time during the term of the Sales Agreement, through an “at-the-market” equity offering program under which Jefferies LLC will act as the Company’s agent and/or principal (the “ATM Facility”). The ATM Facility provides that Jefferies LLC will be entitled to compensation for its services in an amount of up to 3.0 % of the gross proceeds of any shares sold under the ATM Facility. The Company has no obligation to sell any shares under the ATM Facility and may, at any time, suspend solicitation and offers under the Sales Agreement. As of June 30, 2023, the Company has sold 3,211,011 common shares for net proceeds of $ 13.6 million under the Sales Agreement. As of June 30, 2023, the Company’s articles of the corporation, as amended and restated, authorized the Company to issue unlimited common shares, each with no par value per share. Each common share entitles the holder to one vote on all matters submitted to a vote of the Company’s shareholders. Common shareholders are entitled to receive dividends, if any, as may be declared by the board of directors. Through June 30, 2023 , no cash dividends had been declared or paid by the Company. Warrants In January 2020, the Company issued to the existing holders of Class B convertible preferred shares warrants to purchase 3,126,391 Class B convertible preferred shares, at an exercise price of $ 1.5154 per share, and Fusion Pharmaceuticals (Ireland) Limited, the Company’s former Irish subsidiary, issued to the existing holders of Class B preferred exchangeable shares warrants to purchase 873,609 Class B preferred exchangeable shares, at an exercise price of $ 1.5154 per share (collectively the “Preferred Share Warrants”). The Preferred Share Warrants were immediately exercisable and expire two years from the date of issuance or upon the earlier occurrence of specified qualifying events. Upon the closing of the IPO, the warrants to purchase the convertible preferred shares and warrants to purchase the preferred exchangeable shares of the Company’s former Irish subsidiary were converted into warrants to purchase 749,197 common shares at an exercise price of $ 8.10 per share. In January 2022, the remaining 651,816 of unexercised common share warrants expired. In April 2022, in connection with the Loan Agreement with Oxford Finance LLC (see Note 8) and the funding of the Term A loan facility, the Company issued warrants to the Lender to purchase an aggregate of 26,110 common shares, equal to 2.00 % of the $ 10.0 million funded from the Term A loan facility divided by the exercise price of $ 7.66 per share. In September 2022, the Term B loan facility was funded by Oxford Finance LLC and the Company issued warrants to the Lender to purchase an aggregate of 170,010 common shares, equal to 2.00 % of the $ 25.0 million funded from the Term B loan facility divided by the exercise price of $ 2.94 per share. The Company is obligated to issue additional warrants to the Lender in the event the Term C loan facility and/or the Term D loan facility is funded. As of June 30, 2023, there were 196,120 common share warrants outstanding.

Share-Based Compensation

Share-Based Compensation	6 Months Ended
	Jun. 30, 2023
Share-Based Payment Arrangement [Abstract]
Share-Based Compensation	10. Share-based Compensation 2020 Stock Option and Incentive Plan On June 18, 2020, the Company’s board of directors adopted the 2020 Stock Option and Incentive Plan (the “2020 Plan”), which became effective on June 24, 2020. The 2020 Plan provides for the grant of incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock units, restricted stock awards, unrestricted stock awards, cash-based awards and dividend equivalent rights to the Company’s officers, employees, non-employee directors and consultants. The number of shares initially reserved for issuance under the 2020 Plan was 4,273,350 , which is cumulatively increased each January 1 by 4 % of the number of the Company’s common shares outstanding on the immediately preceding December 31 or such lesser number of shares determined by the Company’s compensation committee of the board of directors . The common shares underlying any awards that are forfeited, cancelled, held back upon exercise or settlement of an award to satisfy the exercise price or tax withholding, reacquired by the Company prior to vesting, satisfied without the issuance of shares, expire or are otherwise terminated (other than by exercise) under the 2020 Plan and the Company’s 2017 Equity Incentive Plan (the “2017 Plan”) will be added back to the common shares available for issuance under the 2020 Plan. The total number of common shares reserved for issuance under the 2020 Plan was 10,073,496 shares as of June 30, 2023. As of June 30, 2023, 1,436,819 shares remained available for future grant under the 2020 Plan. Shares that are expired, forfeited, canceled or otherwise terminated without having been fully exercised will be available for future grant under the 2020 Plan. 2017 Equity Incentive Plan The 2017 Plan provides for the Company to grant incentive stock options or nonqualified stock options, restricted share awards and restricted share units to employees, officers, directors and non-employee consultants of the Company. As of June 30, 2023 and December 31, 2022 , no shares remained available for future grant under the 2017 Plan. Shares that are expired, forfeited, canceled or otherwise terminated without having been fully exercised will be available for future grant under the 2020 Plan. 2020 Employee Share Purchase Plan On June 18, 2020, the Company’s board of directors adopted the 2020 Employee Share Purchase Plan (the “ESPP”), which became effective on June 24, 2020. A total of 450,169 common shares were reserved for issuance under this plan. In addition, the number of common shares that may be issued under the ESPP is automatically increased each January 1 by the lesser of (i) 900,338 common shares, (ii) 1 % of the number of the Company’s common shares outstanding on the immediately preceding December 31 and (iii) such lesser number of shares as determined by the Company’s compensation committee of the board of directors. As of June 30, 2023, 43,857 shares were issued under the ESPP. The total number of common shares reserved for issuance under the ESPP was 1,746,220 shares as of June 30, 2023. Stock Option Valuation The fair value of stock option grants is estimated using the Black-Scholes option-pricing model. The Company historically has been a private company and lacks company-specific historical and implied volatility information. Therefore, it estimates its expected share volatility based on the historical volatility of a publicly traded set of peer companies and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded share price. For options with service-based vesting conditions, the expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The expected term of stock options granted to non-employee consultants is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. The following table presents, on a weighted-average basis, the assumptions used in the Black-Scholes option-pricing model to determine the grant-date fair value of stock options granted: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Risk-free interest rate 3.69 % 3.27 % 3.83 % 1.79 % Expected term (in years) 5.9 5.8 6.0 5.7 Expected volatility 66.6 % 67.8 % 65.4 % 62.4 % Expected dividend yield 0 % 0 % 0 % 0 % Stock Options The following table summarizes the Company’s stock option activity since December 31, 2022: Number of Weighted- Weighted- Aggregate (in years) (in thousands) Outstanding as of December 31, 2022 10,531,555 $ 7.08 7.5 $ 4,434 Granted 4,315,000 3.76 Exercised ( 3,221 ) 3.55 Forfeited/cancelled ( 684,341 ) 7.15 Outstanding as of June 30, 2023 14,158,993 $ 6.06 7.9 $ 14,399 Vested and expected to vest as of June 30, 2023 14,067,927 $ 6.03 7.9 $ 14,399 Options exercisable as of June 30, 2023 6,378,773 $ 6.69 6.6 $ 8,210 Included in the table above are 2,726,850 options outstanding as of June 30, 2023 that were granted outside of the 2020 Plan. The grants were made pursuant to the NASDAQ inducement grant exception in accordance with NASDAQ Listing Rule 5635(c)(4). The aggregate intrinsic value of options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common shares for those options that had exercise prices lower than the fair value of the Company’s common shares. The intrinsic value for stock options exercised during the six months ended June 30, 2023 and 2022 was less than $ 0.1 million and $ 0.3 million, respectively. The weighted-average grant-date fair value of stock options granted during the six months ended June 30, 2023 and 2022 was $ 2.35 and $ 4.33 per share, respectively. Restricted Stock Units The following table summarizes the Company’s restricted stock unit activity since December 31, 2022: Number of Weighted- Unvested as of December 31, 2022 65,500 $ 5.91 Granted — — Vested — — Forfeited — — Unvested as of June 30, 2023 65,500 $ 5.91 Share-based Compensation Share-based compensation expense was classified in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Research and development expenses $ 1,111 $ 933 $ 2,249 $ 1,818 General and administrative expenses 1,935 1,803 3,946 3,551 $ 3,046 $ 2,736 $ 6,195 $ 5,369 As of June 30, 2023, total unrecognized share-based compensation expense related to unvested stock options was $ 24.7 million, which is expected to be recognized over a weighted-average period of 2.9 years. Additionally, as of June 30, 2023, the Company has unrecognized share-based compensation expense of $ 0.7 million related to unvested stock options with performance-based vesting conditions for which performance has not been deemed probable. As of June 30, 2023, total unrecognized share-based compensation expense related to unvested restricted stock units was $ 0.3 million, which is expected to be recognized over a weighted-average period of 1.8 years.

License Agreements and Asset Ac

License Agreements and Asset Acquisitions	6 Months Ended
	Jun. 30, 2023
License Agreement [Abstract]
License Agreements and Asset Acquisitions	11. License Agreements and Asset Acquisitions License Agreement with the Centre for Probe Development and Commercialization Inc. In November 2015, the Company entered into a license agreement with the Centre for Probe Development and Commercialization Inc. (“CPDC”), a related party (see Note 16) (the “CPDC Agreement”). Under the CPDC Agreement, the Company was granted an exclusive, sublicensable, nontransferable, worldwide license under CPDC’s patent rights related to CPDC’s radiopharmaceutical linker technology to develop, market, make, use and sell certain products for all disease indications and uses in humans, whether diagnostic or therapeutic. The Company has the right to grant sublicenses of its rights. The CPDC Agreement was amended in 2017; however, there were no material changes to the terms of the CPDC Agreement. Also in 2017, the Company entered into a second license agreement with CPDC, under which the Company was granted an exclusive, sublicensable, worldwide license under CPDC’s patent rights related to certain CPDC radiopharmaceutical linker technology to develop, market, make, use and sell certain products for all disease indications and uses in humans. The Company has the right to grant sublicenses of its rights. The Company has no obligations under any of the agreements with CPDC to make any milestone payments or to pay any royalties or annual maintenance fees to CPDC. During the three and six months ended June 30, 2023 and 2022 , the Company did no t make any payments to CPDC or recognize any research and development expenses under the license agreements with CPDC. License Agreement with ImmunoGen, Inc. In December 2016, the Company entered into a license agreement with ImmunoGen, Inc. (“ImmunoGen”) (the “ImmunoGen Agreement”). Under the ImmunoGen Agreement, the Company was granted an exclusive, sublicensable, worldwide license under ImmunoGen’s patent rights to use, develop, manufacture and commercialize any radiopharmaceutical conjugate that includes a certain compound and any resulting commercialized products. The Company has the right to grant sublicenses of its rights. Under the ImmunoGen Agreement, the Company paid an upfront fee of $ 0.2 million to ImmunoGen. In addition, the Company is obligated to make aggregate milestone payments to ImmunoGen of up to $ 15.0 million upon the achievement of specified development and regulatory milestones and of up to $ 35.0 million upon the achievement of specified sales milestones. The Company is also obligated to pay tiered royalties of a low to mid single-digit percentage based on annual net sales by the Company and any of its affiliates and sublicensees. Royalties will be paid by the Company on a country-by-country basis beginning upon the first commercial sale in such country until ten years following the date of the first commercial sale in the United States and five years following the date of the first commercial sale in all non-U.S. countries. In addition, the Company is responsible for all costs and expenses incurred related to the development, manufacture, regulatory approval and commercialization of all licensed products. Prior to regulatory approval of a licensed product in any country, the Company has the right to terminate the agreement upon 90 days’ prior written notice to ImmunoGen. Upon receipt of its first regulatory approval of a licensed product in any country, the Company has the right to terminate the agreement upon 180 days’ prior written notice to ImmunoGen. If the Company or ImmunoGen fails to comply with any of its obligations or otherwise breaches the agreement, the other party may terminate the agreement. The ImmunoGen Agreement expires upon the expiration date of the last-to-expire royalty term. During the three and six months ended June 30, 2023 and 2022 , the Company did no t make any payments to ImmunoGen or recognize any research and development expenses under the ImmunoGen Agreement. Asset Acquisition from Rainier Therapeutics, Inc. and License Agreement with Genentech, Inc. In March 2020 (the “Closing”), the Company and Rainier Therapeutics, Inc. (“Rainier”) entered into an asset acquisition agreement (the “Rainier Agreement”). Under the Rainier Agreement, the Company purchased all rights, title and interest to Rainier’s, and any of its affiliates’ and sublicensees’, patents and other tangible and intangible assets to perform research and to develop, manufacture and commercialize a specified compound of antibody molecules that bind to targets for the prevention, treatment and diagnosis of all diseases and conditions only using such compound as an antibody drug conjugate. The Company concluded to account for this purchase as an asset acquisition as substantially all of the fair value of the gross assets acquired was concentrated in a single identifiable asset. In connection with the asset acquisition, the Company paid an upfront fee of $ 1.0 million to Rainier and recognized this amount as research and development expense in the condensed consolidated statement of operations and comprehensive loss during the year ended December 31, 2020, as the IPR&D acquired had no alternative future use as of the acquisition date. Unless the Rainier Agreement was terminated pursuant to its terms, which termination initially could not have occurred later than eight months following the Closing (the “Outside Date”), the Company was obligated to pay Rainier an additional amount of $ 3.5 million and to issue 313,359 of the Company’s common shares on the Outside Date. Since the Rainier Agreement was not terminated by the Outside Date, as further described below, the Company is also obligated to make aggregate milestone payments to Rainier of up to $ 22.5 million and to issue up to 156,679 of the Company’s common shares upon the achievement of specified development and regulatory milestones and of up to $ 42.0 million upon the achievement of specified sales milestones. In the event the Company enters into a transaction with a non-affiliated party relating to the license or sale of substantially all the Company’s rights to develop the specified compound of antibody molecules, the Company will be obligated to pay Rainier a specified percentage of the revenue from such transaction, in an amount ranging from 10 % to 30 %, based on how long after the Closing the transaction takes place. The Rainier Agreement could have been terminated at any time prior to the Outside Date upon 30 days’ notice by the Company to Rainier or upon the mutual written consent of both parties. In October 2020, the Company and Rainier entered into a first amendment to the Rainier Agreement (the “First Amended Rainier Agreement”) to extend certain terms of the Rainier Agreement. Specifically, the Outside Date was amended such that termination may not occur later than eleven months following the Closing, or February 10, 2021 (the “Revised Outside Date”). In February 2021, the Company and Rainier entered into a second amendment to the First Amended Rainier Agreement, as amended (the “Second Amended Rainier Agreement”). Pursuant to the Second Amended Rainier Agreement, the Outside Date was further amended such that termination may not occur later than July 1, 2021, and such amendment was made in consideration for early payment of the additional $ 3.5 million owed to Rainier which the Company paid and recorded as research and development expense during the year ended December 31, 2021. In May 2021, the Company notified Rainier of its intent to continue development of the asset and issued 313,359 of its common shares to Rainier on July 1, 2021. In August 2022, the Company announced the dosing of the first patient in a Phase 1 study of FPI-1966 and paid a $ 2.0 million milestone payment and issued 156,679 common shares to Rainier. In May 2023, the Company ceased further clinical development of FPI-1966 as a result of a portfolio prioritization decision. During the three and six months ended June 30, 2023 and 2022 , the Company did no t recognize any research and development expense associated with the Second Amended Rainier Agreement. In connection with the Rainier Agreement, in March 2020, the Company was assigned all of Rainier’s rights and obligations under an exclusive license agreement between BioClin Therapeutics, Inc. and Genentech, Inc. (“Genentech”) (the “Genentech License Agreement”). Pursuant to the Genentech License Agreement, the Company has an exclusive, worldwide, sublicensable license to make, use, research, develop, sell and import certain intellectual property and technology of Genentech relating to a specified antibody and any mutant antibody thereof (the “Licensed Antibodies”), including any products that contain a Licensed Antibody as an active ingredient (the “Products”), for all human uses. Pursuant to the Genentech License Agreement, the Company is obligated to use commercially reasonable efforts to develop and commercialize at least one Product and the Company is solely responsible for the costs associated with the development, manufacturing, regulatory approval and commercialization of any Products. The manufacture of the antibody by any third-party contract development and manufacturing organization (“CDMO”) must be approved in advance by Genentech. Additionally, Genentech retains the right to use the Licensed Antibodies solely to research and develop molecules other than the Licensed Antibodies. Under Genentech License Agreement, the Company is obligated to make aggregate milestone payments to Genentech of up to $ 44.0 million upon the achievement of specified sales milestones. The Company is also obligated to pay to Genentech tiered royalties of a mid to high single-digit percentage based on annual net sales by the Company, and any of its affiliates and sublicensees, for the specified compound of antibody molecules and of a mid to high single-digit percentage based on annual net sales by the Company, and any of its affiliates and sublicensees, for any other compound containing mutant antibody molecules of the specified compound. In addition, the Company is obligated to pay to Genentech royalties of a low single-digit percentage based on quarterly net sales in any country in which the specified compound is not covered by a valid patent claim, and those sales will not be subject to the tiered royalties described above. All royalties may be reduced if the Company obtains a license under a third-party patent that includes the specified compound. Royalties will be paid by the Company on a country-by-country basis beginning upon the first commercial sale in such country until the later of (i) ten years following the date of the first commercial sale of a Product or (ii) the date the specified compound is no longer covered by an enforceable patent. Upon the expiration of the royalty term, the Company will have a fully paid-up license. The Company has the right to terminate the Genentech License Agreement upon written notice to Genentech if the Company determines in its sole discretion that development or commercialization of Products is not economically or scientifically feasible or appropriate. In addition, if the Company or Genentech fails to comply with any of its obligations or otherwise breaches the agreement, the other party may terminate the agreement. The Genentech License Agreement expires on the date on which all obligations under the agreement related to milestone payments or royalties have passed or expired. In May 2023, the Company ceased further clinical development of FPI-1966 as a result of a portfolio prioritization decision. During the three and six months ended June 30, 2023 and 2022 , the Company did no t make any payments to Genentech or recognize any research and development expenses under the Genentech License Agreement. Collaboration Agreement and Supply Agreement with TRIUMF Innovations, Inc. On December 10, 2020, the Company entered into a Collaboration Agreement and Supply Agreement (the “Collaboration Agreement”) with TRIUMF Innovations Inc. and TRIUMF JV (collectively, “the TRIUMF entities”) for the development, production and supply of actinium-225 (“ 225 Ac”) to the Company. Under the Collaboration Agreement as executed in December 2020, the Company is obligated to pay the TRIUMF entities an aggregate of $ 5.0 million CAD upon the achievement of certain milestones. The Collaboration Agreement contemplated that the parties would enter into an amendment thereto to expand the scope of the project and provide for additional milestone payments. As of June 30, 2023 , the TRIUMF entities had achieved certain milestones under the Collaboration Agreement totaling $ 3.0 million CAD (equivalent to $ 2.3 million at the time of payment) which were paid during the year ended December 31, 2021 and are being recognized as research and development expense over the period of performance by the TRIUMF entities. During each of the three and six months ended June 30, 2023 and 2022 , the Company recognized the amortization of less than $ 0.1 million as research and development expense under the Collaboration Agreement. As previously contemplated, on August 12, 2021, the parties amended the Collaboration Agreement in order to expand the scope of the project and the Company agreed to make an additional financial investment of up to $ 15.0 million CAD in connection with development of new process technology for the manufacture of 225 Ac upon the achievement of certain milestones under an amendment to the Collaboration Agreement (the “Amended Collaboration Agreement”). In connection with the Amended Collaboration Agreement, the parties have formed a company (“NewCo”) to hold certain intellectual property derived from the collaboration. NewCo is jointly owned and managed by the Company and the TRIUMF entities and its purpose is to manufacture 225 Ac for the research, clinical and commercial needs of the Company, and in certain circumstances, other third parties. The supply of 225 Ac by NewCo to the Company shall be done under a commercial supply agreement, to be negotiated by NewCo and the Company. The Company is expected to purchase at least 50 % of its annual 225 Ac requirements from NewCo, unless NewCo is unable to supply such necessary quantities to the Company, in which case the Company may use other 225 Ac suppliers to meet its commercial needs. As of June 30, 2023 , there were no assets held by NewCo. As of June 30, 2023 , the TRIUMF entities had achieved certain milestones under the Amended Collaboration Agreement totaling $ 8.5 million CAD (equivalent to $ 6.6 million at the time of payment), of which $ 2.6 million was paid during the year ended December 31, 2022 and $ 3.9 million was paid during the year ended December 31, 2021. These amounts are being recognized as research and development expense over the period of performance by the TRIUMF entities. During the three and six months ended June 30, 2023 , the Company recognized the amortization of $ 0.5 million and $ 0.8 million, respectively, as research and development expense under the Amended Collaboration Agreement. During the three and six months ended June 30, 2022 , the Company recognized the amortization of $ 0.4 million and $ 0.5 million, respectively, as research and development expense under the Amended Collaboration Agreement. The Company recorded $ 2.1 million and $ 1.6 million of milestone payments in prepaid expenses and other current assets and other non-current assets, respectively, as of June 30, 2023 based on its estimate of costs to be incurred over the 12 months following the balance sheet date for both the Collaboration Agreement and the Amended Collaboration Agreement. Asset Acquisition from Ipsen Pharma SAS In March 2021, the Company and Ipsen Pharma SAS (“Ipsen”) announced that the parties had entered into an asset purchase agreement (the “Ipsen Agreement”) whereby the Company agreed to acquire Ipsen’s intellectual property and assets related to IPN-1087, a small molecule targeting neurotensin receptor 1 (“NTSR1”), a protein expressed on multiple solid tumor types. The Company intends to combine its expertise and proprietary TAT platform with IPN-1087 to create an alpha-emitting radiopharmaceutical targeting solid tumors expressing NTSR1. The Company and Ipsen submitted a pre-merger notification and report form with the United States Federal Trade Commission and the Antitrust Division of the United States Department of Justice in accordance with the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the “HSR Act”). The acquisition closed after completion of this antitrust review in April 2021. The Company concluded to account for this purchase as an asset acquisition as substantially all of the fair value of the gross assets acquired was concentrated in a single identifiable asset. Upon closing of the asset acquisition, the Company paid € 0.6 million ($ 0.8 million at the date of payment) and issued an aggregate of 600,000 common shares to Ipsen under a share purchase agreement which was entered into concurrently with the Ipsen Agreement. Such common shares were issued pursuant to an exemption from the registration requirements of the Securities Act of 1933, as amended (the “Securities Act”). The Company is also obligated to pay Ipsen up to an additional € 67.5 million upon the achievement of certain development and regulatory milestones; low single digit royalties on potential future net sales; and up to € 350.0 million in net sales milestones, in each case, relating to products covered by the asset purchase agreement. The Company is responsible for paying to a third-party licensor up to a total of € 70.0 million in development milestones for up to three indications and mid to low double-digit royalties on potential future net sales of products covered by the license agreement. During the three and six months ended June 30, 2023 and 2022 , the Company did no t make any payments to Ipsen or recognize any research and development expenses under the Ipsen Agreement. The Ipsen Agreement includes a royalty step down whereby royalties owed to Ipsen will be reduced by certain percentages not to exceed 50 %, in the aggregate, of the royalty owed under certain circumstances relating to loss of patent exclusivity, loss of regulatory exclusivity or generics entering a market. Under the asset purchase agreement Ipsen has agreed not to develop a molecule that targets NTSR1 and combines at least one NTSR1 binding moiety and a radionuclide or cytotoxic agent until the earlier of (i) the seventh anniversary of the closing date or (ii) the date of data base lock after completion of the first phase 3 clinical trial for IPN-1087. Agreement with Merck & Co. In May 2021, the Company entered into an agreement with two subsidiaries of Merck & Co. (“Merck”). Pursuant to the agreement, Merck will provide to the Company, at no cost, its anti-PD-1 (programmed death receptor-1) therapy, KEYTRUDA® (pembrolizumab) to evaluate in combination with the Company’s lead candidate, FPI-1434. The planned Phase 1 combination trial will evaluate safety, tolerability and pharmacokinetics of FPI-1434 in combination with pembrolizumab and is expected to initiate approximately six to nine months after achieving the recommended Phase 2 dose in the ongoing Phase 1 study of FPI-1434 monotherapy. Under the agreement, the Company will sponsor, fund and conduct the combination trial in accordance with an agreed-upon protocol and Merck agreed to manufacture and supply its compound, at its cost and for no charge to the Company, for use in the clinical trial. Collaboration and Supply Agreement with Niowave, Inc. On June 9, 2022, the Company entered into a Collaboration and Supply Agreement with Niowave, Inc. (“Niowave”) (as amended from time to time, the “Niowave Agreement”) for the development, production and supply of 225 Ac to the Company. Under the Niowave Agreement, the Company is obligated to pay Niowave an aggregate of $ 5.0 million upon the achievement of certain milestones. On September 26, 2022, the Company entered into an amendment to the Niowave Agreement to amend certain terms of the Niowave Agreement, but made no change to the aggregate milestone payments owed under the Niowave Agreement. As of June 30, 2023 , Niowave had achieved certain milestones under the Niowave Agreement totaling $ 2.8 million, of which $ 1.9 million was paid during the six months ended June 30, 2023 and $ 0.9 million was paid during the year ended December 31, 2022. These amounts are being recognized as research and development expense over the period of performance by Niowave. During the three and six months ended June 30, 2023 , the Company recognized $ 0.5 million and $ 0.7 million, respectively, as research and development expense under the Niowave Agreement. During the three and six months ended June 30, 2022 , the Company recognized $ 0.1 million as research and development expense under the Collaboration and Supply Agreement. The Company recorded $ 1.2 million of milestone payments in prepaid expenses and other current assets as of June 30, 2023 based on its estimate of costs to be incurred over the 12 months following the balance sheet date for the Niowave Agreement. RadioMedix Option and Asset Purchase Agreement On November 14, 2022, the Company and RadioMedix, Inc. (“RadioMedix”) entered into an option and asset purchase agreement (the “RadioMedix Agreement”), pursuant to which RadioMedix granted to the Company the exclusive right, but not the obligation (the “RadioMedix Option”), to acquire certain of RadioMedix’s assets related to its on-going Phase 2 clinical trial evaluating 225 Ac PSMA I&T (the “TATCIST Study”), a small molecule targeting prostate specific membrane antigens, expressed on prostate tumors. Such assets include, among other things, the investigational new drug application for the TATCIST Study, any third-party license held, or later acquired, by RadioMedix relating to 225 Ac PSMA, and clinical and other data for the TATCIST Study (collectively, the “RadioMedix Assets”). The Company paid RadioMedix an option fee of $ 0.8 million upon the execution of the RadioMedix Agreement, which was recorded as research and development expense in its consolidated statements of operations and comprehensive loss during the year ended December 31, 2022. On February 10, 2023, the Company notified RadioMedix of its decision to exercise the RadioMedix Option, paid the $ 1.5 million option exercise fee and closed the acquisition. During the six months ended June 30, 2023 , the Company recognized the $ 1.5 million option exercise fee as research and development expense under the RadioMedix Agreement. The alpha-emitting radiopharmaceutical being evaluated in the TATCIST Study is now referred to as FPI-2265. Pursuant to the terms of the RadioMedix Agreement, the Company is obligated to pay RadioMedix (i) up to an additional $ 10.5 million upon the achievement of certain clinical and regulatory milestones, (ii) low single-digit royalties on potential future net sales, subject to specified reductions, and (iii) up to an additional $ 50.0 million in net sales milestones; in each case, relating to products covered by the RadioMedix Agreement. In addition, in the event RadioMedix or the Company is successful in obtaining certain intellectual property rights from a third party relating to 225 Ac PSMA I&T, the amount of the clinical and regulatory milestone payments will be increased by up to an aggregate of $ 4.0 million and the royalty rates will increase but remain in the low- to mid-single digits. Pursuant to the RadioMedix Agreement, the Company is prohibited from terminating or deprioritizing the development of 225 Ac PSMA I&T, subject to specified exceptions. If the Company terminates or deprioritizes the development of 225 Ac PSMA I&T, and does not sell, license or otherwise transfer its rights to a third-party within 12 months of such termination, the Company and RadioMedix are required to negotiate the return of 225 Ac PSMA I&T and related assets to RadioMedix in return for specified reimbursement costs to the Company. RadioMedix has agreed, subject to certain exceptions, not to develop or research a molecule that targets PSMA for a certain period of time following the closing date. Additionally, the Company and RadioMedix have entered into manufacturing agreements under which RadioMedix will supply FPI-2265 to the Company for use in clinical trials. RadioMedix will not be the sole manufacturer to supply FPI-2265 for use in clinical trials. Asset Purchase Agreement with Undisclosed Third-Party On June 1, 2023, the Company and an undisclosed, unrelated third-party entered into an asset purchase agreement (the “Third-Party Agreement”), pursuant to which the undisclosed third-party granted to the Company the rights to all know-how and information related to an unspecified target, including governmental authorizations, regulatory materials, books and records, patents, third party claims and causes of action, and all other assets, rights and properties. The Company concluded to account for this purchase as an asset acquisition as substantially all of the fair value of the gross assets acquired was concentrated in a single identifiable asset. During the three and six months ended June 30, 2023 , the Company paid an upfront payment of $ 0.7 million under the Third-Party Agreement which was recognized as research and development expense. Pursuant to the terms of the Third-Party Agreement, the Company is obligated to pay (i) up to an additional $ 7.5 million upon the achievement of certain clinical and regulatory milestones, (ii) low single-digit royalties on potential future net sales, subject to specified reductions, and (iii) up to an additional $ 50.0 million in net sales milestones; in each case, relating to products covered by the Third-Party Agreement.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	12. Income Taxes The Company is domiciled in Canada and is primarily subject to taxation in that country. During the three and six months ended June 30, 2023 and 2022 , the Company recorded no income tax benefits for the net operating losses incurred or for the research and development tax credits generated in Canada in each period due to its uncertainty of realizing a benefit from those items. During the three and six months ended June 30, 2023 , the Company recorded a tax benefit of $ 0.2 million and $ 0.3 million, respectively, primarily related to the Company’s foreign-derived intangible income deduction, partially offset by discrete share-based compensation items. Under the Tax Cuts and Jobs Act, taxpayers can no longer immediately expense qualified research and development expenditures. Taxpayers are now required to capitalize and amortize these costs over five years for research conducted within the United States or 15 years for research conducted abroad. As a result, the capitalization requirement increased the Company’s deferred tax assets and current tax liabilities, but also decreased its effective tax rate by increasing the foreign-derived intangible income deduction. During the three and six months ended June 30, 2022 , the Company recorded a tax benefit of $ 0.7 million, primarily related to discrete share-based compensation items and return to provision adjustments arising during these periods from its operating company in the U.S. The Company’s tax provision and the resulting effective tax rate for interim periods is determined based upon its estimated annual effective tax rate (“AETR”), adjusted for the effect of discrete items arising in that quarter. The impact of such inclusions could result in a higher or lower effective tax rate during a particular quarter, based upon the mix and timing of actual earnings or losses versus annual projections. In each quarter, the Company updates its estimate of the annual effective tax rate, and if the estimated annual tax rate changes, a cumulative adjustment is made in that quarter. For the three and six months ended June 30, 2023 and 2022, the Company excluded Canada from the calculation of the AETR as the Company anticipates an ordinary loss in this jurisdiction for which no tax benefit can be recognized. The Company has evaluated the positive and negative evidence bearing upon its ability to realize its deferred tax assets both in the United States and Canada, which primarily consist of net operating loss carryforwards in Canada. The Company has considered its history of cumulative net losses in Canada, estimated future taxable income and prudent and feasible tax planning strategies and has concluded that it is more likely than not that the Company will not realize the benefits of its Canadian deferred tax assets. As a result, as of June 30, 2023 and December 31, 2022 , the Company has recorded a full valuation allowance against its net deferred tax assets in Canada.

Net Loss per Share

Net Loss per Share	6 Months Ended
	Jun. 30, 2023
Earnings Per Share [Abstract]
Net Loss per Share	13. Net Loss per Share Net Loss per Share Attributable to Common Shareholders Basic and diluted net loss per share attributable to common shareholders was calculated as follows (in thousands, except share and per share amounts): Three Months Ended Six Months Ended 2023 2022 2023 2022 Numerator: Net loss $ ( 25,175 ) $ ( 19,073 ) $ ( 49,466 ) $ ( 38,982 ) Denominator: Weighted-average common shares outstanding—basic and diluted 66,277,279 43,357,240 60,061,166 43,264,175 Net loss per share attributable to common shareholders —basic $ ( 0.38 ) $ ( 0.44 ) $ ( 0.82 ) $ ( 0.90 ) The Company’s potentially dilutive securities, which include stock options and common share warrants, have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted-average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common shareholders is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common shareholders for the periods indicated because including them would have had an anti-dilutive effect: Six Months Ended 2023 2022 Options to purchase common shares 14,158,993 9,924,748 Unvested restricted stock units 65,500 73,700 Warrants to purchase common shares 196,120 26,110 14,420,613 10,024,558

Leases

Leases	6 Months Ended
	Jun. 30, 2023
Leases [Abstract]
Leases	14. Leases In August 2018, the Company entered into an operating lease for office space in Hamilton, Ontario. This lease was amended in September 2020 (“New Lease Commencement Date”) and expires in August 2030 with a termination option upon twelve months written notice any time after the fifth anniversary of the New Lease Commencement Date. If the termination option is not exercised, the Company may exercise a renewal option to extend the term for an additional five-year period through August 2035. As the Company is not reasonably certain to extend the lease beyond the allowable termination date, the lease term was determined to end in August 2026 for the purposes of measuring this lease. In October 2019, the Company entered into an operating lease for office space in Boston, Massachusetts, which expires February 2026 and has no renewal options . In connection with entering into the original lease agreement, the Company issued a letter of credit of $ 1.5 million for the benefit of the landlord, which was reduced to $ 1.0 million during the six months ended June 30, 2023. As of June 30, 2023 , $ 0.2 million and $ 0.8 million of the underlying cash balance collateralizing this letter of credit was classified as restricted cash, current and non-current, respectively, on the Company’s condensed consolidated balance sheets based on the release date of the restrictions of this cash. As of December 31, 2022 , $ 0.2 million and $ 1.0 million of the underlying cash balance collateralizing this letter of credit was classified as restricted cash, current and non-current, respectively, on the Company’s condensed consolidated balance sheets based on the release date of the restrictions of this cash. In March 2021, the Company entered into an amendment to its lease for office space in Boston, Massachusetts to expand the area under lease (“Expansion Premises”) and extend the term of the premises currently under lease (“Original Premises”) to align with the lease end date for the Expansion Premises. The additional rent for the Expansion Premises was determined to be commensurate with the additional right-of-use and is accounted for as a new operating lease that was recognized on the Company’s balance sheet since the Company was able to access the Expansion Premises upon execution of the amendment. The Company has made certain improvements to the Expansion Premises, for which the landlord has provided the Company an allowance of $ 0.2 million which was recorded as a reduction to operating lease right-of-use assets and operating lease liabilities as of December 31, 2021, and for which reimbursement was received during the year ended December 31, 2022. The rental payments for the Expansion Space commenced on January 1, 2022. The lease end date for the Original Premises and the Expansion Premises is April 30, 2027, with no option to extend the lease term. The lease modification for the extension of the Original Premises and the recognition of the Expansion Premises resulted in increases to the Company’s right-of-use asset balance, which was obtained in exchange for operating lease liabilities, of $ 0.9 million and $ 1.2 million, respectively. In June 2021, the Company entered into a lease for a manufacturing facility in Hamilton, Ontario. The Company currently expects the rent for the manufacturing facility to commence in the third quarter of 2023. The Company currently expects the lease end date for the manufacturing facility to be in June 2038 . The lease has a five-year renewal option, which the Company is not reasonably certain to exercise and therefore was not included in the expected lease term. Upon execution of the lease in June 2021, the Company paid $ 2.5 million CAD (equivalent to $ 2.1 million at the time of payment) which represented an initial direct cost paid prior to the lease commencement date. The Company determined that the lease is an operating lease and commenced for accounting purposes on March 31, 2023, when the Company obtained access to the space for its’ intended use. In connection with the lease commencement for accounting purposes, the Company recorded an operating right-of-use asset of $ 10.8 million (including the $ 2.1 million payment that was previously recorded to prepaid rent as a component of other non-current assets) obtained in exchange for an operating lease liability of $ 8.9 million. On January 12, 2022, the Company entered into an operating lease for office space in Hamilton, Ontario. This lease was amended and commenced in February 2022 and is set to expire in August 2030 . The lease has a five-year renewal option upon twelve months written notice prior to the expiration of the original term , which the Company is not reasonably certain to exercise and therefore was not included in the lease term for the purposes of measuring the lease. As a result, the Company recognized an operating lease liability and operating lease right-of-use asset of $ 0.3 million at lease commencement in February 2022. From time to time, the Company enters into arrangements with CDMOs for the manufacture of materials for research and development purposes, including the manufacture of clinical trial materials. These contracts generally provide for certain non-cancellable obligations. The Company concluded that one such agreement contains an embedded lease as a controlled environment room at the facility is designated for the Company’s exclusive use during the term of the agreement. Upon the lease commencement in February 2023, the Company recorded an operating right-of-use asset of $ 2.2 million and corresponding operating lease liability of $ 1.5 million. The arrangement expires in March 2025 . The components of operating lease cost, which are included within operating expenses in the accompanying condensed consolidated statements of operations and comprehensive loss, are as follows (in thousands): Three Months Ended Six Months Ended 2023 2022 2023 2022 Operating lease cost $ 994 $ 369 $ 1,490 $ 735 Variable lease cost 127 27 149 40 Total lease cost $ 1,121 $ 396 $ 1,639 $ 775 The following table summarizes supplemental information for the Company’s operating leases: As of June 30, 2023 Weighted-average remaining lease term (in years) 10.2 Weighted average discount rate 11.0 % Cash paid for amounts included in the measurement of lease liabilities (in thousands) $ 1,009 As of June 30, 2023, the future maturities of operating lease liabilities are as follows (in thousands): Year Ending December 31, 2023 (six months) $ 3,934 2024 3,135 2025 2,598 2026 2,357 2027 1,341 Thereafter 13,688 Total lease payments $ 27,053 Less: imputed interest ( 10,923 ) Total lease liabilities $ 16,130

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	15. Commitments and Contingencies Manufacturing Commitments In January 2019, and as amended in September 2020, the Company entered into an agreement with CPDC, a related party (see Note 16), to manufacture clinical trial materials. In August 2022, this agreement was assigned and transferred to a third-party CDMO who is not a related party. As of June 30, 2023, the Company had non-cancelable minimum purchase commitments under the agreement totaling $ 0.4 million over the following twelve months. In May 2019, the Company entered into an agreement with a third-party CDMO to manufacture clinical trial materials. As of June 30, 2023, the Company had non-cancelable minimum purchase commitments under the agreement totaling $ 0.5 million over the following twelve months. On January 26, 2023, the Company entered into an agreement with another third-party CDMO to manufacture clinical trial materials. As of June 30, 2023, the Company had non-cancelable minimum purchase commitments under the agreement totaling $ 0.3 million over the following twelve months. License Agreements The Company has entered into license agreements with various parties under which it is obligated to make contingent and non-contingent payments (see Note 11). Indemnification Agreements In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors and certain of its executive officers that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. The Company is not currently aware of any indemnification claims and has not accrued any liabilities related to such obligations in its condensed consolidated financial statements as of June 30, 2023 or December 31, 2022. Legal Proceedings On February 13, 2023, the Company filed an Inter Partes Review (“IPR”) petition with the United States Patent and Trademark Office (“USPTO”) to challenge the validity of a certain issued U.S. Patent relating to FPI-2265. The Company cannot predict if the IPR will be instituted by the USPTO or, if instituted, the Company will prevail. The Company is not a party to any other litigation and does not have contingency reserves established for any litigation liabilities. At each reporting date, the Company evaluates whether or not a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company expenses as incurred the costs related to such legal proceedings.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2023
Related Party Transactions [Abstract]
Related Party Transactions	16. Related Party Transactions The Company’s chief executive officer, founder and member of the board of directors, John Valliant, Ph.D., is a member of the board of directors at CPDC. Besides the license agreements entered into with CPDC (see Note 11), the Company had also entered into a Master Services Agreement and a Supply Agreement with CPDC, under which CPDC provided services to the Company related to preclinical and manufacturing services, administrative support services and access to laboratory facilities. In connection with the Supply Agreement, the Company was obligated to pay CPDC an amount of $ 0.2 million per quarter, or $ 0.9 million in the aggregate per year, plus fees for materials, packaging and distribution of products supplied to the Company. The Company recognized expenses in connection with the services performed in the normal course of business under the Master Services Agreement and the Supply Agreement in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands): Three Months Ended Six Months Ended 2022 2022 Research and development expenses $ 418 $ 1,408 General and administrative expenses 3 17 $ 421 $ 1,425 In August 2022, CPDC transferred and assigned all agreements (including the Master Services Agreement and the Supply Agreement) other than the license agreements (see Note 11) with the Company to AtomVie, a third-party CDMO, who is not a related party. All terms and conditions of the agreements that were transferred and assigned will remain in full force and effect. CPDC’s performance obligations under these agreements will be undertaken by AtomVie. During the three and six months ended June 30, 2022 , the Company made payments to CPDC in connection with the services described above of $ 0.4 million and $ 1.1 million, respectively. As of June 30, 2023 and December 31, 2022, there were no amounts due to CPDC by the Company in connection with the services described above. In addition to costs incurred in connection with the services described above, the Company also reimbursed CPDC for purchases on the Company’s behalf from parties with which the Company did not have an account. During the three and six months ended June 30, 2022 , the Company made payments to CPDC of less than $ 0.1 million and $ 0.1 million, respectively, for reimbursement of these pass-through costs. During the three and six months ended June 30, 2022 , the Company recorded less than $ 0.1 million and $ 0.2 million, respectively, of lab equipment purchased from CPDC which they acquired from third-party vendors on its behalf.

Geographical Information

Geographical Information	6 Months Ended
	Jun. 30, 2023
Geographic Areas, Long-Lived Assets [Abstract]
Geographical Information	17. Geographical Information The Company has operating companies in the United States and Canada. Information about the Company’s long-lived assets, consisting solely of property and equipment, net, by geographic region was as follows (in thousands): June 30, December 31, United States $ 405 $ 465 Canada 5,304 4,166 $ 5,709 $ 4,631

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. Since inception, the Company has funded its operations primarily with proceeds from sales of its convertible preferred shares, including borrowings under a convertible promissory note, which converted into convertible preferred shares, proceeds from sales of its former Irish subsidiary’s preferred exchangeable shares, proceeds from its initial public offering completed in June 2020, proceeds from its “at-the-market” equity offering program (see Note 9), proceeds from its loan and security agreement with Oxford Finance LLC executed in April 2022 (see Note 8), and proceeds from private placement financings completed in February 2023 and May 2023 (see Note 9). The Company has incurred recurring losses since its inception, including net losses of $ 25.2 million and $ 49.5 million for the three and six months ended June 30, 2023 , respectively, and net losses of $ 19.1 million and $ 39.0 million for the three and six months ended June 30, 2022, respectively. In addition, as of June 30, 2023, the Company had an accumulated deficit of $ 331.3 million. The Company expects to continue to generate operating losses for the foreseeable future. As of the issuance date of these condensed consolidated financial statements, the Company expects that its cash, cash equivalents and investments will be sufficient to fund its operating expenses and capital expenditure requirements for at least the next 12 months. The future viability of the Company is dependent on its ability to raise additional capital to finance its operations.
Impacts of COVID-19 and Market Conditions on Our Business	Impacts of COVID-19 and Market Conditions on Our Business The Company believes its financial results for the three and six months ended June 30, 2023 and year ended December 31, 2022 were not significantly impacted by the COVID-19 pandemic. The Company believes its hybrid and remote working arrangements have had limited impact on its ability to maintain internal operations during the three and six months ended June 30, 2023 and year ended December 31, 2022 . Further, disruption of global financial markets and a recession or market correction, including as a result of the COVID-19 pandemic, the ongoing military conflict between Russia and Ukraine and the related sanctions imposed against Russia, and other global macroeconomic factors such as inflation and the recent banking industry volatility, could reduce the Company’s ability to access capital, which could, in the future, negatively affect its business and the value of its common shares.
Use of Estimates	Use of Estimates The preparation of the Company’s condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, the accrual of research and development expenses, valuations of share-based awards, valuation allowance of deferred tax assets, and revenue recognition. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates when there are changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results may differ from those estimates or assumptions.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying condensed consolidated balance sheet as of June 30, 2023, the condensed consolidated statement of operations and comprehensive loss, and the condensed consolidated statement of shareholders’ equity, and the condensed consolidated statement of cash flows for the three and six months ended June 30, 2023 and 2022 are unaudited. The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of June 30, 2023 and the results of its operations and its cash flows for the three and six months ended June 30, 2023 and 2022. The results for the three and six months ended June 30, 2023 are not necessarily indicative of results to be expected for the year ending December 31, 2023, any other interim periods, or any future year or period. The accompanying balance sheet as of December 31, 2022 has been derived from the Company’s audited financial statements for the year ended December 31, 2022. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to rules and regulations. However, the Company believes that the disclosures are adequate to make the information presented not misleading. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited annual consolidated financial statements as of December 31, 2022 , and notes thereto, which are included in the Company’s Annual Report on Form 10-K that was filed with the SEC on March 16, 2023.
Foreign Currency and Currency Translation	Foreign Currency and Currency Translation The reporting currency of the Company is the U.S. dollar. The functional currency of the Company’s operating company in Canada and operating company in the U.S. is also the U.S. dollar. As a result, the Company records no cumulative translation adjustments related to translation of unrealized foreign exchange gains or losses. For the remeasurement of local currencies to the U.S. dollar functional currency of the Canadian entity, assets and liabilities are translated into U.S. dollars at the exchange rate in effect on the balance sheet date, and income items and expenses are translated into U.S. dollars at the average exchange rate in effect during the period. Resulting transaction gains (losses) are included in other income (expense), net in the condensed consolidated statements of operations and comprehensive loss, as incurred. Adjustments that arise from exchange rate changes on transactions denominated in a currency other than the local currency are included in other income (expense), net in the condensed consolidated statements of operations and comprehensive loss, as incurred. During the three and six months ended June 30, 2023 , the Company recorded $ 0.1 million and $( 0.3 ) million, respectively, of foreign currency gains (losses) in the condensed consolidated statements of operations and comprehensive loss. During the three and six months ended June 30, 2022 , the Company recorded $( 0.6 ) million and $( 0.3 ) million, respectively, of foreign currency (losses) in the condensed consolidated statements of operations and comprehensive loss.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents consist of standard checking accounts, money market accounts, and all highly liquid investments with an original maturity of three months or less at the date of purchase. As of June 30, 2023 and December 31, 2022 , the Company was required to maintain a separate cash balance of $ 0.2 million to collateralize corporate credit cards with a bank, which was classified as restricted cash, current, on its condensed consolidated balance sheets. The Company also maintained a $ 0.1 million guaranteed investment certificate to fulfill certain contractual obligations which was classified as restricted cash, current, as of June 30, 2023 and December 31, 2022. In connection with the Company’s lease agreement entered into in October 2019 (see Note 14), the Company maintained a letter of credit of $ 1.5 million for the benefit of the landlord, which was reduced to $ 1.0 million during the six months ended June 30, 2023. As of June 30, 2023 , $ 0.2 million and $ 0.8 million of the underlying cash balance collateralizing this letter of credit was classified as restricted cash, current and non-current, respectively, on the Company’s condensed consolidated balance sheets based on the release date of the restrictions of this cash. As of December 31, 2022 , $ 0.2 million and $ 1.0 million of the underlying cash balance collateralizing this letter of credit was classified as restricted cash, current and non-current, respectively, on the Company’s condensed consolidated balance sheets based on the release date of the restrictions of this cash. As of June 30, 2023 and December 31, 2022, the cash, cash equivalents and restricted cash of $ 33.3 million and $ 45.3 million, respectively, presented in the condensed consolidated statements of cash flows included cash and cash equivalents of $ 32.0 million and $ 43.9 million, respectively, and restricted cash of $ 1.3 million and $ 1.5 million, respectively.
Investments	Investments The Company adopted ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”) effective January 1, 2023, and the adoption did not have a material impact on its condensed consolidated financial statements. The Company determines the appropriate classification of its investments in debt securities at the time of purchase and re-evaluates such determination at each balance sheet date. The Company classifies its investments as current or non-current based on each instrument’s underlying maturity date. Investments with original maturities of greater than three months and remaining maturities less than twelve months are classified as current and are included in short-term investments in the condensed consolidated balance sheets. Investments with remaining maturities greater than one year from the balance sheet date are classified as non-current and are included in long-term investments in the condensed consolidated balance sheets. The Company’s investments are classified as available-for-sale, are reported at fair value and consist of U.S. and Canadian government agency debt securities, corporate bonds, and commercial paper. Unrealized gains and losses are included in other comprehensive (loss) income as a component of shareholders’ equity until realized. Amortization and accretion of premiums and discounts are recorded in interest income. Realized gains and losses on debt securities are included in other (expense) income, net. The Company reviews its portfolio of available-for-sale debt securities, using both quantitative and qualitative factors, to determine if declines in fair value below cost have resulted from a credit-related loss or other factors. If the decline in fair value is due to credit-related factors, a loss is recognized in net loss, and if the decline in fair value is not due to credit-related factors, the loss is recorded in other comprehensive loss. No credit losses were recorded during the periods presented.
Deferred Offering Costs	Deferred Offering Costs The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of an equity financing, these costs are recorded as a reduction of the proceeds from the offering in shareholders’ equity as a reduction of additional paid-in capital generated as a result of the offering. Should an in-process equity financing be abandoned, the deferred offering costs would be expensed immediately as a charge to operating expenses in the condensed consolidated statements of operations and comprehensive loss. The Company recorded $ 0.1 million and $ 0.2 million of deferred offering costs as of June 30, 2023 and December 31, 2022 , respectively, in other non-current assets.
Collaborative Arrangements	Collaborative Arrangements The Company considers the nature and contractual terms of arrangements and assesses whether an arrangement involves a joint operating activity pursuant to which the Company is an active participant and is exposed to significant risks and rewards dependent on the commercial success of the activity. If the Company is an active participant and is exposed to significant risks and rewards dependent on the commercial success of the activity, the Company accounts for such arrangement as a collaborative arrangement under ASC 808, Collaborative Arrangements . ASC 808 describes arrangements within its scope and considerations surrounding presentation and disclosure, with recognition matters subjected to other authoritative guidance, in certain cases by analogy. For arrangements determined to be within the scope of ASC 808 where a collaborative partner is not a customer for certain research and development activities, the Company accounts for payments received for the reimbursement of research and development costs as a contra-expense in the period such expenses are incurred. This reflects the joint risk sharing nature of these activities within a collaborative arrangement. The Company classifies payments owed or receivables recorded as other current liabilities or prepaid expenses and other current assets, respectively, in the Company’s consolidated balance sheets. If payments from the collaborative partner to the Company represent consideration from a customer in exchange for distinct goods and services provided, then the Company accounts for those payments within the scope of ASC 606, Revenue from Contracts with Customers (“ASC 606”). Please refer to Note 3, “Collaboration Agreement” for additional details regarding the Company’s Strategic Collaboration Agreement with AstraZeneca UK Limited (“AstraZeneca”) (the “AstraZeneca Agreement”).
Revenue from Contracts with Customers	Revenue from Contracts with Customers In accordance with ASC 606, the Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, it performs the following five steps: (i) identify the 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 within the contract and (v) recognize revenue when (or as) the Company satisfies a performance obligation. The Company only applies the five-step model to contracts when it determines that it is probable it will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within the contract to determine whether each promised good or service is a performance obligation. The promised goods or services in the Company’s arrangements typically consist of a license to the Company’s intellectual property and/or research and development services. The Company may provide customers with options to additional items in such arrangements, which are accounted for separately when the customer elects to exercise such options, unless the option provides a material right to the customer. Performance obligations are promises in a contract to transfer a distinct good or service to the customer that (i) the customer can benefit from on its own or together with other readily available resources, and (ii) is separately identifiable from other promises in the contract. Goods or services that are not individually distinct performance obligations are combined with other promised goods or services until such combined group of promises meet the requirements of a performance obligation. The Company determines transaction price based on the amount of consideration the Company expects to receive for transferring the promised goods or services in the contract. Consideration may be fixed, variable, or a combination of both. At contract inception for arrangements that include variable consideration, the Company estimates the probability and extent of consideration it expects to receive under the contract utilizing either the most likely amount method or expected amount method, whichever best estimates the amount expected to be received. The Company then considers any constraints on the variable consideration and includes in the transaction price variable consideration to the extent it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. The Company then allocates the transaction price to each performance obligation based on the relative standalone selling price and recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) control is transferred to the customer and the performance obligation is satisfied. For performance obligations which consist of licenses and other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The Company records amounts as accounts receivable when the right to consideration is deemed unconditional. Amounts received, or that are unconditionally due, from a customer prior to transferring goods or services to the customer under the terms of a contract are recognized as deferred revenue. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as the current portion of deferred revenue. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion. The Company’s revenue generating arrangements typically include upfront license fees, milestone payments and/or royalties. If a license is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenue from nonrefundable, up-front fees allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from non-refundable, up-front fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. At the inception of an agreement that includes research and development milestone payments, the Company evaluates each milestone to determine when and how much of the milestone to include in the transaction price. The Company first estimates the amount of the milestone payment that the Company could receive using either the expected value or the most likely amount approach. The Company primarily uses the most likely amount approach as this approach is generally most predictive for milestone payments with a binary outcome. Then, the Company considers whether any portion of the estimated amount is subject to the variable consideration constraint (that is, whether it is probable that a significant reversal of cumulative revenue would not occur upon resolution of the uncertainty). The Company updates the estimate of variable consideration included in the transaction price at each reporting date which includes updating the assessment of the likely amount of consideration and the application of the constraint to reflect current facts and circumstances. For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company will recognize revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). For the three and six months ended June 30, 2023 , the Company recorded less than $ 0.1 million and $ 0.1 million, respectively, of revenue under collaboration agreements. For the three and six months ended June 30, 2022 , the Company recorded $ 0.6 million and $ 1.2 million, respectively, of revenue under collaboration agreements. Please refer to Note 3, “Collaboration Agreement” for additional details regarding revenue recognition under the AstraZeneca Agreement.
Business Combinations	Business Combinations In determining whether an acquisition should be accounted for as a business combination or asset acquisition, the Company first determines whether substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets. If this is the case, the single identifiable asset or the group of similar assets is not deemed to be a business, and is instead deemed to be an asset. If this is not the case, the Company then further evaluates whether the single identifiable asset or group of similar identifiable assets and activities includes, at a minimum, an input and a substantive process that together significantly contribute to the ability to create outputs. If so, the Company concludes that the single identifiable asset or group of similar identifiable assets and activities is a business. The Company accounts for business combinations using the acquisition method of accounting. Application of this method of accounting requires that (i) identifiable assets acquired (including identifiable intangible assets) and liabilities assumed generally be measured and recognized at fair value as of the acquisition date and (ii) the excess of the purchase price over the net fair value of identifiable assets acquired and liabilities assumed be recognized as goodwill, which is not amortized for accounting purposes but is subject to testing for impairment at least annually. Acquired in-process research and development (“IPR&D”) is recognized at fair value and initially characterized as an indefinite-lived intangible asset, irrespective of whether the acquired IPR&D has an alternative future use. Transaction costs related to business combinations are expensed as incurred. Determining the fair value of assets acquired and liabilities assumed in a business combination requires management to use significant judgment and estimates, especially with respect to intangible assets. During the measurement period, which extends no later than one year from the acquisition date, the Company may record certain adjustments to the carrying value of the assets acquired and liabilities assumed with the corresponding offset to goodwill. After the measurement period, all adjustments are recorded in the consolidated statements of operations as operating expenses or income. To date, the Company has not recorded any acquisitions as a business combination.
Asset Acquisitions	Asset Acquisitions The Company measures and recognizes asset acquisitions that are not deemed to be business combinations based on the cost to acquire the assets, which includes transaction costs. Goodwill is not recognized in asset acquisitions. In an asset acquisition, the cost allocated to acquire IPR&D with no alternative future use is charged to expense at the acquisition date. Contingent consideration in asset acquisitions payable in the form of cash is recognized when payment becomes probable and reasonably estimable, unless the contingent consideration meets the definition of a derivative, in which case the amount becomes part of the asset acquisition cost when acquired. Contingent consideration payable in the form of a fixed number of the Company’s own shares is measured at fair value as of the acquisition date and recognized when the issuance of the shares becomes probable. Upon recognition of the contingent consideration payment, the amount is included in the cost of the acquired asset or group of assets, or, if related to IPR&D with no alternative future use, charged to expense.
Fair Value Measurements	Fair Value Measurements Certain assets and liabilities of the Company are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable: • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques. The Company’s cash equivalents and investments are carried at fair value, determined according to the fair value hierarchy described above (see Note 4). The carrying values of the Company’s amounts due for Canadian harmonized sales tax, accounts payable and accrued expenses approximate their fair values due to the short-term nature of these liabilities.
Leases	Leases The Company accounts for leases in accordance with ASC 842, Leases . At contract inception, the Company determines if an arrangement is or contains a lease. A lease conveys the right to control the use of an identified asset for a period of time in exchange for consideration. If determined to be or contain a lease, the lease is assessed for classification as either an operating or finance lease at the lease commencement date, defined as the date on which the leased asset is made available for use by the Company, based on the economic characteristics of the lease. For each lease with a term greater than twelve months, the Company records a right-of-use asset and lease liability. A right-of-use asset represents the economic benefit conveyed to the Company by the right to use the underlying asset over the lease term. A lease liability represents the obligation to make lease payments arising from the lease. The Company records amortization of operating right-of-use assets and accretion of lease liabilities as a single lease cost on a straight-line basis over the lease term. The Company elected the practical expedient to not separate lease and non-lease components and therefore measures each lease payment as the total of the fixed lease and associated non-lease components. Lease liabilities are measured at the lease commencement date and calculated as the present value of the future lease payments in the contract using the rate implicit in the contract, when available. If an implicit rate is not readily determinable, the Company uses its incremental borrowing rate measured as the rate at which the Company could borrow, on a fully collateralized basis, a commensurate loan in the same currency over a period consistent with the lease term at the commencement date. Right-of-use assets are measured as the lease liability plus initial direct costs and prepaid lease payments, less lease incentives granted by the lessor. The lease term is measured as the noncancelable period in the contract, adjusted for any options to extend or terminate when it is reasonably certain the Company will extend the lease term via such options based on an assessment of economic factors present as of the lease commencement date. The Company elected the practical expedient to not recognize leases with a lease term of twelve months or less. The Company assesses its right-of-use assets for impairment consistent with the assessment performed for long-lived assets used in operations. If an impairment is recognized on operating lease right-of-use assets, the lease liability continues to be recognized using the same effective interest method as before the impairment and the operating lease right-of-use asset is amortized over the remaining term of the lease on a straight-line basis. The Company’s operating leases are presented in the condensed consolidated balance sheet as operating lease right-of-use assets, classified as noncurrent assets, and operating lease liabilities, classified as current and noncurrent liabilities based on the discounted lease payments to be made within the proceeding twelve months. Variable costs associated with a lease, such as maintenance and utilities, are not included in the measurement of the lease liabilities and right-of-use assets but rather are expensed when the events determining the amount of variable consideration to be paid have occurred.
Research, Development and Manufacturing Contract Costs and Accruals	Research, Development and Manufacturing Contract Costs and Accruals The Company has entered into various research, development and manufacturing contracts with research institutions and other companies. These agreements are generally cancelable, and related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing research, development and manufacturing costs. When billing terms under these contracts do not coincide with the timing of when the work is performed, the Company is required to make estimates of outstanding obligations to those third parties as of period end. Any accrual estimates are based on a number of factors, including the Company’s knowledge of the progress towards completion of the research, development and manufacturing activities, invoicing to date under the contracts, communication from the research institutions and other companies of any actual costs incurred during the period that have not yet been invoiced and the costs included in the contracts. Significant judgments and estimates may be made in determining the accrued balances at the end of any reporting period. Actual results could differ from the estimates made by the Company. The historical accrual estimates made by the Company have not been materially different from the actual costs.
Comprehensive Loss	Comprehensive Loss Comprehensive loss includes net loss as well as other changes in shareholders’ equity that result from transactions and economic events other than those with shareholders. For the three and six months ended June 30, 2023 and 2022 , unrealized gains and losses on investments are included in other comprehensive (loss) income as a component of shareholders’ equity until realized.
Net Loss per Share	Net Loss per Share Basic net income (loss) per share attributable to common shareholders is computed by dividing the net income (loss) attributable to common shareholders by the weighted-average number of common shares outstanding for the period. Diluted net income (loss) attributable to common shareholders is computed by adjusting net income (loss) attributable to common shareholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net income (loss) per share attributable to common shareholders is computed by dividing the diluted net income (loss) attributable to common shareholders by the weighted-average number of common shares outstanding for the period, including potential dilutive common shares. For purposes of this calculation, outstanding stock options, restricted stock units and warrants are considered potential dilutive common shares.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements The Company qualifies as “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 and has elected to “opt in” to the extended transition related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different application dates for public and nonpublic companies, the Company will adopt the new or revised standard at the time nonpublic companies adopt the new or revised standard and will do so until such time that the Company either (i) irrevocably elects to “opt out” of such extended transition period or (ii) no longer qualifies as an emerging growth company. The Company may choose to early adopt any new or revised accounting standards whenever such early adoption is permitted for private companies. In June 2016, the FASB issued ASU 2016-13 which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available-for-sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. These changes will result in earlier recognition of credit losses. In November 2018, the FASB issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments—Credit Losses , which narrowed the scope and changed the effective date for non-public entities for ASU 2016-13. The FASB subsequently issued supplemental guidance within ASU No. 2019-05, Financial Instruments—Credit Losses (Topic 326): Targeted Transition Relief (“ASU 2019-05”). ASU 2019-05 provides an option to irrevocably elect the fair value option for certain financial assets previously measured at amortized cost basis. This guidance is effective for the Company for annual periods beginning after December 15, 2022, including interim periods within that fiscal year. The Company adopted ASU 2016-13 effective January 1, 2023, and the adoption did not have a material impact on its condensed consolidated financial statements.

Collaboration Agreement (Tables

Collaboration Agreement (Tables)	6 Months Ended
	Jun. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Changes in the Contract Assets and Liabilities	The following table presents changes in the Company’s accounts receivable and contract liabilities for the six months ended June 30, 2023 (in thousands): Balance as of Balance as of December 31, 2022 Additions Deductions June 30, 2023 Accounts receivable $ 61 $ 62 $ ( 61 ) $ 62 Contract liabilities: Deferred revenue $ 3,000 $ — $ — $ 3,000
Schedule of Revenue Recognized	During the three and six months ended June 30, 2023 and 2022, the Company recognized the following revenue (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Revenue recognized in the period from: Amounts included in deferred revenue at the beginning of the period $ — $ 393 $ — $ 831

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2023
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following tables present information about the Company’s financial assets and liabilities that are measured at fair value on a recurring basis and indicates the level of the fair value hierarchy used to determine such fair values (in thousands): Fair Value Measurements as of Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 8,361 $ — $ — $ 8,361 Canadian Government agency debt securities — 4,425 — 4,425 Investments: Commercial paper — 27,844 — 27,844 Corporate bonds — 15,136 — 15,136 Canadian Government agency debt securities — 15,070 — 15,070 U.S. Government agency debt securities — 136,447 — 136,447 $ 8,361 $ 198,922 $ — $ 207,283 Fair Value Measurements as of Level 1 Level 2 Level 3 Total Assets: Cash equivalents: Money market funds $ 4,241 $ — $ — $ 4,241 U.S. Government agency debt securities — 5,974 — 5,974 Investments: Commercial paper — 28,792 — 28,792 Corporate bonds — 14,342 — 14,342 Municipal bonds — 2,697 — 2,697 Canadian Government agency debt securities — 19,911 — 19,911 U.S. Government agency debt securities — 77,032 — 77,032 $ 4,241 $ 148,748 $ — $ 152,989

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2023
Investments, Debt and Equity Securities [Abstract]
Schedule of Investments	Investments consisted of the following (in thousands): June 30, 2023 Amortized Cost Fair Value Due within one year or less $ 166,096 $ 166,074 Due after one year through three years 28,653 28,423 $ 194,749 $ 194,497 December 31, 2022 Amortized Cost Fair Value Due within one year or less $ 127,441 $ 127,013 Due after one year through three years 15,802 15,761 $ 143,243 $ 142,774
Amortized Cost and Estimated Fair Value of Investments by Contractual Maturity	As of June 30, 2023, the amortized cost and estimated fair value of investments, by contractual maturity, was as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Current Non-Current Commercial paper $ 27,870 $ 1 $ ( 27 ) $ 27,844 $ 27,844 $ — Corporate bonds 15,229 3 ( 96 ) 15,136 7,885 7,251 Canadian Government agency debt securities 14,777 301 ( 8 ) 15,070 15,070 — U.S. Government agency debt securities 136,873 5 ( 431 ) 136,447 115,275 21,172 $ 194,749 $ 310 $ ( 562 ) $ 194,497 $ 166,074 $ 28,423 As of December 31, 2022, the amortized cost and estimated fair value of investments, by contractual maturity, was as follows (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Current Non-Current Commercial paper $ 28,804 $ 10 $ ( 22 ) $ 28,792 $ 28,792 $ — Corporate bonds 14,354 4 ( 16 ) 14,342 9,469 4,873 Municipal bonds 2,705 — ( 8 ) 2,697 2,697 — Canadian Government agency debt securities 20,065 23 ( 177 ) 19,911 19,911 — U.S. Government agency debt securities 77,315 15 ( 298 ) 77,032 66,144 10,888 $ 143,243 $ 52 $ ( 521 ) $ 142,774 $ 127,013 $ 15,761

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	6 Months Ended
	Jun. 30, 2023
Prepaid Expense and Other Assets, Current [Abstract]
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): June 30, 2023 December 31, 2022 Prepaid external research and development expenses $ 4,646 $ 3,741 Prepaid insurance — 1,295 Prepaid software subscriptions 602 402 Income tax receivable 269 386 Interest receivable 688 332 Other receivable due from AstraZeneca 1,053 352 Canadian harmonized sales tax receivable 330 592 Other 1,695 509 $ 9,283 $ 7,609

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2023
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following (in thousands): June 30, 2023 December 31, 2022 Accrued employee compensation and benefits $ 3,469 $ 4,140 Accrued external research and development expenses 4,139 4,914 Accrued professional and consulting fees 1,135 916 Unearned grant income 436 591 Other 164 44 $ 9,343 $ 10,605

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2023
Debt Disclosure [Abstract]
Summary of Long-term Debt, Net of Discount	Long-term debt, net of discount, consisted of the following (in thousands): June 30, 2023 Principal amount of long‑term debt $ 35,000 Less: Current portion of long‑term debt — Long‑term debt, net of current portion 35,000 Accretion of Final Fee 273 Debt discount ( 781 ) Long‑term debt, net of discount $ 34,492
Summary of Estimated Future Principal Payments Due	As of June 30, 2023, the estimated future principal payments due were as follows (in thousands): Year Ending December 31, 2023 (six months) $ — 2024 — 2025 10,652 2026 18,261 2027 6,087 $ 35,000

Share-Based Compensation (Table

Share-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2023
Share-Based Payment Arrangement [Abstract]
Fair Value of Options Estimated on Date of Grant Using Black-Scholes Option Pricing Model	The following table presents, on a weighted-average basis, the assumptions used in the Black-Scholes option-pricing model to determine the grant-date fair value of stock options granted: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Risk-free interest rate 3.69 % 3.27 % 3.83 % 1.79 % Expected term (in years) 5.9 5.8 6.0 5.7 Expected volatility 66.6 % 67.8 % 65.4 % 62.4 % Expected dividend yield 0 % 0 % 0 % 0 %
Summary of Stock Option Activity	The following table summarizes the Company’s stock option activity since December 31, 2022: Number of Weighted- Weighted- Aggregate (in years) (in thousands) Outstanding as of December 31, 2022 10,531,555 $ 7.08 7.5 $ 4,434 Granted 4,315,000 3.76 Exercised ( 3,221 ) 3.55 Forfeited/cancelled ( 684,341 ) 7.15 Outstanding as of June 30, 2023 14,158,993 $ 6.06 7.9 $ 14,399 Vested and expected to vest as of June 30, 2023 14,067,927 $ 6.03 7.9 $ 14,399 Options exercisable as of June 30, 2023 6,378,773 $ 6.69 6.6 $ 8,210
Summary of Restricted Stock Unit Activity	The following table summarizes the Company’s restricted stock unit activity since December 31, 2022: Number of Weighted- Unvested as of December 31, 2022 65,500 $ 5.91 Granted — — Vested — — Forfeited — — Unvested as of June 30, 2023 65,500 $ 5.91
Summary of Stock Based Compensation Expense	Share-based compensation expense was classified in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Research and development expenses $ 1,111 $ 933 $ 2,249 $ 1,818 General and administrative expenses 1,935 1,803 3,946 3,551 $ 3,046 $ 2,736 $ 6,195 $ 5,369

Net Loss per Share (Tables)

Net Loss per Share (Tables)	6 Months Ended
	Jun. 30, 2023
Earnings Per Share [Abstract]
Basic and Diluted Net Loss per Share	Basic and diluted net loss per share attributable to common shareholders was calculated as follows (in thousands, except share and per share amounts): Three Months Ended Six Months Ended 2023 2022 2023 2022 Numerator: Net loss $ ( 25,175 ) $ ( 19,073 ) $ ( 49,466 ) $ ( 38,982 ) Denominator: Weighted-average common shares outstanding—basic and diluted 66,277,279 43,357,240 60,061,166 43,264,175 Net loss per share attributable to common shareholders —basic $ ( 0.38 ) $ ( 0.44 ) $ ( 0.82 ) $ ( 0.90 )
Summary of Potential Common Shares Excluded from Calculation of Diluted Net Loss per Share	The Company’s potentially dilutive securities, which include stock options and common share warrants, have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted-average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common shareholders is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common shareholders for the periods indicated because including them would have had an anti-dilutive effect: Six Months Ended 2023 2022 Options to purchase common shares 14,158,993 9,924,748 Unvested restricted stock units 65,500 73,700 Warrants to purchase common shares 196,120 26,110 14,420,613 10,024,558

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2023
Leases [Abstract]
Component of Operating Lease Cost	The components of operating lease cost, which are included within operating expenses in the accompanying condensed consolidated statements of operations and comprehensive loss, are as follows (in thousands): Three Months Ended Six Months Ended 2023 2022 2023 2022 Operating lease cost $ 994 $ 369 $ 1,490 $ 735 Variable lease cost 127 27 149 40 Total lease cost $ 1,121 $ 396 $ 1,639 $ 775
Summary of Supplemental Information of Operating Lease	The following table summarizes supplemental information for the Company’s operating leases: As of June 30, 2023 Weighted-average remaining lease term (in years) 10.2 Weighted average discount rate 11.0 % Cash paid for amounts included in the measurement of lease liabilities (in thousands) $ 1,009
Summary of Future Maturities of Operating Lease Liabilities	As of June 30, 2023, the future maturities of operating lease liabilities are as follows (in thousands): Year Ending December 31, 2023 (six months) $ 3,934 2024 3,135 2025 2,598 2026 2,357 2027 1,341 Thereafter 13,688 Total lease payments $ 27,053 Less: imputed interest ( 10,923 ) Total lease liabilities $ 16,130

Related Party Transactions (Tab

Related Party Transactions (Tables)	6 Months Ended
	Jun. 30, 2023
Related Party Transactions [Abstract]
Schedule of Recognized Expenses in Connection with Services Performed Under Master Services Agreement and Supply Agreement	The Company recognized expenses in connection with the services performed in the normal course of business under the Master Services Agreement and the Supply Agreement in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands): Three Months Ended Six Months Ended 2022 2022 Research and development expenses $ 418 $ 1,408 General and administrative expenses 3 17 $ 421 $ 1,425

Geographical Information (Table

Geographical Information (Tables)	6 Months Ended
	Jun. 30, 2023
Geographic Areas, Long-Lived Assets [Abstract]
Schedule of Long-lived Assets by Geographic Areas	The Company has operating companies in the United States and Canada. Information about the Company’s long-lived assets, consisting solely of property and equipment, net, by geographic region was as follows (in thousands): June 30, December 31, United States $ 405 $ 465 Canada 5,304 4,166 $ 5,709 $ 4,631

Nature of the Business and Ba_2

Nature of the Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Formation and incorporation date					Dec. 31, 2014
Net loss	$ 25,175	$ 24,291	$ 19,073	$ 19,909	$ 49,466	$ 38,982
Accumulated deficit	$ 331,328				$ 331,328		$ 281,862

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Oct. 31, 2019
Summary Of Significant Accounting Policies [Line Items]
Foreign currency transaction (losses) gains	$ 100,000	$ (600,000)	$ (300,000)	$ (300,000)
Restricted cash, current	419,000		419,000		$ 454,000
Letters of credit	1,000,000		1,000,000			$ 1,500,000
Restricted cash	849,000		849,000		1,018,000
Cash, cash equivalents and restricted cash	33,300,000		33,300,000		45,300,000
Cash and cash equivalents	32,000,000		32,000,000		43,900,000
Restricted Cash	1,300,000		1,300,000		1,500,000
Deferred offering costs	100,000		100,000		200,000
Astra Zeneca U K Limited [Member] | Strategic Collaboration Agreement [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Revenue under collaboration agreement	100,000	$ 600,000	100,000	$ 1,200,000
Collateralized Securities [Member]
Summary Of Significant Accounting Policies [Line Items]
Restricted cash, current	200,000		200,000		200,000
Restricted cash	800,000		800,000		1,000,000
Collateralize Credit Cards [Member]
Summary Of Significant Accounting Policies [Line Items]
Restricted cash, current	200,000		200,000		200,000
Guaranteed Investment Certificate [Member]
Summary Of Significant Accounting Policies [Line Items]
Restricted cash, current	$ 100,000		$ 100,000		$ 100,000

Collaboration Agreement - Addit

Collaboration Agreement - Additional Information (Detail)	1 Months Ended	3 Months Ended		6 Months Ended
	Oct. 31, 2020 USD ($) Collaboration	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development expense		$ 18,994,000	$ 12,076,000	$ 34,871,000	$ 24,737,000
Prepaid expenses and other current assets		9,283,000		9,283,000		$ 7,609,000
Deferred revenue		333,000		333,000		333,000
Deferred revenue, non-current		2,667,000		2,667,000		2,667,000
AstraZeneca UK Limited [Member] | Strategic Collaboration Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Maximum amount for milestones payments to other party	$ 145,000,000
Upfront payment received				5,000,000
Maximum amount of payments to be received for development milestones				40,000,000
Deferred revenue		300,000		300,000
Deferred revenue, non-current		2,700,000		2,700,000
AstraZeneca UK Limited [Member] | Strategic Collaboration Agreement [Member] | Novel TATs And Combination Therapies [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of collaborative areas | Collaboration	2
AstraZeneca UK Limited [Member] | Novel TATs Collaboration [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development expense		900,000	2,600,000	2,700,000	3,300,000
Research and development expense offset		500,000	$ 1,200,000	1,100,000	$ 1,600,000
Prepaid expenses and other current assets		$ 1,100,000		$ 1,100,000		$ 400,000

Collaboration Agreement - Sched

Collaboration Agreement - Schedule of Changes in the Contract Assets and Liabilities (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2023 USD ($)
Contract assets:
Beginning balance	$ 61
Additions	62
Deductions	(61)
Ending balance	62
Contract liabilities:
Beginning balance	3,000
Ending balance	$ 3,000

Collaboration Agreement - Sch_2

Collaboration Agreement - Schedule of Revenue Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2022
Contract with Customer, Contract Asset, Contract Liability, and Receivable [Abstract]
Amounts included in deferred revenue at the beginning of the period	$ 393	$ 831

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Investments
Investments	$ 207,283	$ 152,989
Corporate Bond Securities [Member]
Investments
Investments	15,136	14,342
Municipal Bonds [Member]
Investments
Investments		2,697
Money Market Funds [Member]
Cash equivalents
Cash equivalents	8,361	4,241
Commercial Paper [Member]
Investments
Investments	27,844	28,792
Canadian Government Agency Debt Securities [Member]
Cash equivalents
Cash equivalents	4,425
Investments
Investments	15,070	19,911
U.S. Government Agency Debt Securities [Member]
Cash equivalents
Cash equivalents		5,974
Investments
Investments	136,447	77,032
Level 1
Investments
Investments	8,361	4,241
Level 1 | Money Market Funds [Member]
Cash equivalents
Cash equivalents	8,361	4,241
Level 2
Investments
Investments	198,922	148,748
Level 2 | Corporate Bond Securities [Member]
Investments
Investments	15,136	14,342
Level 2 | Municipal Bonds [Member]
Investments
Investments		2,697
Level 2 | Commercial Paper [Member]
Investments
Investments	27,844	28,792
Level 2 | Canadian Government Agency Debt Securities [Member]
Cash equivalents
Cash equivalents	4,425
Investments
Investments	15,070	19,911
Level 2 | U.S. Government Agency Debt Securities [Member]
Cash equivalents
Cash equivalents		5,974
Investments
Investments	$ 136,447	$ 77,032

Investments - Schedule of Inves

Investments - Schedule of Investments (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Available-for-sale securities, debt maturities, amortized cost [Abstract]
Amortized Cost, Due within one year or less	$ 166,096	$ 127,441
Amortized Cost, Due after one year through three years	28,653	15,802
Amortized Cost, Investments	194,749	143,243
Available-for-sale securities, debt maturities, Fair Value [Abstract]
Fair Value, Due within one year or less	166,074	127,013
Fair Value, Due after one year through three years	28,423	15,761
Fair value, Investments	$ 194,497	$ 142,774

Investments - Amortized Cost an

Investments - Amortized Cost and Estimated Fair Value of Investments by Contractual Maturity (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Investments, Amortized Cost	$ 194,749	$ 143,243
Available-for-sale Investments, Gross Unrealized Gains	310	52
Available-for-sale Investments, Gross Unrealized Losses	(562)	(521)
Available-for-sale Investments, Fair Value	194,497	142,774
Available-for-sale Investments, Current	166,074	127,013
Available-for-sale Investments, Non Current	28,423	15,761
Commercial Paper [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Investments, Amortized Cost	27,870	28,804
Available-for-sale Investments, Gross Unrealized Gains	1	10
Available-for-sale Investments, Gross Unrealized Losses	(27)	(22)
Available-for-sale Investments, Fair Value	27,844	28,792
Available-for-sale Investments, Current	27,844	28,792
Corporate Bond Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Investments, Amortized Cost	15,229	14,354
Available-for-sale Investments, Gross Unrealized Gains	3	4
Available-for-sale Investments, Gross Unrealized Losses	(96)	(16)
Available-for-sale Investments, Fair Value	15,136	14,342
Available-for-sale Investments, Current	7,885	9,469
Available-for-sale Investments, Non Current	7,251	4,873
Municipal Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Investments, Amortized Cost		2,705
Available-for-sale Investments, Gross Unrealized Losses		(8)
Available-for-sale Investments, Fair Value		2,697
Available-for-sale Investments, Current		2,697
Canadian Government Agency Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Investments, Amortized Cost	14,777	20,065
Available-for-sale Investments, Gross Unrealized Gains	301	23
Available-for-sale Investments, Gross Unrealized Losses	(8)	(177)
Available-for-sale Investments, Fair Value	15,070	19,911
Available-for-sale Investments, Current	15,070	19,911
U.S. Government Agency Debt Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Investments, Amortized Cost	136,873	77,315
Available-for-sale Investments, Gross Unrealized Gains	5	15
Available-for-sale Investments, Gross Unrealized Losses	(431)	(298)
Available-for-sale Investments, Fair Value	136,447	77,032
Available-for-sale Investments, Current	115,275	66,144
Available-for-sale Investments, Non Current	$ 21,172	$ 10,888

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets - Schedule of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid external research and development expenses	$ 4,646	$ 3,741
Prepaid insurance		1,295
Prepaid software subscriptions	602	402
Income tax receivable	269	386
Interest receivable	688	332
Other receivable due from AstraZeneca	1,053	352
Canadian harmonized sales tax receivable	330	592
Other	1,695	509
Prepaid expenses and other current assets	$ 9,283	$ 7,609

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued employee compensation and benefits	$ 3,469	$ 4,140
Accrued external research and development expenses	4,139	4,914
Accrued professional and consulting fees	1,135	916
Unearned grant income	436	591
Other	164	44
Accrued expenses	$ 9,343	$ 10,605

Debt - Summary of Long-term Deb

Debt - Summary of Long-term Debt, Net of Discount (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Debt Disclosure [Abstract]
Principal amount of long-term debt	$ 35,000
Long-term debt, net of current portion	35,000
Accretion of Final Fee	273
Debt discount	(781)
Long-term debt, net of discount	$ 34,492	$ 34,233

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)	Sep. 21, 2022	Apr. 04, 2022	Jan. 31, 2020
Debt Instrument [Line Items]
Number of shares issuable upon exercise of outstanding warrants (in shares)			749,197
Weighted-average exercise price per share (in dollars per share)			$ 8.10
Term Loans [Member] | Loan Agreement [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Term loan facilities bear interest rate	7.90%	7.90%
Debt instrument, description of bear interest rate	The floating per annum rate of interest for borrowings under all four loan facilities was amended to the greater of (i) 8.00% and (ii) the sum of (a) 1-Month CME Term SOFR (as defined in the Second Amendment), (b) 0.10% and (c) 7.90%.Additionally, on March 30, 2023, the Company and the Lender entered into a Third Amendment to Loan and Security Agreement (together with the Loan Agreement, Consent and First Amendment to Loan and Security Agreement, and Second Amendment, the “Amended Loan Agreement”) to amend the availability of the Term C loan facility which is to be funded at the request of the Company, subject to certain conditions being met, no later than March 31, 2024, under the Amended Loan Agreement. As the terms of the amendments were not substantially different than the terms of the Loan Agreement, the amendments were accounted for as a debt modification. Issuance costs paid to the Lender in connection with the amendments were recorded as an additional debt discount and will be amortized to interest expense over the remaining term, together with unamortized original issuance costs, using the effective interest method.	borrowings under all three loan facilities bear interest at a floating per annum rate equal to the greater of (i) 8.00% and (ii) the sum of (a) the greater of (x) 1 Month LIBOR Rate and (y) 0.10% plus (b) 7.90%.
Obligated to pay final fee equal to percentage of aggregate amount of term loan funded		4%
Debt instrument, description of bear interest rate		The Company is obligated to pay a fee equal to 4.00% of the aggregate amount of the term loans funded (the “Final Fee”), to occur upon the earliest of (i) the maturity date, (ii) the acceleration of the term loans, and (iii) the prepayment of the term loans. The Company accretes the Final Fee that will be due at final repayment to outstanding debt by charges to interest expense over the term of the loans using the effective-interest method.The Company has the option to prepay all, but not less than all, of the outstanding principal balance of the term loans under the Loan Agreement. If the Company prepays all or a portion of the term loans prior to the maturity date, it is obligated to pay the Lender a prepayment fee based on a percentage of the outstanding principal balance of the loans, equal to 3.00% if the payment occurs on or before 12 months after the funding date of the applicable loan, 2.00% if the prepayment occurs more than 12 months after, but on or before 24 months after, the funding date of the applicable loan, or 1.00% if the prepayment occurs more than 24 months after, but on or before 36 months after, the funding date of the applicable loan, and no prepayment fee is required thereafter.
Default interest rate		5%
Loan covenant, minimum cash balances required		55%
Loan covenant, minimum cash balances required where cash balance accounts are not maintained		110%
Term Loans [Member] | Loan Agreement [Member] | Oxford Finance LLC [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Term loan facilities bear interest rate		0.10%
Term Loans [Member] | Loan Agreement [Member] | Oxford Finance LLC [Member] | SOFR [Member]
Debt Instrument [Line Items]
Term loan facilities bear interest rate	0.10%
Term Loans [Member] | Loan Agreement [Member] | Oxford Finance LLC [Member] | Maximum [Member]
Debt Instrument [Line Items]
Term loans aggregate principal amount		$ 75,000,000
Term Loans [Member] | Loan Agreement [Member] | Oxford Finance LLC [Member] | Minimum [Member] | Floating per Annum Rate [Member]
Debt Instrument [Line Items]
Term loan facilities bear interest rate	8%	8%
Term A and B Loan Facility [Member] | Loan Agreement [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date		Apr. 01, 2027
Term A B And C Loan Facility [Member] | Loan Agreement [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Term loan commitment amount		$ 75,000,000
Term A B C And D Loan Facility [Member] | Loan Agreement [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Term loan commitment amount	$ 75,000,000
Term A Loan Facility [Member] | Loan Agreement [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Term loan commitment amount		$ 25,000,000
Number of shares issuable upon exercise of outstanding warrants (in shares)		26,110
Weighted-average exercise price per share (in dollars per share)		$ 7.66
Warrants equal to percentage of initial amount funded		2%
Debt discount		$ 100,000
Term A Loan Facility [Member] | Loan Agreement [Member] | Funded on Closing Date [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Term loan commitment amount	10,000,000	10,000,000
Term A Loan Facility [Member] | Loan Agreement [Member] | Funded, One-time Basis at Any Time Prior to April 4, 2023 [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Term loan commitment amount		$ 15,000,000
Term B Loan Facility [Member] | Loan Agreement [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Term loan commitment amount	25,000,000
Number of shares issuable upon exercise of outstanding warrants (in shares)		170,010
Weighted-average exercise price per share (in dollars per share)		$ 2.94
Warrants equal to percentage of initial amount funded		2%
Additional warrants equal to percentage of loan funded		25%
Debt discount		$ 400,000
Term B Loan Facility [Member] | Loan Agreement [Member] | Funded, Subject to Certain Conditions Being Met, No Later Than June 30, 2023 [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Term loan commitment amount		$ 25,000,000
Term C Loan Facility [Member] | Loan Agreement [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Additional warrants equal to percentage of loan funded		2%
Warrant termination period		10 years
Term C Loan Facility [Member] | Loan Agreement [Member] | Funded, One-time Basis at Any Time Prior to April 4, 2023 [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Term loan commitment amount	15,000,000
Term C Loan Facility [Member] | Loan Agreement [Member] | Funded at Lender's Sole Discretion [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Term loan commitment amount		$ 25,000,000
Term D Loan Facility [Member] | Loan Agreement [Member] | Funded at Lender's Sole Discretion [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Term loan commitment amount	$ 25,000,000

Debt - Summary of Estimated Fut

Debt - Summary of Estimated Future Principal Payments Due (Detail) $ in Thousands	Jun. 30, 2023 USD ($)
Debt Disclosure [Abstract]
2025	$ 10,652
2026	18,261
2027	6,087
Total	$ 35,000

Equity - Additional Information

Equity - Additional Information (Detail) - USD ($)			1 Months Ended			6 Months Ended
	May 10, 2023	Feb. 13, 2023	Jan. 31, 2022	Jul. 31, 2021	Jan. 31, 2020	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Apr. 30, 2022
Class Of Stock [Line Items]
Number of shares agreed to sell						68,990,263	44,805,627
Common stock, no par value						$ 0	$ 0
Common stock, voting rights description						Each common share entitles the holder to one vote on all matters submitted to a vote of the Company’s shareholders.
Cash dividends						$ 0
Number of shares issuable upon exercise of outstanding warrants (in shares)					749,197
Weighted-average exercise price per share (in dollars per share)					$ 8.10
Expiration period					2 years
Warrant
Class Of Stock [Line Items]
Unexercised common share warrants expired			651,816
Class B Convertible Preferred Shares [Member]
Class Of Stock [Line Items]
Number of shares issuable upon exercise of outstanding warrants (in shares)					3,126,391
Weighted-average exercise price per share (in dollars per share)					$ 1.5154
Class B Preferred Exchangable Shares [Member]
Class Of Stock [Line Items]
Number of shares issuable upon exercise of outstanding warrants (in shares)					873,609
Weighted-average exercise price per share (in dollars per share)					$ 1.5154
May 2023 Purchase Agreement [Member]
Class Of Stock [Line Items]
Number of shares agreed to sell	4,784,689
Purchase price per share	$ 4.18
Net proceeds of common shares	$ 20,000,000
Common stock, no par value	$ 0
February 2023 Purchase Agreement [Member]
Class Of Stock [Line Items]
Number of shares agreed to sell		17,648,596
Purchase price per share		$ 3.4
Net proceeds of common shares		$ 56,000,000
Common stock, no par value		$ 0
Open Market Sales Agreement [Member]
Class Of Stock [Line Items]
Net proceeds of common shares						$ 13,600,000
Number of common shares issued and sold						3,211,011
Open Market Sales Agreement [Member] | Maximum [Member]
Class Of Stock [Line Items]
Net proceeds of common shares				$ 100,000,000
Compensation percentage of gross proceeds				3%
Loan Agreement with Oxford Finance LLC
Class Of Stock [Line Items]
Number of shares issuable upon exercise of outstanding warrants (in shares)								170,010	26,110
Weighted-average exercise price per share (in dollars per share)								$ 2.94	$ 7.66
Percentage of initial funding								2%	2%
Initial funded amount								$ 25,000,000	$ 10,000,000
Common share warrants outstanding						196,120

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Jun. 18, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average grant-date fair value of stock options granted	$ 2.35	$ 4.33
Aggregate unrecognized share-based compensation expense	$ 24,700,000
Unrecognized share-based compensation expense, weighted average period expects for recognition	2 years 10 months 24 days
Number of shares exercised	3,221
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Intrinsic value for stock options exercised	$ 100,000	$ 300,000
Outside Stock Option Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options, granted	2,726,850
Restricted Stock Units R S U [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate unrecognized share-based compensation expense	$ 300,000
Unrecognized share-based compensation expense, weighted average period expects for recognition	1 year 9 months 18 days
2020 Stock Option and incentive plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock reserved for future issuance	10,073,496			4,273,350
Stock incentive plan description	cumulatively increased each January 1 by 4% of the number of the Company’s common shares outstanding on the immediately preceding December 31 or such lesser number of shares determined by the Company’s compensation committee of the board of directors
Annual percentage increase in common stock reserved for future issuance	4%
Number of shares remained available for future grant	1,436,819
2017 Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock reserved for future issuance	0		0
Number of shares remained available for future grant	0		0
2020 Employee Share Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock reserved for future issuance	1,746,220			450,169
Stock incentive plan description	the number of common shares that may be issued under the ESPP is automatically increased each January 1 by the lesser of (i) 900,338 common shares, (ii) 1% of the number of the Company’s common shares outstanding on the immediately preceding December 31 and (iii) such lesser number of shares as determined by the Company’s compensation committee of the board of directors.
Annual percentage increase in common stock reserved for future issuance	1%
Maximum annual increase in common stock reserved for future issuance	900,338
Shares, issued	43,857
Performance Based Vesting [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate unrecognized share-based compensation expense	$ 700,000

Share-Based Compensation - Fair

Share-Based Compensation - Fair Value of Options Estimated on Date of Grant Using Black-Scholes Option Pricing Model (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Share-Based Payment Arrangement [Abstract]
Risk-free interest rate	3.69%	3.27%	3.83%	1.79%
Expected term (in years)	5 years 10 months 24 days	5 years 9 months 18 days	6 years	5 years 8 months 12 days
Expected volatility	66.60%	67.80%	65.40%	62.40%
Expected dividend yield	0%	0%	0%	0%

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Stock Option Activity (Detail) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares
Share-Based Payment Arrangement [Abstract]
Number of Shares, Beginning balance | shares	10,531,555
Number of Shares, Granted | shares	4,315,000
Number of Shares, Exercised | shares	(3,221)
Number of Shares, Forfeited/cancelled | shares	(684,341)
Number of Shares, Ending balance | shares	14,158,993	10,531,555
Number of Shares, Options vested and expected to vest | shares	14,067,927
Number of Shares, Options exercisable | shares	6,378,773
Weighted Average Exercise Price, Beginning balance | $ / shares	$ 7.08
Weighted Average Exercise Price, Granted | $ / shares	3.76
Weighted Average Exercise Price, Exercised | $ / shares	3.55
Weighted Average Exercise Price, Forfeited/cancelled | $ / shares	7.15
Weighted Average Exercise Price, Ending balance | $ / shares	6.06	$ 7.08
Weighted Average Exercise Price, Options vested and expected to vest | $ / shares	6.03
Weighted Average Exercise Price, Options exercisable | $ / shares	$ 6.69
Weighted-Average Remaining Contractual Term, Outstanding	7 years 10 months 24 days	7 years 6 months
Weighted Average Remaining Contractual Term, Options vested and expected to vest	7 years 10 months 24 days
Weighted Average Remaining Contractual Term, Options exercisable	6 years 7 months 6 days
Aggregate Intrinsic Value | $	$ 14,399	$ 4,434
Aggregate Intrinsic Value, Options vested and expected to vest | $	14,399
Aggregate Intrinsic Value, Options exercisable | $	$ 8,210

Share-Based Compensation - Su_2

Share-Based Compensation - Summary of Restricted Stock Unit Activity (Detail)	Jun. 30, 2023 $ / shares shares
Share-Based Payment Arrangement [Abstract]
Number of Shares, Beginning balance | shares	65,500
Number of Shares, Ending balance | shares	65,500
Weighted - Average Grant Date Fair Value, Beginning balance | $ / shares	$ 5.91
Weighted - Average Grant Date Fair Value, Ending balance | $ / shares	$ 5.91

Share-Based Compensation - Su_3

Share-Based Compensation - Summary of Stock Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 3,046	$ 2,736	$ 6,195	$ 5,369
Research and Development Expense [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	1,111	933	2,249	1,818
General and Administrative Expense [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 1,935	$ 1,803	$ 3,946	$ 3,551

License Agreements and Asset _2

License Agreements and Asset Acquisitions - Additional Information (Detail) € in Millions			1 Months Ended	3 Months Ended				6 Months Ended		12 Months Ended
	Feb. 10, 2023 USD ($)	Aug. 12, 2021 CAD ($)	Aug. 31, 2022 USD ($) shares	Jun. 30, 2023 USD ($) shares	Jun. 30, 2022 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2021 EUR (€) shares	Jun. 30, 2023 USD ($) shares	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2023 CAD ($) shares	Jun. 09, 2022 USD ($)
Research And Development Arrangement Contract To Perform For Others [Line Items]
Research and development				$ 18,994,000	$ 12,076,000			$ 34,871,000	$ 24,737,000
Assets held				$ 268,286,000				$ 268,286,000		$ 219,064,000
Common stock, shares issued | shares				68,990,263				68,990,263		44,805,627			68,990,263
RadioMedix Agreement [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Option fee										$ 800,000
Option exercise fee	$ 1,500,000
RadioMedix Agreement [Member] | Maximum [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Additional amount to be paid on net sales	50,000,000
Additional amount to be paid upon achievement of clinical and regulatory milestones	10,500,000
Increase in regulatory milestone payments	$ 4,000,000
RadioMedix Agreement [Member] | Research and Development Expense [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Option exercise fee								$ 1,500,000
CPDC [Member] | Research and License Agreement [Member] | Research and Development Expense [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Milestone payment				$ 0	0			0	0
ImmunoGen [Member] | Research and License Agreement [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Upfront license fee paid								200,000
ImmunoGen [Member] | Research and License Agreement [Member] | Maximum [Member] | Development And Regulatory Milestone [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Performance milestone payments based on successful development				15,000,000				15,000,000
ImmunoGen [Member] | Research and License Agreement [Member] | Maximum [Member] | Sales Based Milestone [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Performance milestone payments based on successful development				35,000,000				35,000,000
ImmunoGen [Member] | Research and License Agreement [Member] | Research and Development Expense [Member] | Development And Regulatory Milestone [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Upfront license fee paid				0	0			0	0
Rainier Therapeutics, Inc. [Member] | Asset Acquisition and License Agreement [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Additional amount payable under agreement				$ 3,500,000				$ 3,500,000
Non-voting common stock, issued | shares				313,359				313,359					313,359
Rainier Therapeutics, Inc. [Member] | Asset Acquisition and License Agreement [Member] | Development And Regulatory Milestone [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Performance milestone payments based on successful development				$ 22,500,000				$ 22,500,000
Non-voting common stock, issued | shares				156,679				156,679					156,679
Rainier Therapeutics, Inc. [Member] | Asset Acquisition and License Agreement [Member] | Sales Based Milestone [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Performance milestone payments based on successful development				$ 42,000,000				$ 42,000,000
Rainier Therapeutics, Inc. [Member] | Asset Acquisition and License Agreement [Member] | Phase1
Research And Development Arrangement Contract To Perform For Others [Line Items]
Milestone payment			$ 2,000,000
Common stock, shares issued | shares			156,679
Rainier Therapeutics, Inc. [Member] | Asset Acquisition and License Agreement [Member] | Maximum [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Potential future payment as percentage of amount the Company receives under sublicense agreements				30%				30%					30%
Rainier Therapeutics, Inc. [Member] | Asset Acquisition and License Agreement [Member] | Minimum [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Potential future payment as percentage of amount the Company receives under sublicense agreements				10%				10%					10%
Rainier Therapeutics, Inc. [Member] | Asset Acquisition and License Agreement [Member] | Research and Development Expense [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Upfront license fee paid												$ 1,000,000
Research and development				$ 0	0			$ 0	0
Additional amount payable under agreement											$ 3,500,000
Genentech, Inc. [Member] | Asset Acquisition and License Agreement [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Research and development				0	0			0	0
Genentech, Inc. [Member] | Asset Acquisition and License Agreement [Member] | Maximum [Member] | Sales Based Milestone [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Performance milestone payments based on successful development				44,000,000				44,000,000
TRIUMF Innovations Inc. [Member] | Asset Acquisition and License Agreement [Member] | Accounts Payable [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Total milestone payment achieved				2,300,000				2,300,000					$ 3,000,000
TRIUMF Innovations Inc. [Member] | Asset Acquisition and License Agreement [Member] | Development And Regulatory Milestone [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Performance milestone payments based on successful development													5,000,000
TRIUMF Innovations Inc. [Member] | Asset Acquisition and License Agreement [Member] | Maximum [Member] | Actinium-225 [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Performance milestone payments based on successful development		$ 15,000,000
TRIUMF Innovations Inc. [Member] | Asset Acquisition and License Agreement [Member] | Minimum [Member] | Actinium-225 [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Percentage of annual requirements		50%
TRIUMF Innovations Inc. [Member] | Asset Acquisition and License Agreement [Member] | Research and Development Expense [Member] | Maximum [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Amortization expenses				100,000	100,000			100,000	100,000
TRIUMF Innovations Inc. [Member] | Amended Collaboration Agreement [Member] | Accounts Payable [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Total milestone payment achieved				6,600,000				6,600,000					$ 8,500,000
Milestone payment paid										2,600,000	$ 3,900,000
TRIUMF Innovations Inc. [Member] | Amended Collaboration Agreement [Member] | Research and Development Expense [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Amortization expenses				500,000	400,000			800,000	500,000
TRIUMF Innovations Inc. [Member] | Collaboration Agreement and Amended Collaboration Agreement [Member] | Prepaid Expenses and Other Current Assets [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Milestone payment								2,100,000
TRIUMF Innovations Inc. [Member] | Collaboration Agreement and Amended Collaboration Agreement [Member] | Other Non-current Assets [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Milestone payment								1,600,000
NewCo [Member] | Asset Acquisition and License Agreement [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Assets held				0				0
Ipsen Pharma S A S | Asset Acquisition and License Agreement [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Upfront license fee paid						$ 800,000	€ 0.6
Research and development				0	0			$ 0	0
Common stock, shares issued | shares							600,000
Additional amount to be paid upon achievment of development and regulatory milestone | €							€ 67.5
Additional amount to be paid on net sales | €							350
Maximum amount of payments to be received for development milestones | €							€ 70
Ipsen Pharma S A S | Asset Acquisition and License Agreement [Member] | Maximum [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Decrease in percentage of royalties								50%
Collaboration And Supply Agreement With Niowave Inc [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Performance milestone payments based on successful development														$ 5,000,000
Collaboration And Supply Agreement With Niowave Inc [Member] | Asset Acquisition and License Agreement [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Performance milestone payments based on successful development				2,800,000				$ 2,800,000
Research and development				500,000	$ 100,000			700,000	$ 100,000
Milestone payment paid								1,900,000		$ 900,000
Collaboration And Supply Agreement With Niowave Inc [Member] | Asset Acquisition and License Agreement [Member] | Prepaid Expenses and Other Current Assets [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Milestone payment								1,200,000
Undisclosed Third-Party Agreement [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Upfront license fee paid				0.7				0.7
Undisclosed Third-Party Agreement [Member] | Sales Based Milestone [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Performance milestone payments based on successful development				50,000,000				50,000,000
Undisclosed Third-Party Agreement [Member] | Clinical And Regulatory Milestone [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Performance milestone payments based on successful development				$ 7,500,000				$ 7,500,000

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Operating Loss Carryforwards [Line Items]
Income tax provision (benefit)	$ (245,000)	$ (681,000)	$ (256,000)	$ (736,000)
Duration of research conducted with in united states			5 years
Duration of research conducted in abroad			15 years
Canada [Member]
Operating Loss Carryforwards [Line Items]
Income tax provision (benefit)	0	0
Tax credit carryforward amount	$ 0	$ 0	$ 0	$ 0

Net Loss per Share - Basic and

Net Loss per Share - Basic and Diluted Net Loss per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Numerator:
Net loss	$ (25,175)	$ (24,291)	$ (19,073)	$ (19,909)	$ (49,466)	$ (38,982)
Denominator:
Weighted-average common shares outstanding-basic	66,277,279		43,357,240		60,061,166	43,264,175
Weighted-average common shares outstanding-diluted	66,277,279		43,357,240		60,061,166	43,264,175
Net loss per share attributable to common shareholders — basic	$ (0.38)		$ (0.44)		$ (0.82)	$ (0.9)
Net loss per share attributable to common shareholders — diluted	$ (0.38)		$ (0.44)		$ (0.82)	$ (0.9)

Net Loss per Share - Summary of

Net Loss per Share - Summary of Potential Common Shares Excluded from Calculation of Diluted Net Loss per Share (Detail) - shares	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential common shares excluded from calculation of diluted net loss per share	14,420,613	10,024,558
Options to purchase common shares [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential common shares excluded from calculation of diluted net loss per share	14,158,993	9,924,748
Unvested Restricted Stock Units [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential common shares excluded from calculation of diluted net loss per share	65,500	73,700
Warrant Liability [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential common shares excluded from calculation of diluted net loss per share	196,120	26,110

Leases - Additional Information

Leases - Additional Information (Details) $ in Thousands, $ in Millions				1 Months Ended			6 Months Ended
	Jan. 12, 2022 USD ($)	Jun. 01, 2021 USD ($)	Jun. 01, 2021 CAD ($)	Feb. 28, 2023 USD ($)	Mar. 31, 2021 USD ($)	Oct. 31, 2019 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Lessee Lease Description [Line Items]
Operating lease expiration period	Aug. 31, 2030	Jun. 30, 2038	Jun. 30, 2038	Mar. 31, 2025		Feb. 28, 2026	Aug. 31, 2030
Operating lease additional lease period		5 years	5 years				5 years
Operating lease termination notice period							12 months
Operating lease, option to extend by lessee							false
Lessee, operating lease, description							In August 2018, the Company entered into an operating lease for office space in Hamilton, Ontario. This lease was amended in September 2020 (“New Lease Commencement Date”) and expires in August 2030 with a termination option upon twelve months written notice any time after the fifth anniversary of the New Lease Commencement Date. If the termination option is not exercised, the Company may exercise a renewal option to extend the term for an additional five-year period through August 2035. As the Company is not reasonably certain to extend the lease beyond the allowable termination date, the lease term was determined to end in August 2026 for the purposes of measuring this lease.
Restricted cash							$ 1,300		$ 1,500
Restricted cash, current							419		454
Restricted cash, noncurrent							$ 849		1,018
Allowance for lease improvements					$ 200
Lease improvements and expansions, description							The rental payments for the Expansion Space commenced on January 1, 2022.
Lease, option to extend	The lease has a five-year renewal option upon twelve months written notice prior to the expiration of the original term	The Company currently expects the rent for the manufacturing facility to commence in the third quarter of 2023. The Company currently expects the lease end date for the manufacturing facility to be in June 2038. The lease has a five-year renewal option, which the Company is not reasonably certain to exercise and therefore was not included in the expected lease term.	The Company currently expects the rent for the manufacturing facility to commence in the third quarter of 2023. The Company currently expects the lease end date for the manufacturing facility to be in June 2038. The lease has a five-year renewal option, which the Company is not reasonably certain to exercise and therefore was not included in the expected lease term.				The lease end date for the Original Premises and the Expansion Premises is April 30, 2027, with no option to extend the lease term.
Operating lease right-of-use assets	$ 300			$ 2,200	900		$ 17,632		5,684
Increase in operating lease liability	$ 300			$ 1,500	$ 1,200		16,130
Operating right-of-use asset obtained in exchange for an operating lease liability							12,947	$ 339
Hamilton Ontario [Member]
Lessee Lease Description [Line Items]
Operating lease right-of-use assets							10,800
Operating right-of-use asset obtained in exchange for an operating lease liability							8,900
Other Non-current Assets [Member] | Hamilton Ontario [Member]
Lessee Lease Description [Line Items]
Prepaid rent							2,100
Canada, Dollars
Lessee Lease Description [Line Items]
Initial direct cost expense			$ 2.5
United States of America, Dollars
Lessee Lease Description [Line Items]
Initial direct cost expense		$ 2,100
Letter of Credit [Member]
Lessee Lease Description [Line Items]
Restricted cash						$ 1,500	1,000
Restricted cash, current							200		200
Restricted cash, noncurrent							$ 800		$ 1,000

Leases - Component of Operating

Leases - Component of Operating Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Lease, Cost [Abstract]
Operating lease cost	$ 994	$ 369	$ 1,490	$ 735
Variable lease cost	127	27	149	40
Total lease cost	$ 1,121	$ 396	$ 1,639	$ 775

Leases - Summary of Supplementa

Leases - Summary of Supplemental Information, Operating Lease (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2023 USD ($)
Leases [Abstract]
Weighted-average remaining lease term (in years)	10 years 2 months 12 days
Weighted average discount rate	11%
Cash paid for amounts included in the measurement of lease liabilities (in thousands)	$ 1,009

Leases - Summary of Future Matu

Leases - Summary of Future Maturities of Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Feb. 28, 2023	Jan. 12, 2022	Mar. 31, 2021
Lessee, Operating Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
2023 (nine months)	$ 3,934
2024	3,135
2025	2,598
2026	2,357
2027	1,341
Thereafter	13,688
Total lease payments	27,053
Less: imputed interest	(10,923)
Total lease liabilities	$ 16,130	$ 1,500	$ 300	$ 1,200

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2023 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Non-cancelable minimum purchase commitments	$ 0.4
CPDC [Member]
Defined Benefit Plan Disclosure [Line Items]
Non-cancelable minimum purchase commitments	0.5
CPDC [Member] | Third Party Contract [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Non-cancelable minimum purchase commitments	$ 0.3

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - CPDC [Member] - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2022	Jun. 30, 2023
Related Party Transaction [Line Items]
Payment related to supply agreement per quarter			$ 200,000
Payment related to supply agreement aggregate per year			$ 900,000
Amounts of transaction related to service	$ 400,000	$ 1,100,000
Maximum [Member]
Related Party Transaction [Line Items]
Payment for reimbursement of pass through costs	100,000	100,000
Payment for lab equipment	$ 100,000	$ 200,000

Related Party Transactions - Sc

Related Party Transactions - Schedule of Recognized Expenses in Connection with Services Performed Under Master Services Agreement and Supply Agreement (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Related Party Transaction [Line Items]
Research and development expenses	$ 18,994	$ 12,076	$ 34,871	$ 24,737
General and administrative expenses	$ 7,753	7,781	$ 16,759	16,230
CPDC [Member]
Related Party Transaction [Line Items]
Research and development expenses		418		1,408
General and administrative expenses		3		17
Total operating expenses		$ 421		$ 1,425

Geographical Information - Sche

Geographical Information - Schedule of Long-lived Assets by Geographic Areas (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Revenues From External Customers And Long Lived Assets [Line Items]
Property and equipment, net	$ 5,709	$ 4,631
United States [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Property and equipment, net	405	465
Canada [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Property and equipment, net	$ 5,304	$ 4,166

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - $ / shares	Jun. 30, 2023	Dec. 31, 2022
Subsequent Event [Line Items]
Number of shares agreed to sell	68,990,263	44,805,627
Common stock, no par value	$ 0	$ 0