Wave Life Sciences (WVE) 10-K 23 Mar 23 2022 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2022	Mar. 10, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Trading Symbol	WVE
Entity Registrant Name	WAVE LIFE SCIENCES LTD.
Entity Central Index Key	0001631574
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Tax Identification Number	98-1356880
Entity Common Stock, Shares Outstanding		98,104,844
Entity Public Float			$ 205,332,422
Title of 12(b) Security	$0 Par Value Ordinary Shares
Security Exchange Name	NASDAQ
Entity File Number	001-37627
Entity Incorporation, State or Country Code	U0
Entity Address, Address Line One	7 Straits View #12-00
Entity Address, Address Line Two	Marina One
Entity Address, City or Town	East Tower
Entity Address, Country	SG
Entity Address, Postal Zip Code	018936
City Area Code	+65
Local Phone Number	6236 3388
Document Annual Report	true
Document Transition Report	false
Auditor Firm ID	185
Auditor Name	KPMG LLP
Auditor Location	Boston, Massachusetts
Documents Incorporated by Reference	If the Registrant’s Definitive Proxy Statement relating to the 2023 Annual General Meeting of Shareholders (the “Proxy Statement”) is filed with the Commission within 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K, then portions of the Proxy Statement will be incorporated by reference into Part III of this Annual Report on Form 10-K. If the Proxy Statement is not filed within such 120-day period, then the Registrant will file an amendment to this Annual Report within such 120-day period that will contain the information required to be included or incorporated by reference into Part III of this Annual Report.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 88,497	$ 150,564
Prepaid expenses	7,932	6,584
Other current assets	2,108	5,416
Total current assets	98,537	162,564
Long-term assets:
Property and equipment, net	17,284	22,266
Operating lease right-of-use assets	26,843	18,378
Restricted cash	3,660	3,651
Other assets	62	148
Total long-term assets	47,849	44,443
Total assets	146,386	207,007
Current liabilities:
Accounts payable	16,915	7,281
Accrued expenses and other current liabilities	17,552	14,861
Current portion of deferred revenue	31,558	37,098
Current portion of operating lease liability	5,496	4,961
Total current liabilities	71,521	64,201
Long-term liabilities:
Deferred revenue, net of current portion	79,774	77,479
Operating lease liability, net of current portion	32,118	24,955
Other liabilities	190
Total long-term liabilities	112,082	102,434
Total liabilities	183,603	166,635
Series A preferred shares, no par value; 3,901,348 shares issued and outstanding at December 31, 2022 and 2021	7,874	7,874
Shareholders' equity (deficit):
Ordinary shares, no par value; 86,924,643 and 59,841,116 shares issued and outstanding at December 31, 2022 and 2021, respectively	802,833	749,851
Additional paid-in capital	119,442	87,980
Accumulated other comprehensive income (loss)	(29)	181
Accumulated deficit	(967,337)	(805,514)
Total shareholders' equity (deficit)	(45,091)	32,498
Total liabilities, Series A preferred shares and shareholders' equity (deficit)	$ 146,386	$ 207,007

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Series A preferred stock, par value	$ 0	$ 0
Series A preferred stock, shares issued	3,901,348	3,901,348
Series A preferred stock, shares outstanding	3,901,348	3,901,348
Common stock, par value	$ 0	$ 0
Common stock, shares issued	86,924,643	59,841,116
Common stock, shares outstanding	86,924,643	59,841,116

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Revenue	$ 3,649	$ 40,964
Operating expenses:
Research and development	115,856	121,875
General and administrative	50,513	46,105
Total operating expenses	166,369	167,980
Loss from operations	(162,720)	(127,016)
Other income, net:
Dividend income and interest income, net	1,571	30
Other income, net	7	4,537
Total other income, net	1,578	4,567
Loss before income taxes	(161,142)	(122,449)
Income tax benefit (provision)	(681)	204
Net loss	$ (161,823)	$ (122,245)
Net loss per share attributable to ordinary shareholders basic	$ (2.05)	$ (2.36)
Net loss per share attributable to ordinary shareholders diluted	$ (2.05)	$ (2.36)
Weighted-average ordinary shares used in computing net loss per share attributable to ordinary shareholders basic.	78,855,810	51,825,566
Weighted-average ordinary shares used in computing net loss per share attributable to ordinary shareholders diluted	78,855,810	51,825,566
Other comprehensive income (loss):
Net loss	$ (161,823)	$ (122,245)
Foreign currency translation	(210)	(208)
Comprehensive loss	$ (162,033)	$ (122,453)

Consolidated Statements of Seri

Consolidated Statements of Series A Preferred Shares and Shareholders' Equity - USD ($) $ in Thousands	Total	At-The-Market Equity Program [Member]​	Series A Preferred Shares [Member]	Ordinary Shares [Member]	Ordinary Shares [Member] At-The-Market Equity Program [Member]​	Additional Paid-In-Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2020	$ 82,778			$ 694,085		$ 71,573	$ 389	$ (683,269)
Beginning balance, shares at Dec. 31, 2020				48,778,678
Temporary equity, Beginning balance at Dec. 31, 2020			$ 7,874
Temporary equity, Beginning balance, shares at Dec. 31, 2020			3,901,348
Issuance of ordinary shares		$ 54,908			$ 54,908
Issuance of ordinary shares, shares		10,740,915			10,740,915
Share-based compensation	16,407					16,407
Vesting of RSUs, shares				177,279
Option exercises	250			$ 250
Option exercises, shares				51,957
Issuance of ordinary shares under the ESPP	608			$ 608
Issuance of ordinary shares under ESPP, shares				92,287
Other comprehensive loss	(208)						(208)
Net loss	(122,245)							(122,245)
Ending balance at Dec. 31, 2021	32,498			$ 749,851		87,980	181	(805,514)
Ending balance, shares at Dec. 31, 2021				59,841,116
Temporary equity, Ending balance at Dec. 31, 2021	$ 7,874		$ 7,874
Temporary equity, Ending balance, shares at Dec. 31, 2021	3,901,348		3,901,348
Issuance of ordinary shares	$ 51,220	$ 1,167		$ 51,220	$ 1,167
Issuance of ordinary shares, shares		458,092		25,464,483	458,092
Issuance of pre-funded warrants, net of offering costs	14,268					14,268
Share-based compensation	17,194					17,194
Vesting of RSUs, shares				904,891
Option exercises	$ 223			$ 223
Option exercises, shares	90,000			90,000
Issuance of ordinary shares under the ESPP	$ 372			$ 372
Issuance of ordinary shares under ESPP, shares				166,061
Other comprehensive loss	(210)						(210)
Net loss	(161,823)							(161,823)
Ending balance at Dec. 31, 2022	(45,091)			$ 802,833		$ 119,442	$ (29)	$ (967,337)
Ending balance, shares at Dec. 31, 2022				86,924,643
Temporary equity, Ending balance at Dec. 31, 2022	$ 7,874		$ 7,874
Temporary equity, Ending balance, shares at Dec. 31, 2022	3,901,348		3,901,348

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities
Net loss	$ (161,823)	$ (122,245)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of right-of-use assets	3,540	2,352
Depreciation of property and equipment	6,574	7,483
Share-based compensation expense	17,194	16,407
Loss on disposal of property and equipment	12
Changes in operating assets and liabilities:
Accounts receivable		30,000
Prepaid expenses	(1,348)	3,850
Other assets	3,394	(338)
Accounts payable	9,348	(6,567)
Accrued expenses and other current liabilities	2,691	2,890
Deferred revenue	(3,245)	(18,464)
Operating lease liabilities	(4,308)	(3,887)
Other non-current liabilities	190	(474)
Net cash used in operating activities	(127,781)	(88,993)
Cash flows from investing activities
Purchases of property and equipment	(1,361)	(560)
Proceeds from the sale of property and equipment	106
Purchase of short-term investments	(75,044)
Proceeds from the maturity of short-term investments	75,044
Net cash used in investing activities	(1,255)	(560)
Cash flows from financing activities
Proceeds from issuance of ordinary shares, net of offering costs	51,220
Proceeds from issuance pre-funded warrants, net of offering costs	14,268
Proceeds from issuance of ordinary shares pursuant to the at-the-market equity program, net	1,105	54,970
Proceeds from the exercise of share options	223	250
Proceeds from the ESPP	372	608
Net cash provided by financing activities	67,188	55,828
Effect of foreign exchange rates on cash	(210)	(208)
Net in cash, cash equivalents and restricted cash	(62,058)	(33,933)
Cash, cash equivalents and restricted cash, beginning of period	154,215	188,148
Cash, cash equivalents and restricted cash, end of period	92,157	154,215
Supplemental disclosure of cash flow information:
Increase in operating lease right-of-use assets and lease liabilities related to new lease	$ 12,006	$ 4,498

The Company

The Company	12 Months Ended
	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
The Company	1. THE COMPANY Organization Wave Life Sciences Ltd. (together with its subsidiaries, “Wave” or the “Company”) is a clinical-stage genetic medicines company committed to delivering life-changing treatments for people battling devastating diseases. Using PRISM, Wave’s proprietary discovery and drug development platform that enables the precise design, optimization, and production of novel stereopure oligonucleotides, Wave is working to develop best- or first-in-class medicines that target the transcriptome (the full set of ribonucleic acid (“RNA”) molecules produced from the human genome) to treat genetically defined diseases with a high degree of unmet need. The Company was incorporated in Singapore on July 23, 2012 and has its principal U.S. office in Cambridge, Massachusetts. The Company was incorporated with the purpose of combining two commonly held companies, Wave Life Sciences USA, Inc. (“Wave USA”), a Delaware corporation (formerly Ontorii, Inc.), and Wave Life Sciences Japan, Inc. (“Wave Japan”), a company organized under the laws of Japan (formerly Chiralgen., Ltd.), which occurred on September 13, 2012. On May 31, 2016, Wave Life Sciences Ireland Limited (“Wave Ireland”) was formed as a wholly - owned subsidiary of Wave Life Sciences Ltd. On April 3, 2017, Wave Life Sciences UK Limited (“Wave UK”) was formed as a wholly - owned subsidiary of Wave Life Sciences Ltd. The Company’s primary activities since inception have been developing and evolving PRISM to design, develop and commercialize oligonucleotide therapeutics, advancing the Company’s differentiated portfolio, building the Company’s research, development and manufacturing capabilities, advancing programs into the clinic, furthering clinical development of such clinical-stage programs, building the Company’s intellectual property, and assuring adequate capital to support these activities. Liquidity Since its inception, the Company has not generated any product revenue and has incurred recurring net losses. To date, the Company has primarily funded its operations through private placements of debt and equity securities, public and other registered offerings of its equity securities and collaborations with third parties. Until the Company can generate significant revenue from product sales, if ever, the Company expects to continue to finance operations through a combination of public or private equity or debt financings or other sources, which may include collaborations with third parties. Adequate additional financing may not be available to the Company on acceptable terms, or at all. The inability to raise capital as and when needed would have a negative impact on the Company’s financial condition and ability to pursue its business strategy. As of December 31, 2022, the Company had cash and cash equivalents of $ 88.5 million. Subsequent to December 31, 2022 , the Company received $ 170.0 million in cash, of which $ 120.0 million was an upfront payment under the GSK Collaboration Agreement (as defined in note 14) and $ 50.0 million was the GSK Equity Investment (as defined in note 14). The Company expects that its existing cash and cash equivalents will be sufficient to fund its operations for at least the next twelve months. The Company has based this expectation on assumptions that may prove to be incorrect, and the Company may use its available capital resources sooner than it currently expects. If the Company’s anticipated operating results are not achieved in future periods, planned expenditures may need to be further reduced in order to extend the time period over which the then-available resources would be able to fund the Company’s operations. In addition, the Company may elect to raise additional funds before it needs them if the conditions for raising capital are favorable due to market conditions or strategic considerations, even if the Company expects it has sufficient funds for its current or future operating plans. Risks and Uncertainties The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, maintaining internal manufacturing capabilities, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. The Company’s therapeutic programs will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval, prior to commercialization of any product candidates. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance-reporting capabilities. There can be no assurance that the Company’s research and development efforts will be successful, that adequate protection for the Company’s intellectual property will be obtained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. Basis of Presentation The Company has prepared the accompanying consolidated financial statements in conformity with generally accepted accounting principles in the United States (“U.S. GAAP”) and in U.S. dollars.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Significant Accounting Policies	2. SIGNIFICANT ACCOUNTING POLICIES Cash and Cash Equivalents The Company considers all highly liquid securities with maturities of three months or less from the date of purchase to be cash equivalents. The Company's cash and cash equivalents are comprised of funds held in checking and money market accounts. Short-Term Investments The Company’s short-term investments consist of term deposits. Principles of Consolidation The Company’s consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Use of Estimates The preparation of financial statements in conformity with U.S. 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 consolidated financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include the assumptions used to determine the fair value of share-based awards, the Company’s revenue recognition policy, particularly, (a) assessing the number of performance obligations; (b) determining the transaction price; (c) allocating the transaction price to the performance obligations in the contract; and (d) determining the pattern over which performance obligations are satisfied, including estimates to complete performance obligations, the evaluation of progress to completion of external research and development costs which can result in prepaid or accrued expenses related to the Company’s contract research organizations (“CROs”) and contract manufacturing organizations (“CMOs”), the valuation allowance required for the Company’s deferred tax assets, determining uncertain tax positions and the related liabilities, and estimating refundable tax credits. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Actual results could differ from the Company’s estimates. Segment Data The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The Company’s singular focus is on developing its proprietary discovery and drug development platform, PRISM, to develop and commercialize a broad pipeline of nucleic acid-based therapeutics, or oligonucleotides. Going Concern At each reporting period, the Company evaluates whether there are conditions or events that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the financial statements are issued. The Company is required to make certain additional disclosures if the Company concludes substantial doubt exists and it is not alleviated by the Company’s plans or when the Company’s plans alleviate substantial doubt about the Company’s ability to continue as a going concern. The Company’s evaluation entails analyzing prospective operating budgets and forecasts for expectations of the Company’s cash needs and comparing those needs to the current cash and cash equivalent balance. Foreign Currency Translation The functional currency is the U.S. dollar for all of the Company’s entities aside from Wave Japan, which has the Japanese Yen as its functional currency. Assets and liabilities of Wave Japan are translated at period end exchange rates while revenues and expenses of Wave Japan are translated at average exchange rates for the period. Net unrealized gains and losses from foreign currency translation are reflected as other comprehensive income (loss) within the consolidated statements of Series A preferred shares and shareholders’ equity (deficit) and the consolidated statements of operations and comprehensive loss. Gains and losses on foreign currency transactions are included in the consolidated statements of operations and comprehensive loss within other income, net. Fair Value of Financial Instruments The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. The fair value hierarchy is a hierarchy of inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the financial instrument based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the financial instrument and are developed based on the information available in the circumstances. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value of the investments and is not a measure of the investment credit quality. The hierarchy defines three levels of valuation inputs: Level 1—Unadjusted quoted prices in active markets that are accessible at the measurement date of identical, unrestricted assets. Level 2—Quoted prices for similar assets, or inputs that are observable, either directly or indirectly, for substantially the full term through corroboration with observable market data. Level 2 includes investments valued at quoted prices adjusted for legal or contractual restrictions specific to the security. Level 3—Pricing inputs are unobservable for the asset, that is, inputs that reflect the reporting entity’s own assumptions about the assumptions market participants would use in pricing the asset. Level 3 includes private investments that are supported by little or no market activity. Cash, cash equivalents and restricted cash are Level 1 assets which are comprised of funds held in checking and money market accounts. Short-term investments are Level 2 assets which are comprised of term deposits. Cash, cash equivalents and restricted cash were recorded at fair value as of December 31, 2022 and 2021, totaling $ 92.2 million and $ 154.2 million, respectively. There were no short-term investments as of December 31, 2022 or 2021 , as the $ 75.0 million of term deposits that constitute the Company’s short-term investments were all purchased and reached maturity during the twelve months ended December 31, 2022 . The carrying amounts of accounts payable and accrued expenses approximate their fair values due to their short-term maturities. Concentration of Credit Risk Cash, cash equivalents, restricted cash and short-term investments are financial instruments that potentially subject the Company to concentration of credit risk. The Company uses several financial institutions to maintain its cash, cash equivalents, restricted cash and short-term investments, all of which are high quality, accredited financial institutions and, accordingly, such funds are subject to minimal credit risk. The Company has not experienced any losses in such accounts and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company has no financial instruments with off-balance sheet risk of loss. Restricted Cash Restricted cash consists primarily of cash placed in separate restricted bank accounts as required under the terms of the Company’s lease agreements for its Cambridge, Massachusetts and Lexington, Massachusetts facilities (refer to Note 8). As of December 31, 2022 and 2021 , the Company had $ 3.7 million of restricted cash, of which $ 2.7 million related to the Lexington facility and $ 1.0 million related to the Cambridge facility. Property and Equipment Property and equipment, which consists primarily of equipment, furniture, software and leasehold improvements, are stated at cost less accumulated depreciation. Depreciation is calculated on a straight-line basis over the following estimated useful lives of the assets: Equipment, Furniture and Software 3 - 7 years Leasehold Improvements Shorter of asset life or lease term Depreciation begins at the time the asset is placed in service. Maintenance and repairs are charged to operations as incurred. Upon retirement or sale, the cost of the disposed asset and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is reflected in the consolidated statements of operations and comprehensive loss. Impairment of Long-Lived Assets Long-lived assets consist of property and equipment. Long-lived assets are reviewed for impairment whenever events or other changes in circumstances indicate that the carrying amount may not be recoverable. Certain factors may exist or events may occur that indicate that impairment exists including, but not limited to, the following: significant underperformance relative to historical or projected future operating results; significant changes in the manner of use of the underlying assets; and significant adverse industry or market economic trends. When performing the impairment assessment for long-lived assets, the Company compares the carrying value of such assets to the estimated undiscounted future net cash flows expected from the use of the assets and their eventual disposition. In the event that the carrying value of the assets is determined to be unrecoverable, the Company would estimate the fair value of the assets and record an impairment charge for the excess of the carrying value over the fair value. Revenue Recognition The Company recognizes revenue in accordance with Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers (“ASC 606”). This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, and financial instruments. Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five-step analysis: (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 in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step analysis to contracts when it is probable that the entity will collect the consideration to which it is entitled 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 each contract, determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. The Company has entered into collaboration agreements for research, development, and commercial services, under which the Company licenses certain rights to its product candidates to third parties. The terms of these arrangements typically include payment to the Company of one or more of the following: non-refundable, upfront license fees; reimbursement of certain costs; customer option exercise fees; development, regulatory and commercial milestone payments; and royalties on net sales of licensed products. Any variable consideration is constrained and, therefore, the cumulative revenue associated with this consideration is not recognized until it is deemed not to be at significant risk of reversal. In determining the appropriate amount of revenue to be recognized as the Company fulfills its obligations under each of its agreements for which the collaboration partner is also a customer, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations, including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. As part of the accounting for these arrangements, the Company must use significant judgment to determine: (a) the number of performance obligations based on the determination under step (ii) above; (b) the transaction price under step (iii) above; and (c) the timing of satisfaction of performance obligations as a measure of progress in step (v) above. The Company uses significant judgment to determine whether milestones or other variable consideration, except for royalties, should be included in the transaction price as described further below. The transaction price is allocated to the optional goods and services the Company expects to provide. The Company uses estimates to determine the timing of satisfaction of performance obligations. Amounts received prior to being recognized as revenue are recorded as deferred revenue. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as current portion of deferred revenue in the accompanying consolidated balance sheets. 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. Licenses of intellectual property: In assessing whether a promise or performance obligation is distinct from the other promises, the Company considers factors such as the research, development, manufacturing and commercialization capabilities of the customer and the availability of the associated expertise in the general marketplace. In addition, the Company considers whether the customer can benefit from a promise for its intended purpose without the receipt of the remaining promise, whether the value of the promise is dependent on the unsatisfied promise, whether there are other vendors that could provide the remaining promise, and whether it is separately identifiable from the remaining promise. For licenses that are combined 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. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Research and development services : If an arrangement is determined to contain a promise or obligation for the Company to perform research and development services, the Company must determine whether these services are distinct from other promises in the arrangement. In assessing whether the services are distinct from the other promises, the Company considers the capabilities of the customer to perform these same services. In addition, the Company considers whether the customer can benefit from a promise for its intended purpose without the receipt of the remaining promise, whether the value of the promise is dependent on the unsatisfied promise, whether there are other vendors that could provide the remaining promise, and whether it is separately identifiable from the remaining promise. For research and development services that are combined 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. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Customer options: If an arrangement is determined to contain customer options that allow the customer to acquire additional goods or services, the goods and services underlying the customer options are not considered to be performance obligations at the outset of the arrangement, as they are contingent upon option exercise. The Company evaluates the customer options for material rights, that is, the option to acquire additional goods or services for free or at a discount. If the customer options are determined to represent a material right, the material right is recognized as a separate performance obligation at the outset of the arrangement. The Company allocates the transaction price to material rights based on the standalone selling price. As a practical alternative to estimating the standalone selling price when the goods or services are both (i) similar to the original goods and services in the contract and (ii) provided in accordance with the terms of the original contract, the Company allocates the total amount of consideration expected to be received from the customer to the total goods or services expected to be provided to the customer. Amounts allocated to any material right are not recognized as revenue until the option is exercised and the performance obligation is satisfied. Milestone payments: At the inception of each arrangement that includes milestone payments, the Company evaluates whether a significant reversal of cumulative revenue provided in conjunction with achieving the milestones is probable, and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant reversal of cumulative revenue would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. For other milestones, the Company evaluates factors such as the scientific, clinical, regulatory, commercial, and other risks that must be overcome to achieve the particular milestone in making this assessment. There is considerable judgment involved in determining whether it is probable that a significant reversal of cumulative revenue would not occur. At the end of each subsequent reporting period, the Company reevaluates the probability of achievement of all milestones subject to constraint and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. Royalties: For arrangements that include sales-based royalties, including milestone payments based on a level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes 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). To date, the Company has not recognized any royalty revenue resulting from any of its licensing arrangements. Contract costs : The Company recognizes as an asset the incremental costs of obtaining a contract with a customer if the costs are expected to be recovered. As a practical expedient, the Company recognizes the incremental costs of obtaining a contract as an expense when incurred if the amortization period of the asset that it otherwise would have recognized is one year or less. To date, the Company has not incurred any incremental costs of obtaining a contract with a customer. Research and Development Expenses Research and development expenses are expensed as incurred. External development costs are recognized based on an evaluation of the progress to completion of specific tasks. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in the accompanying consolidated balance sheets as prepaid or accrued expenses. License Agreements and Patent Costs Costs associated with licenses of technology and patent costs are expensed as incurred and are generally included in research and development expense in the consolidated statements of operations and comprehensive loss. Refundable Tax Credits The Company is eligible for refundable tax credits with tax authorities for certain qualified operating expenses. The Company recognizes refundable tax credits when there is reasonable assurance that the Company will comply with the requirements of the refundable tax credit and that the refundable tax credit will be received. Refundable tax credits are recorded as income and classified in other income, net in the consolidated statements of operations and comprehensive loss. Net Loss per Share Basic net loss per share is computed using the weighted-average number of ordinary shares outstanding during the period. The outstanding Pre-Funded Warrants (as defined in note 6) are included in the weighted-average number of ordinary shares outstanding used in the calculation of basic net loss per share as the exercise price is negligible and the warrants are fully vested and exercisable. Diluted net loss per share is computed using the sum of the weighted-average number of ordinary shares outstanding during the period and, if dilutive, the weighted-average number of potential ordinary shares, including the assumed exercise of share options and the assumed vesting of RSUs (as defined in note 7). The Company applies the two-class method to calculate its basic and diluted net loss per share attributable to ordinary shareholders, as its Series A preferred shares are participating securities. The two-class method is an earnings allocation formula that treats a participating security as having rights to earnings that otherwise would have been available to ordinary shareholders. However, for the periods presented, the two-class method does not impact the net loss per ordinary share as the Company was in a net loss position for each of the periods presented and holders of Series A preferred shares do not participate in losses. The Company’s Series A preferred shares contractually entitle the holders of such shares to participate in dividends but do not contractually require the holders of such shares to participate in losses of the Company. Accordingly, for periods in which the Company reports a net loss attributable to ordinary shareholders, diluted net loss per share attributable to ordinary shareholders is the same as basic net loss per share attributable to ordinary shareholders, since dilutive ordinary shares are not assumed to have been issued if their effect is anti-dilutive. Share-Based Compensation The Company measures and recognizes share-based compensation expense, for both employee and director option awards, based on the grant date fair value of the awards. The Company calculates the fair value of restricted share unit awards based on the grant date fair value of the underlying ordinary shares. The Company determines the fair value of share-based awards granted to non-employees as either the fair value of the consideration received or the fair value of the equity instruments issued, whichever is more reliably measurable. Equity instruments issued to non-employees as consideration for goods or services received by the Company have been accounted for based on the fair value of the equity instruments issued. The Company recognizes share-based compensation expense on a straight-line basis over the requisite service period of the awards, which is generally the vesting period. The Company accounts for forfeitures as they occur. The Company classifies share-based compensation expense in its consolidated statements of operations and comprehensive loss in the same manner in which the award recipient’s compensation costs are classified or in which the award recipient’s service payments are classified. The fair value of each share option grant was determined using the methods and assumptions discussed below. These inputs are generally subjective and require significant judgment and estimation by management. • Fair Value of Ordinary Shares The fair value of the ordinary shares underlying the Company’s share-based awards is based on the closing price of the Company’s ordinary shares as reported by the Nasdaq Global Market on the date of grant. • Expected Term The expected term of share options represents the weighted-average period that the share options are expected to remain outstanding. The Company estimated the expected term using the simplified method, which is an average of the contractual term of the option and the vesting period. • Expected Volatility Since there was limited historical data for the Company’s ordinary shares and limited company-specific historical volatility through the third quarter of 2021, the Company determined the share price volatility for options granted based on an analysis of the volatility used by a peer group of publicly traded companies. In evaluating similarity, the Company considers factors such as industry, stage of life cycle and size. Beginning in the fourth quarter of 2021, the Company had sufficient historical volatility data for its ordinary shares and as such no longer relies on an analysis of the volatility from a peer group to calculate expected volatility. • Risk-free Interest Rate The risk-free interest rate is based on the U.S. Treasury yield in effect at the time of the grant for zero-coupon U.S. Treasury notes with remaining terms similar to the expected term of the options. • Dividend Rate The expected dividend was assumed to be zero as the Company has never paid dividends and has no current plans to do so. Income Taxes The Company accounts for income taxes using an asset and liability approach, which requires recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the consolidated financial statements but have not been reflected in taxable income. A valuation allowance is established to reduce deferred tax assets to their estimated realizable value. Therefore, the Company provides a valuation allowance to the extent that it is more likely than not that all or a portion of the deferred tax assets will not be realized in the future. The Company accounts for uncertainty in income taxes recognized in the financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the tax authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50 % likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties. The Company recognizes interest and penalties related to uncertain tax positions in the income tax provision on the consolidated statements of operations and comprehensive loss. The Company has certain service arrangements in place between its U.S., Japan, U.K. and Singapore entities, which include transfer pricing assumptions. The determination of the appropriate level of transfer pricing requires judgment based on transfer pricing analyses of comparable companies. The Company monitors the nature of its service arrangements for changes in its operations as well as economic conditions. The Company also periodically reviews the transfer pricing analyses for changes in the composition in the pool of comparable companies as well as the related ongoing results of the comparable companies. Leases The Company accounts for leases in accordance with ASC Topic 842, Leases (“ASC 842”). At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present in the arrangement. Most leases with a term greater than one year are recognized on the balance sheet as right-of-use assets and short-term and long-term lease liabilities, as applicable. The Company typically only includes an initial lease term in its assessment of a lease arrangement. Options to renew a lease are not included in the Company’s assessment unless there is reasonable certainty that the Company will renew the lease. The Company monitors its plans to renew its leases on a quarterly basis. Certain lease agreements include rental payments that are adjusted periodically for inflation or other variables. In addition to rent, the leases may require the Company to pay additional amounts for taxes, insurance, maintenance, or other expenses, which are generally referred to as non-lease components. Such adjustments to rental payments and variable non-lease components are treated as variable lease payments and recognized in the period in which the obligation for these payments are incurred. Variable lease components and variable non-lease components are not measured as part of the right-of-use asset and lease liability. Only when lease components and their associated non-lease components are fixed are they accounted for as a single lease component and are recognized as part of a right-of-use asset and lease liability. Total contract consideration is allocated to the combined fixed lease and non-lease component. This policy election applies consistently to all asset classes under lease agreements. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected remaining lease term. Certain adjustments to the right-of-use asset may be required for items such as incentives received. The interest rate implicit in lease contracts is typically not readily determinable. As a result, the Company utilizes its incremental borrowing rate, which reflects the fixed rate at which the Company could borrow on a collateralized basis the amount of the lease payments in the same currency, for a similar term, in a similar economic environment. Accounting Pronouncements There were no recently issued or adopted accounting pronouncements that would have a material impact on the Company's consolidated financial statements.

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	3. PROPERTY AND EQUIPMENT, NET Property and equipment, net, consists of the following: December 31, 2022 2021 (in thousands) Furniture and equipment $ 25,509 $ 25,657 Software 890 817 Leasehold improvements 28,413 27,994 Fixed assets in progress 318 28 Total 55,130 54,496 Less accumulated depreciation ( 37,846 ) ( 32,230 ) Property and equipment, net $ 17,284 $ 22,266 Substantially all of the Company’s long-lived assets were located in the United States as of December 31, 2022 and 2021. Depreciation expense was $ 6.6 million and $ 7.5 million for the years ended December 31, 2022 and 2021 , respectively.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	4. ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES Accrued expenses and other current liabilities consist of the following: December 31, 2022 2021 (in thousands) Accrued compensation $ 12,287 $ 10,181 Accrued expenses related to CROs and CMOs 3,516 3,571 Accrued expenses and other current liabilities 1,749 1,109 Total accrued expenses and other current liabilities $ 17,552 $ 14,861

Collaboration Agreements

Collaboration Agreements	12 Months Ended
	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration Agreements	5. COLLABORATION AGREEMENTS Takeda Collaboration and Equity Agreements In February 2018 , Wave USA and Wave UK entered into a global strategic collaboration (the “Takeda Collaboration”) with Takeda Pharmaceutical Company Limited (“Takeda”), pursuant to which Wave USA, Wave UK and Takeda agreed to collaborate on the research, development and commercialization of oligonucleotide therapeutics for disorders of the Central Nervous System (“CNS”). The Takeda Collaboration provides the Company with at least $ 230.0 million in committed cash and Takeda with the option to co-develop and co-commercialize the Company’s CNS development programs in (1) Huntington’s disease (“HD”); (2) amyotrophic lateral sclerosis (“ALS”) and frontotemporal dementia (“FTD”); and (3) the Company’s discovery-stage program targeting ATXN3 for the treatment of spinocerebellar ataxia 3 (“SCA3”) (collectively, “Category 1 Programs”). In addition, the Takeda Collaboration provided Takeda the right to exclusively license multiple preclinical programs for CNS disorders, including Alzheimer’s disease and Parkinson’s disease (collectively, “Category 2 Programs”). In April 2018, the Takeda Collaboration became effective and Takeda paid the Company $ 110.0 million as an upfront payment. Takeda also agreed to fund the Company’s research and preclinical activities in the amount of $ 60.0 million during the four-year research term and to reimburse the Company for any collaboration-budgeted research and preclinical expenses incurred by Wave that exceed that amount. Simultaneously with Wave USA and Wave UK’s entry into the collaboration and license agreement with Takeda (the “Takeda Collaboration Agreement”), the Company entered into a share purchase agreement with Takeda (the “Takeda Equity Agreement,” and together with the Takeda Collaboration Agreement, the “Takeda Agreements”) pursuant to which it agreed to sell to Takeda 1,096,892 of its ordinary shares at a purchase price of $ 54.70 per share. In April 2018 , the Company closed the Takeda Equity Agreement and received aggregate cash proceeds of $ 60.0 million. The Company did not incur any material costs in connection with the issuance of shares. With respect to Category 1 Programs, the Company will be responsible for researching and developing products and companion diagnostics for Category 1 Programs through completion of the first proof of mechanism study for such products. Takeda will have an exclusive option for each target and all associated products and companion diagnostics for such target, which it may exercise at any time through completion of the proof of mechanism study. If Takeda exercises this option, the Company will receive an opt-in payment and will lead manufacturing and joint clinical co-development activities and Takeda will lead joint co-commercial activities in the United States and all commercial activities outside of the United States. Global costs and potential profits will be shared 50 : 50 and the Company will be eligible to receive development and commercial milestone payments. In addition to its 50% profit share, the Company is eligible to receive option exercise fees and development and commercial milestone payments for each of the Category 1 Programs. With respect to Category 2 Programs, the Company granted Takeda the right to exclusively license multiple preclinical programs during a four-year research term (subject to limited extension for programs that were initiated prior to the expiration of the research term, in accordance with the Takeda Collaboration Agreement) (“Category 2 Research Term”). During that term, the Takeda Collaboration provided that the parties may collaborate on preclinical programs for up to six targets at any one time . The Company was responsible for researching and preclinically developing products and companion diagnostics directed to the agreed upon targets through completion of Investigational New Drug application (“IND”)-enabling studies in the first major market country. Thereafter, Takeda would have an exclusive worldwide license to develop and commercialize products and companion diagnostics directed to such targets, subject to the Company’s retained rights to lead manufacturing activities for products directed to such targets. Takeda agreed to fund the Company’s research and preclinical activities in the amount of $ 60.0 million during the research term and reimburse the Company for any collaboration-budgeted research and preclinical expenses incurred by the Company that exceeded that amount. The Company was also eligible to receive tiered high single-digit to mid-teen royalties on Takeda’s global commercial sales of products from each Category 2 Program. Under the Takeda Collaboration Agreement, each party granted to the other party specific intellectual property licenses to enable the other party to perform its obligations and exercise its rights under the Takeda Collaboration Agreement, including license grants to enable each party to conduct research, development and commercialization activities pursuant to the terms of the Takeda Collaboration Agreement. The term of the Takeda Collaboration Agreement commenced on April 2, 2018 and, unless terminated earlier, will continue until the date on which: (i) with respect to each Category 1 Program target for which Takeda does not exercise its option, the expiration or termination of the development program with respect to such target; (ii) with respect to each Category 1 Program target for which Takeda exercises its option, the date on which neither party is researching, developing or manufacturing any products or companion diagnostics directed to such target; or (iii) with respect to each Category 2 Program target, the date on which royalties are no longer payable with respect to products directed to such target. Takeda may terminate the Takeda Collaboration Agreement for convenience on 180 days ’ notice, in its entirety or on a target-by-target basis. Subject to certain exceptions, each party has the right to terminate the Takeda Collaboration Agreement on a target-by-target basis if the other party, or a third party related to such party, challenges the patentability, enforceability or validity of any patents within the licensed technology that cover any product or companion diagnostic that is subject to the Takeda Collaboration Agreement. In the event of any material breach of the Takeda Collaboration Agreement by a party, subject to cure rights, the other party may terminate the Takeda Collaboration Agreement in its entirety if the breach relates to all targets or on a target-by-target basis if the breach relates to a specific target. In the event that Takeda and its affiliates cease development, manufacturing and commercialization activities with respect to compounds or products subject to the Takeda Collaboration Agreement and directed to a particular target, the Company may terminate the Takeda Collaboration Agreement with respect to such target. Either party may terminate the Takeda Collaboration Agreement for the other party’s insolvency. In certain termination circumstances, the Company would receive a license from Takeda to continue researching, developing and manufacturing certain products, and companion diagnostics. The Takeda Collaboration is managed by a joint steering committee in which both parties are represented equally. The joint steering committee is tasked with overseeing the scientific progression of each Category 1 Program and, prior to the Amendment (discussed below), the Category 2 Programs. The Company assessed this arrangement in accordance with ASC 606 and concluded that the contract counterparty, Takeda, is a customer for Category 1 Programs prior to Takeda exercising its option, and for Category 2 Programs during the Category 2 Research Term. The Company identified the following material promises under the arrangement: (1) the non-exclusive, royalty-free research and development license for each Category 1 Program; (2) the research and development services for each Category 1 Program through completion of the first proof of mechanism study; (3) the exclusive option to license, co-develop and co-commercialize each Category 1 Program; (4) the right to exclusively license the Category 2 Programs; and (5) the research and preclinical development services of the Category 2 Programs through completion of IND-enabling studies. The research and development services for each Category 1 Program were determined to not be distinct from the research and development license and should therefore be combined into a single performance obligation for each Category 1 Program. The research and preclinical development services for the Category 2 Programs were determined to not be distinct from the exclusive licenses for the Category 2 Programs and should therefore were combined into a single performance obligation. Additionally, the Company determined that the exclusive option for each Category 1 Program was priced at a discount and, as such, provide material rights to Takeda, representing three separate performance obligations. Based on these assessments, the Company identified seven performance obligations in the Takeda Collaboration Agreement: (1) research and development services through completion of the first proof of mechanism and non-exclusive research and development license for HD; (2) research and development services through completion of the first proof of mechanism and non-exclusive research and development license for ALS and FTD; (3) research and development services through completion of the first proof of mechanism and non-exclusive research and development license for SCA3; (4) the material right provided for the exclusive option to license, co-develop and co-commercialize HD; (5) the material right provided for the exclusive option to license, co-develop and co-commercialize ALS and FTD; (6) the material right provided for the exclusive option to license, co-develop and co-commercialize SCA3; and (7) the research and preclinical development services and right to exclusively license the Category 2 Programs. At the outset of the arrangement, the transaction price included the $ 110.0 million upfront consideration received and the $ 60.0 million of committed research and preclinical funding for the Category 2 Programs. The Company determined that the Takeda Collaboration Agreement did not contain a significant financing component. The option exercise fees to license, co-develop and co-commercialize each Category 1 Program that may be received are excluded from the transaction price until each customer option is exercised. The potential milestone payments were excluded from the transaction price, as all milestone amounts were fully constrained at the inception of the Takeda Collaboration Agreement. The Company will reevaluate the transaction price at the end of each reporting period and, as uncertain events are resolved or other changes in circumstances occur, if necessary, will adjust its estimate of the transaction price. The Company allocated the transaction price to the performance obligations on a relative standalone selling price basis. For the performance obligations associated with the research and development services through completion of the first proof of mechanism and non-exclusive research and development license for HD; the research and development services through completion of the first proof of mechanism and non-exclusive research and development license for ALS and FTD; the research and development services through completion of the first proof of mechanism and non-exclusive research and development license for SCA3; and the research and preclinical development services and right to exclusively license the Category 2 Programs, the Company determined the standalone selling price using estimates of the costs to perform the research and development services, including expected internal and external costs for services and supplies, adjusted to reflect a profit margin. The total estimated cost of the research and development services reflected the nature of the services to be performed and the Company’s best estimate of the length of time required to perform the services. For the performance obligations associated with the material right provided for the exclusive option to license, co-develop and co-commercialize HD; the material right provided for the exclusive option to license, co-develop and co-commercialize ALS and FTD; and the material right provided for the exclusive option to license, co-develop and co-commercialize SCA3, the Company estimated the standalone fair value of the option to license each Category 1 Program utilizing an adjusted market assessment approach, and determined that any standalone fair value in excess of the amounts to be paid by Takeda associated with each option represented a material right. Revenue associated with the research and development services for each Category 1 Program performance obligation is being recognized as the research and development services are provided using an input method, according to the costs incurred on each Category 1 Program and the total costs expected to be incurred to satisfy each Category 1 Program performance obligation. Prior to the Amendment described below, revenue associated with the research and preclinical development services for the Category 2 Programs performance obligation was recognized as the research and preclinical development services that were provided using an input method, according to the costs incurred on Category 2 Programs and the total costs expected to be incurred to satisfy the performance obligation. The amount allocated to the material right for each Category 1 Program option will be recognized on the date that Takeda exercises each respective option, or immediately as each option expires unexercised. The amounts received that have not yet been recognized as revenue are recorded in deferred revenue on the Company’s consolidated balance sheet. On October 15, 2021 , Wave USA, Wave UK and Takeda entered into the Second Amendment to the Takeda Collaboration Agreement (the “Amendment”), which discontinued the Category 2 component of the Takeda Collaboration. The Category 1 Programs under the Collaboration Agreement remain in effect and are unchanged by the Amendment. Pursuant to the Amendment, Takeda agreed to pay the Company an additional $ 22.5 million as full payment for reimbursable Category 2 Programs collaboration-budgeted research and preclinical expenses. The Company received this payment from Takeda related to the Category 2 component and recognized the full amount as collaboration revenue in the year ended December 31, 2021. During the year ended December 31, 2021, in addition to the revenue recognized related to the Amendment, the Company recognized another $ 18.5 million of collaboration revenue related to services pertaining to the Category 1 Programs and Category 2 Programs. During the years ended December 31, 2022 and 2021 , the Company recognized revenue of approximately $ 3.3 million and $ 41.0 million, respectively, under the Takeda Collaboration Agreement in the Company’s consolidated statements of operations and comprehensive loss. Through December 31, 2022 , the Company had recognized revenue of $ 81.2 million under the Takeda Collaboration Agreement as collaboration revenue in the Company’s consolidated statements of operations and comprehensive loss. The aggregate amount of the transaction price allocated to the Company’s unsatisfied and partially unsatisfied performance obligations and recorded in deferred revenue as of December 31, 2022 and 2021, was $ 111.3 million and $ 114.6 million, respectively. The deferred revenue included in current liabilities as of December 31, 2022 and 2021, was approximately $ 31.6 million and $ 37.1 million, respectively. The deferred revenue included in long-term liabilities as of December 31, 2022 and 2021, was $ 79.8 million and approximately $ 77.5 million, respectively. The increase in the long-term portion of deferred revenue was due to an increase in the period over which certain Category 1 Program performance obligations are expected to be satisfied, which led to a corresponding decrease to the current portion of deferred revenue as of December 31, 2022. Additionally, the current portion of deferred revenue decreased from December 31, 2021 to December 31, 2022 due to revenue recognized during the year ended December 31, 2022 . The Company expects to recognize revenue for the portion of the deferred revenue that relates to the research and development services for each Category 1 Program as costs are incurred over the remaining research term. The Company expects to recognize revenue for the portion of the deferred revenue that relates to the material right for each Category 1 Program option upon Takeda’s exercise of such option, or immediately as each option expires unexercised.

Share Capital

Share Capital	12 Months Ended
	Dec. 31, 2022
Equity [Abstract]
Share Capital	6. SHARE CAPITAL The following represents the Company’s financing transactions during the years ended December 31, 2022 and 2021: • The Company entered into an open market sales agreement with Jefferies LLC in May 2019, as amended in March 2020 and March 2022, for its at-the-market equity program. During the year ended December 31, 2021 , the Company sold 10,740,915 ordinary shares under its at-the-market equity program for aggregate net proceeds of $ 54.9 million after deducting commissions and offering expenses. During the year ended December 31, 2022 , the Company sold 458,092 ordinary shares under its at-the-market equity program for aggregate net proceeds of $ 1.2 million after deducting commissions and offering expenses. • On June 16, 2022, the Company closed an underwritten offering (the “June 2022 Offering”) in which the Company issued and sold 25,464,483 of the Company’s ordinary shares at a price of $ 2.15 per share and pre-funded warrants (the “Pre-Funded Warrants”) to purchase up to 7,093,656 of the Company’s ordinary shares at an offering price of $ 2.1499 per Pre-Funded Warrant, which represents the per share offering price for the ordinary shares less the $ 0.0001 per share exercise price for each Pre-Funded Warrant. These Pre-Funded Warrants were recorded as a component of shareholders’ equity within additional paid-in capital. The gross proceeds to the Company from the June 2022 Offering were $ 70.0 million before deducting underwriting discounts and commissions and other offering expenses. The net proceeds to the Company from the June 2022 Offering were approximately $ 65.5 million after deducting underwriting commissions and offering expenses. The Pre-Funded Warrants are exercisable at any time after their original issuance and on or prior to the five-year anniversary of the original issuance date. A holder of Pre-Funded Warrants may not exercise the warrant if the holder, together with its affiliates, would beneficially own more than 19.99 % of the number of the Company’s ordinary shares outstanding or more than 19.99 % of the combined voting power of the Company’s securities outstanding immediately after giving effect to such exercise, unless and until shareholder approval is obtained. Features of the Series A Preferred Shares and Ordinary Shares The Series A preferred shares and ordinary shares have no par value and there is no concept of authorized share capital under Singapore law. The Series A preferred shares are not redeemable and have no entitlement to dividends. Voting The holders of Series A preferred shares are not entitled to vote on any of the matters proposed to shareholders, other than as specified in the Company's Constitution. The holders of ordinary shares are entitled to one vote for each ordinary share held at all meetings of shareholders and written actions in lieu of meetings. Dividends All dividends, if any, shall be declared and paid pro rata according to the number of ordinary shares held by each member entitled to receive dividends. The Company’s board of directors may deduct from any dividend all sums of money presently payable by the member to the Company on account of calls. Liquidation In the event of a liquidation, dissolution or winding up of, or a return of capital by the Company, the ordinary shares will rank equally with the Series A preferred shares after the payment of the liquidation preference of an aggregate of approximately $ 10 thousand for Series A preferred shares.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Share-Based Compensation	7. SHARE-BASED COMPENSATION The Wave Life Sciences Ltd. 2021 Equity Incentive Plan (the “2021 Plan”) was approved by the Company’s shareholders and went into effect on August 10, 2021. The 2021 Plan serves as the successor to the Wave Life Sciences Ltd. 2014 Equity Incentive Plan, as amended (the “2014 Plan”), such that outstanding awards granted under the 2014 Plan continue to be governed by the terms of the 2014 Plan, but no awards may be made under the 2014 Plan after August 10, 2021. The aggregate number of ordinary shares authorized for issuance of awards under the 2021 Plan was originally 5,450,000 ordinary shares, and was subsequently increased to 11,450,000 in August 2022, plus the number of ordinary shares underlying any awards under the 2014 Plan that are forfeited, cancelled or otherwise terminated (other than by exercise or withheld by the Company to satisfy any tax withholding obligation) on or after August 10, 2021. The 2021 Plan authorizes (and the 2014 Plan previously authorized) the board of directors or a committee of the board of directors to, among other things, grant non-qualified share options, restricted awards, which include restricted shares and restricted share units (“RSUs”), and performance awards to eligible employees and directors of the Company. The Company accounts for grants to its board of directors as grants to employees. As of December 31, 2022 , 6,339,480 ordinary shares remained available for future grant under the 2021 Plan. In accordance with Nasdaq Listing Rule 5635(c)(4), the board of directors or a committee of the board may also issue inducement grants outside of the 2021 Plan, material to an individual's entering into employment with the Company. Options and RSUs Share option activity is summarized as follows: Number of Weighted- Weighted- Aggregate (1) Outstanding as of January 1, 2022 6,958,160 $ 10.22 Granted 3,844,242 3.16 Exercised ( 90,000 ) 2.48 Forfeited or cancelled ( 1,030,348 ) 7.90 Outstanding as of December 31, 2022 9,682,054 $ 7.73 7.06 $ 25,032 Options exercisable as of December 31, 2022 4,051,769 $ 13.11 4.77 $ 5,994 (1) The aggregate intrinsic value of options is calculated as the difference between the exercise price of the share options and the fair value of the Company’s ordinary shares for those share options that had exercise prices lower than the fair value of the ordinary shares as of the end of the period. Options generally vest over periods of one to four years , and options that are forfeited or cancelled are available to be granted again. The contractual life of options is generally five or ten years from the grant date. The assumptions used in the Black-Scholes option pricing model to determine the fair value of share options granted to employees during the period were as follows: For the Year Ended December 31, 2022 2021 Risk-free interest rate 1.35 % – 4.23 % 0.42 % – 1.34 % Expected term (in years) 3.0 – 6.1 3.0 – 6.1 Expected volatility 63 % – 96 % 71 % – 86 % Expected dividend yield 0 % 0 % In October 2022, the compensation committee of the Company’s board of directors granted Dr. Verdine, one of the Company’s founders and a member of the Company’s board of directors, a non-qualified share option for 163,467 ordinary shares as form of payment under Dr. Verdine’s consulting agreement for scientific advisory services (as described in Note 13) for the service period of October 1, 2022 through December 31, 2024, the vesting of which is subject to Dr. Verdine’s continued service under the consulting agreement. This was the only non-employee grant made during the year ended December 31, 2022 and there were no options granted to non-employees during the year ended December 31, 2021. The assumptions used in the Black-Scholes option pricing model to determine the fair value of share options granted to non-employees during the period were as follows: Year Ended Risk-free interest rate 4.29 % Expected term (in years) 2.5 Expected volatility 99 % Expected dividend yield 0 % RSU activity for the year ended December 31, 2022 is summarized as follows: RSUs Average Grant Outstanding as of January 1, 2022 1,875,350 $ 13.70 Granted 143,700 2.94 Vested ( 904,891 ) 14.20 Forfeited ( 179,817 ) 17.04 RSUs Outstanding at December 31, 2022 934,342 $ 10.94 RSUs can be time-based or performance-based. Vesting of the performance-based RSUs is contingent on the occurrence of certain regulatory or commercial milestones. In March 2021, the Compensation Committee approved an amendment and restatement of the Company’s outstanding 2019 performance-based RSUs to add an additional milestone to the existing milestones. In 2021, the Company also granted performance-based RSUs with the same terms to certain employees who did not receive the 2019 performance-based RSUs. The Company did not recognize expense in 2021 related to the performance-based RSUs as the related milestones were not considered probable of achievement. In April 2022, the Company determined that a performance-based RSU milestone was achieved and consequently 50 % of the outstanding performance-based RSUs vested, which resulted in the issuance of 384,646 ordinary shares. During the year ended December 31, 2022 , the Company recorded share-based compensation expense of approximately $ 3.8 million, which represents all of the expense related to the achievement of this performance-based RSU milestone. The Company did not recognize any expense related to the other performance-based RSU milestones, as the remaining milestones were not considered probable of achievement as of December 31, 2022. RSUs that are forfeited are available to be granted again. During the year ended December 31, 2022 , 143,700 time-based RSUs were granted to employees. Of the RSUs outstanding at December 31, 2022 , 607,764 are time-based RSUs and 326,578 are performance-based RSUs. Time-based RSUs generally vest over periods of one to four years . As of December 31, 2022 , the unrecognized compensation cost related to outstanding options was $ 9.7 million. The unrecognized compensation cost related to outstanding options is expected to be recognized over a weighted-average period of approximately 2.3 years. For the years ended December 31, 2022 and 2021 , the weighted-average grant date fair value per granted option was $ 2.06 and $ 3.48 , respectively. The aggregate fair value of options that vested during the years ended December 31, 2022 and 2021 was $ 6.9 million and $ 5.7 million, respectively. The unrecognized compensation costs related to outstanding time-based RSUs was $ 1.7 million as of December 31, 2022 , and is expected to be recognized over a weighted-average period of approximately 1.3 years. The total fair value of RSUs vested during the years ended December 31, 2022 and 2021 was $ 1.3 million and $ 1.7 million, respectively. Employee Share Purchase Plan The Wave Life Sciences Ltd. Employee Share Purchase Plan (“ESPP”) allows full-time and certain part-time employees to purchase the Company’s ordinary shares at a discount to fair market value. Eligible employees may enroll in a six-month offering period beginning every January 15 th and July 15 th . Shares are purchased at a price equal to 85 % of the lower of the fair market value of the Company’s ordinary shares on the first business day or the last business day of an offering period. During the years ended December 31, 2022 and 2021 , 166,061 and 92,287 ordinary shares were issued under the ESPP, respectively. As of December 31, 2022 , there were 716,413 ordinary shares available for issuance under the ESPP. Share-Based Compensation Expense Share-based compensation expense for the years ended December 31, 2022 and 2021 is classified as operating expenses in the consolidated statements of operations and comprehensive loss as follows: For the Year Ended December 31, 2022 2021 (in thousands) Research and development expenses $ 7,467 $ 7,267 General and administrative expenses 9,727 9,140 Total share-based compensation expense $ 17,194 $ 16,407 Of the total share-based compensation expense recorded for the year ended December 31, 2022 , less than $ 0.1 million related to non-employee option grants, all of which is included in research and development expenses on the consolidated statements of operations and comprehensive loss. There was no share-based compensation expense recorded for the year ended December 31, 2021 related to options granted to non-employees.

Leases

Leases	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Leases	8. LEASES Lease Arrangements The Company enters into lease arrangements for its facilities. A summary of the arrangements is as follows: Operating Leases Lexington On September 26, 2016, and as amended on December 31, 2016, the Company entered into a 10 year and 9-month lease, which includes two successive five-year renewal options , for its facility in Lexington, Massachusetts, which the Company uses primarily for its current good manufacturing practices (“cGMP”) manufacturing, as well as for additional laboratory and office space. As there is not reasonable certainty that the renewal options will be exercised, the lease liabilities and the right-of-use assets pertaining to the Lexington Lease do not account for the two successive five-year renewal options. Throughout the term of the lease, the Company is responsible for paying certain costs and expenses, in addition to the rent, as specified in the lease, including a proportionate share of applicable taxes, operating expenses and utilities. As required under the terms of the lease agreement, the Company has placed restricted cash of approximately $ 2.7 million in a separate bank account as of December 31, 2022 and 2021. Cambridge In April 2015, the Company entered into a lease agreement for an office and laboratory facility in Cambridge, Massachusetts (the “Cambridge Lease”), which commenced in October 2015 with a term of 7.5 years with a five-year renewal option to extend the lease . Throughout the term of the lease, the Company is responsible for paying certain costs and expenses, in addition to the rent, as specified in the lease, including a proportionate share of applicable taxes, operating expenses and utilities. As required under the terms of the lease agreement, the Company has placed restricted cash of $ 1.0 million in a separate bank account as of December 31, 2022 and 2021. In December 2020, the Company exercised its option under the Cambridge Lease to lease the additional office and laboratory space at the existing facility. The combined space constitutes the entire building. The lease for the additional space commenced on October 1, 2021, with a term of five years and is considered a separate lease from the Cambridge Lease. On the commencement date, the Company utilized the operating lease classification and recorded a right-of-use asset and corresponding operating lease liability of $ 4.5 million and began recognizing straight-line rent expense under ASC 842. Throughout the term of the lease, the Company is responsible for paying certain costs and expenses, in addition to the rent, as specified in the lease, including a proportionate share of applicable taxes, operating expenses and utilities. In June 2022, the Company exercised the five-year renewal option under the Cambridge Lease to extend the lease term through March 2028 (the “Cambridge Lease Extension”). Therefore, as required by ASC 842, the Company calculated an incremental borrowing rate of 10.53 % and remeasured the right-of-use asset and the lease liabilities related to the Cambridge Lease Extension. As a result, an additional $ 12.0 million of operating right-of-use asset and corresponding operating lease liabilities were recorded relating to the Cambridge Lease Extension. The following table contains a summary of the lease costs recognized under ASC 842 and other information pertaining to the Company’s operating leases for the years ended December 31, 2022 and 2021: For the Year Ended December 31, 2022 2021 (in thousands) Lease cost Operating lease cost $ 6,458 $ 4,742 Variable lease cost 2,508 2,150 Total lease cost $ 8,966 $ 6,892 Other information Operating cash flows used for operating leases $ 7,226 $ 6,275 Increase in operating right-of-use assets $ 12,006 $ 4,498 Operating lease liabilities arising from $ 12,006 $ 4,498 Weighted average remaining lease term 5 years 5.5 years Weighted average discount rate 9.2 % 8.4 % Future minimum lease payments under the Company’s non-cancelable operating leases as of December 31, 2022, are as follows: As of December 31, 2022 (in thousands) 2023 $ 8,655 2024 9,311 2025 9,591 2026 9,584 2027 8,987 Thereafter 886 Total lease payments $ 47,014 Less: imputed interest ( 9,400 ) Total operating lease liabilities $ 37,614

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. COMMITMENTS AND CONTINGENCIES Unasserted Claims In the ordinary course of business, the Company may be subject to legal proceedings, claims and litigation as the Company operates in an industry susceptible to patent and other legal claims. The Company accounts for estimated losses with respect to legal proceedings and claims when such losses are probable and estimable. Legal costs associated with these matters are expensed when incurred. The Company is not currently a party to any material legal proceedings.

Net Loss Per Ordinary Share

Net Loss Per Ordinary Share	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Net Loss Per Ordinary Share	10. NET LOSS PER ORDINARY SHARE Basic loss per share is computed by dividing net loss attributable to ordinary shareholders by the weighted-average number of ordinary shares outstanding: Year Ended December 31, 2022 2021 (in thousands except share and per share data) Numerator: Net loss attributable to ordinary shareholders $ ( 161,823 ) $ ( 122,245 ) Denominator: Weighted-average ordinary shares outstanding 78,855,810 51,825,566 Net loss per share, basic and diluted $ ( 2.05 ) $ ( 2.36 ) As of December 31, 2022 , there were 7,093,656 vested and exercisable Pre-Funded Warrants outstanding to purchase ordinary shares for the exercise price of $ 0.0001 per share. The Pre-Funded Warrants are included in the weighted-average shares outstanding used in the calculation of basic net loss per share as the exercise price is negligible and the warrants are fully vested and exercisable. The Company’s potentially dilutive shares, which include outstanding share options to purchase ordinary shares and restricted share units, are considered to be ordinary share equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. The following potential ordinary shares, presented based on amounts outstanding at each period end, were excluded from the calculation of diluted net loss per share attributable to ordinary shareholders for the periods indicated because including them would have had an anti-dilutive effect: As of December 31, 2022 2021 Options to purchase ordinary shares 9,682,054 6,958,160 RSUs 934,342 1,875,350 Series A preferred shares 3,901,348 3,901,348

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	11. INCOME TAXES The components of loss before income taxes were as follows: Year Ended December 31, 2022 2021 (in thousands) Singapore $ ( 8,714 ) $ ( 10,842 ) Rest of world ( 152,428 ) ( 111,607 ) Loss before income taxes $ ( 161,142 ) $ ( 122,449 ) During the years ended December 31, 2022 and 2021, the Company recorded an income tax provision of $ 0.7 million and an income tax benefit of $ 0.2 million, respectively. The income tax provision for the year ended December 31, 2022 was primarily due to the requirement under the Tax Cuts and Jobs Act of 2017 for taxpayers to capitalize and amortize research and development expenditures over five or fifteen years pursuant to Section 174 of the Internal Revenue Code of 1986, as amended (the “Code”), partially offset by the utilization of net operating losses subject to the Section 382 limitation discussed below. The income tax benefit for the year ended December 31, 2021 was primarily due to the release of a portion of the Company’s uncertain tax positions as a result of a lapse in the statute of limitations. The components of the benefit (provision) for income taxes were as follows: Year Ended December 31, 2022 2021 (in thousands) Current benefit (provision) for income taxes: Singapore $ — $ — Rest of world ( 681 ) 204 Total current benefit (provision) for income taxes $ ( 681 ) $ 204 Deferred benefit for income taxes: Singapore $ — $ — Rest of world — — Total deferred benefit (provision) for income taxes $ — $ — Total benefit (provision) for income taxes $ ( 681 ) $ 204 A reconciliation of the Singapore statutory income tax rate to the Company’s effective income tax rate is as follows: Year Ended December 31, 2022 2021 Singapore statutory income tax rate 17.0 % 17.0 % Federal and state tax credits 3.3 5.1 Permanent differences 0.1 ( 2.6 ) Changes in reserves for uncertain tax positions 0.4 ( 2.1 ) Foreign rate differential 8.8 6.3 Tax rate change — 12.5 Other ( 1.0 ) ( 1.1 ) Change in deferred tax asset valuation allowance 7.3 ( 34.9 ) Deferred tax adjustments ( 36.3 ) — Effective income tax rate ( 0.4 )% 0.2 % The components of the Company’s deferred tax assets and liabilities as of December 31, 2022 and 2021 are as follows: December 31, 2022 2021 (in thousands) Deferred tax assets: Net operating loss carryforwards $ 158,413 $ 170,997 Federal and state tax credits 368 40,163 Share-based compensation 7,265 7,194 Accumulated amortization 782 872 Operating lease liabilities 10,276 8,173 Deferred revenue 16,786 13,546 Capitalized research and development 36,643 — Other 3,164 2,351 Total deferred tax assets 233,697 243,296 Valuation allowance ( 226,273 ) ( 238,170 ) Net deferred tax assets 7,424 5,126 Deferred tax liabilities: Operating lease right-of-use assets ( 7,333 ) ( 5,021 ) Accumulated depreciation ( 86 ) ( 98 ) Other ( 5 ) ( 7 ) Total deferred tax liabilities ( 7,424 ) ( 5,126 ) Net deferred tax assets (liabilities) $ — $ — A roll-forward of the valuation allowance for the years ended December 31, 2022 and 2021 is as follows: Year Ended December 31, 2022 2021 (in thousands) Balance at beginning of year $ 238,170 $ 195,381 Increase in valuation allowance 3,134 42,886 Decrease in valuation allowance ( 14,934 ) — Effect of foreign currency translation ( 97 ) ( 97 ) Balance at end of year $ 226,273 $ 238,170 As of December 31, 2022 , the Company had federal net operating loss carryforwards in the United States of $ 272.4 million, of which $ 271.6 million may be available to offset future income tax liabilities indefinitely, while $ 0.8 million of carryforwards that were in existence as of December 31, 2017 may offset future income tax liabilities up through 2037 . As of December 31, 2022 , the Company had state net operating loss carryforwards of $ 43.9 million that will begin to expire in 2038 . As of December 31, 2022 and 2021 , the Company had U.S. federal research and development tax credit carryforwards of approximately $ 0.2 million and $ 12.8 million, respectively, available to offset future U.S. federal income taxes and will begin to expire in 2042 . As of December 31, 2022 and 2021 , the Company had state research and development tax credit carryforwards of approximately $ 0.2 million and $ 9.1 million, respectively, available to offset future state income taxes and will begin to expire in 2037 , and no longer had state investment tax credit carryforwards. As of December 31, 2022 , the Company no longer had a U.S. orphan drug credit carryforward. As of December 31, 2022 and 2021 , the Company had net operating loss carryforwards in Japan of $ 2.3 million and $ 2.7 million, respectively, which may be available to offset future income tax liabilities and begin to expire in 2023 . As of December 31, 2022 and 2021 , the Company had net operating loss carryforwards in Singapore of $ 111.2 million and $ 189.2 million, respectively, which may be available to offset future income tax liabilities and can be carried forward indefinitely. As of December 31, 2022 and 2021 , the Company had net operating loss carryforwards in the United Kingdom of $ 314.5 million and $ 254.3 million, respectively, which may be available to offset future income tax liabilities and can be carried forward indefinitely. The Company has evaluated the positive and negative evidence bearing upon its ability to realize its deferred tax assets. As of December 31, 2022, management has considered the Company’s history of cumulative net losses incurred since inception and its lack of commercialization of any products or generation of any revenue from product sales since inception and has concluded that it is more likely than not that the Company will not realize the benefits of the deferred tax assets in all jurisdictions. Accordingly, a full valuation allowance has been established against those deferred tax assets as of December 31, 2022. The valuation allowance decreased by approximately $ 11.9 million in 2022. The decrease in the valuation allowance for 2022 was primarily a result of the 2022 Section 382 limitation on the Company's utilization of its federal and state tax credits and state net operating losses before their expiration. The Company may release this valuation allowance when management determines that it is more-likely-than-not that the deferred tax assets will be realized. Any release of valuation allowance will be recorded as a tax benefit either increasing net income or decreasing net loss. The Company’s reserves related to taxes and its accounting for uncertain tax positions are based on a determination of whether and how much of a tax benefit taken by the Company in its tax filings or positions is more-likely-than-not to be realized following resolution of any potential contingencies present related to the tax benefit. A summary of activity in the Company’s unrecognized tax benefits is as follows: 2022 2021 (in thousands) Unrecognized tax benefit at the beginning of the year $ 19,864 $ 18,416 Tax positions related to prior years ( 7,320 ) ( 56 ) Tax positions related to statute lapse — ( 575 ) Tax positions related to the current year 1,401 2,079 Unrecognized tax benefit at the end of the year $ 13,945 $ 19,864 As of December 31, 2022 and 2021 , the total amount of gross unrecognized tax benefits, which excludes interest and penalties, was $ 13.9 million and $ 19.9 million, respectively. At December 31, 2022 , $ 0.2 million of the net unrecognized tax benefits would affect the Company’s annual effective tax rate if recognized. The Company files income tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company is subject to examination by various tax authorities in the United States, Japan, Singapore and the United Kingdom. Tax years from 2019 to the present are still open to examination in the United States, from 2017 to the present in Japan, from 2018 to the present in Singapore and from 2021 to the present in the United Kingdom. To the extent that the Company has tax attribute carryforwards, the tax years in which the attribute was generated may still be adjusted upon examination by the tax authorities to the extent utilized in a future period. In October 2022, the Inland Revenue Authority of Singapore (“IRAS”) completed its examination of the Company’s corporate income tax returns for the 2016 and 2017 tax years. The Company received notice of adjustments from IRAS indicating that certain R&D expenses are temporarily disallowed until the Company recognizes income related to the R&D initiatives. As a result of the final assessments made by IRAS, the Company reclassified $ 14.9 million of its net operating loss carryforward deferred tax assets to capitalized research and development deferred tax assets that remained subject to a full valuation allowance. As of December 31, 2022 and 2021 , $ 44.1 million and $ 21.1 million, respectively, of cash and cash equivalents were held by the subsidiaries outside of Singapore. The Company does not provide for Singapore income tax or foreign withholding taxes on foreign unrepatriated earnings, as the Company intends to permanently reinvest undistributed earnings in its foreign subsidiaries. If the Company decides to change this assertion in the future to repatriate any additional foreign earnings, the Company may be required to accrue and pay taxes. Because of the complexity of Singapore and foreign tax rules applicable to the distribution of earnings from foreign subsidiaries to Singapore, the determination of the unrecognized deferred tax liability on these earnings is not practicable. Utilization of the net operating loss carryforwards and research and development tax credit carryforwards in the United States may be subject to a substantial annual limitation under Section 382 of the Code, due to ownership changes that have occurred previously or that could occur in the future. These ownership changes may limit the amount of carryforwards that can be utilized annually to offset future taxable income. In general, an ownership change, as defined by Section 382, results from transactions increasing the ownership of certain shareholders or public groups in the shares of a corporation by more than 50% over a three-year period. In 2018, 2020 and 2022, the Company completed studies to assess whether an ownership change had occurred or whether there have been multiple ownership changes since its formation. The results of the 2018 study indicated that the Company experienced an ownership change as defined by Section 382 of the Code. Based on the results of the 2018 study, management had determined that the limitations will not have a material impact on the Company’s ability to utilize its net operating losses and research and development credit carryforwards to offset future tax liabilities. The results of the 2020 study indicated that the Company did not experience an ownership change since the 2018 study. The results of the 2022 study indicated that the Company experienced an ownership change and will be limited in its ability to utilize net operating losses and its research and development credit carryforwards in the 2022 tax year and going forward. Based on the 2022 study, $ 46.8 million of federal and state tax credits and $ 218.2 million of state net operating losses will expire unutilized. Should one or more ownership changes occur in the future, the Company’s ability to utilize its net operating losses and research and development credit carryforwards may be further limited.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2022
Postemployment Benefits [Abstract]
Employee Benefit Plans	12. EMPLOYEE BENEFIT PLANS The Company has a 401(k) retirement and savings plan (the “401(k) Plan”) covering employees of Wave USA. The 401(k) Plan allows employees to make contributions up to the maximum allowable amount set by the Internal Revenue Service. Under the 401(k) Plan, the Company may make discretionary contributions as approved by the board of directors. The Company made contributions of $ 1.1 million and $ 1.0 million in the years ended December 31, 2022 and 2021 , respectively.

Related Parties

Related Parties	12 Months Ended
	Dec. 31, 2022
Related Party Transactions [Abstract]
Related Parties	13. RELATED PARTIES The Company had the following related party transactions for the periods presented in the accompanying consolidated financial statements: • In 2012, the Company entered into a consulting agreement for scientific advisory services with Dr. Gregory L. Verdine, one of the Company’s founders and a member of the Company’s board of directors. The consulting agreement does not have a specific term and may be terminated by either party upon 14 days ’ prior written notice. Pursuant to the consulting agreement, the Company pays Dr. Verdine approximately $ 13 thousand per month, plus reimbursement for certain expenses. In October 2022, the compensation committee of the Company’s board of directors granted Dr. Verdine a non-qualified share option for 163,467 ordinary shares as form of payment under this consulting agreement for the service period of October 1, 2022 through December 31, 2024, the vesting of which is subject to Dr. Verdine’s continued service under the consulting agreement.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	14. SUBSEQUENT EVENTS GSK Collaboration Agreement and GSK Equity Investment On December 13, 2022, Wave USA and Wave UK entered into a Collaboration and License Agreement (the “GSK Collaboration Agreement”) with GlaxoSmithKline Intellectual Property (No. 3) (“GSK”). Pursuant to the GSK Collaboration Agreement, Wave and GSK have agreed to collaborate on the research, development, and commercialization of oligonucleotide therapeutics, including an exclusive global license to WVE-006. The discovery collaboration has an initial four-year research term and combines Wave’s proprietary discovery and drug development platform, PRISM, with GSK’s unique insights from human genetics and its global development and commercial capabilities. The GSK Collaboration Agreement became effective as of January 27, 2023, following the completion of customary closing conditions. In connection with the parties’ entry into the GSK Collaboration Agreement, Wave entered into a share purchase agreement on December 13, 2022 with Glaxo Group Limited (“GGL”), an affiliate of GSK, pursuant to which Wave agreed to sell to GGL 10,683,761 of its ordinary shares at a purchase price of $ 4.68 per share (the “GSK Equity Investment”). The GSK Equity Investment closed on January 26, 2023, following the completion of customary closing conditions. Subsequent to December 31, 2022 and in respect to the above referenced transactions, Wave received $ 170.0 million in cash, of which $ 120.0 million was an upfront payment under the GSK Collaboration Agreement and $ 50.0 million was the GSK Equity Investment.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid securities with maturities of three months or less from the date of purchase to be cash equivalents. The Company's cash and cash equivalents are comprised of funds held in checking and money market accounts.
Short-Term Investments	Short-Term Investments The Company’s short-term investments consist of term deposits.
Principles of Consolidation	Principles of Consolidation The Company’s consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. 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 consolidated financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include the assumptions used to determine the fair value of share-based awards, the Company’s revenue recognition policy, particularly, (a) assessing the number of performance obligations; (b) determining the transaction price; (c) allocating the transaction price to the performance obligations in the contract; and (d) determining the pattern over which performance obligations are satisfied, including estimates to complete performance obligations, the evaluation of progress to completion of external research and development costs which can result in prepaid or accrued expenses related to the Company’s contract research organizations (“CROs”) and contract manufacturing organizations (“CMOs”), the valuation allowance required for the Company’s deferred tax assets, determining uncertain tax positions and the related liabilities, and estimating refundable tax credits. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Actual results could differ from the Company’s estimates.
Segment Data	Segment Data The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The Company’s singular focus is on developing its proprietary discovery and drug development platform, PRISM, to develop and commercialize a broad pipeline of nucleic acid-based therapeutics, or oligonucleotides.
Going Concern	Going Concern At each reporting period, the Company evaluates whether there are conditions or events that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the financial statements are issued. The Company is required to make certain additional disclosures if the Company concludes substantial doubt exists and it is not alleviated by the Company’s plans or when the Company’s plans alleviate substantial doubt about the Company’s ability to continue as a going concern. The Company’s evaluation entails analyzing prospective operating budgets and forecasts for expectations of the Company’s cash needs and comparing those needs to the current cash and cash equivalent balance.
Foreign Currency Translation	Foreign Currency Translation The functional currency is the U.S. dollar for all of the Company’s entities aside from Wave Japan, which has the Japanese Yen as its functional currency. Assets and liabilities of Wave Japan are translated at period end exchange rates while revenues and expenses of Wave Japan are translated at average exchange rates for the period. Net unrealized gains and losses from foreign currency translation are reflected as other comprehensive income (loss) within the consolidated statements of Series A preferred shares and shareholders’ equity (deficit) and the consolidated statements of operations and comprehensive loss. Gains and losses on foreign currency transactions are included in the consolidated statements of operations and comprehensive loss within other income, net.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. The fair value hierarchy is a hierarchy of inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the financial instrument based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the financial instrument and are developed based on the information available in the circumstances. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value of the investments and is not a measure of the investment credit quality. The hierarchy defines three levels of valuation inputs: Level 1—Unadjusted quoted prices in active markets that are accessible at the measurement date of identical, unrestricted assets. Level 2—Quoted prices for similar assets, or inputs that are observable, either directly or indirectly, for substantially the full term through corroboration with observable market data. Level 2 includes investments valued at quoted prices adjusted for legal or contractual restrictions specific to the security. Level 3—Pricing inputs are unobservable for the asset, that is, inputs that reflect the reporting entity’s own assumptions about the assumptions market participants would use in pricing the asset. Level 3 includes private investments that are supported by little or no market activity. Cash, cash equivalents and restricted cash are Level 1 assets which are comprised of funds held in checking and money market accounts. Short-term investments are Level 2 assets which are comprised of term deposits. Cash, cash equivalents and restricted cash were recorded at fair value as of December 31, 2022 and 2021, totaling $ 92.2 million and $ 154.2 million, respectively. There were no short-term investments as of December 31, 2022 or 2021 , as the $ 75.0 million of term deposits that constitute the Company’s short-term investments were all purchased and reached maturity during the twelve months ended December 31, 2022 . The carrying amounts of accounts payable and accrued expenses approximate their fair values due to their short-term maturities.
Concentration of Credit Risk	Concentration of Credit Risk Cash, cash equivalents, restricted cash and short-term investments are financial instruments that potentially subject the Company to concentration of credit risk. The Company uses several financial institutions to maintain its cash, cash equivalents, restricted cash and short-term investments, all of which are high quality, accredited financial institutions and, accordingly, such funds are subject to minimal credit risk. The Company has not experienced any losses in such accounts and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company has no financial instruments with off-balance sheet risk of loss.
Restricted Cash	Restricted Cash Restricted cash consists primarily of cash placed in separate restricted bank accounts as required under the terms of the Company’s lease agreements for its Cambridge, Massachusetts and Lexington, Massachusetts facilities (refer to Note 8). As of December 31, 2022 and 2021 , the Company had $ 3.7 million of restricted cash, of which $ 2.7 million related to the Lexington facility and $ 1.0 million related to the Cambridge facility.
Property and Equipment	Property and Equipment Property and equipment, which consists primarily of equipment, furniture, software and leasehold improvements, are stated at cost less accumulated depreciation. Depreciation is calculated on a straight-line basis over the following estimated useful lives of the assets: Equipment, Furniture and Software 3 - 7 years Leasehold Improvements Shorter of asset life or lease term Depreciation begins at the time the asset is placed in service. Maintenance and repairs are charged to operations as incurred. Upon retirement or sale, the cost of the disposed asset and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is reflected in the consolidated statements of operations and comprehensive loss.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets consist of property and equipment. Long-lived assets are reviewed for impairment whenever events or other changes in circumstances indicate that the carrying amount may not be recoverable. Certain factors may exist or events may occur that indicate that impairment exists including, but not limited to, the following: significant underperformance relative to historical or projected future operating results; significant changes in the manner of use of the underlying assets; and significant adverse industry or market economic trends. When performing the impairment assessment for long-lived assets, the Company compares the carrying value of such assets to the estimated undiscounted future net cash flows expected from the use of the assets and their eventual disposition. In the event that the carrying value of the assets is determined to be unrecoverable, the Company would estimate the fair value of the assets and record an impairment charge for the excess of the carrying value over the fair value.
Revenue Recognition	Revenue Recognition The Company recognizes revenue in accordance with Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers (“ASC 606”). This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, and financial instruments. Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five-step analysis: (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 in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step analysis to contracts when it is probable that the entity will collect the consideration to which it is entitled 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 each contract, determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. The Company has entered into collaboration agreements for research, development, and commercial services, under which the Company licenses certain rights to its product candidates to third parties. The terms of these arrangements typically include payment to the Company of one or more of the following: non-refundable, upfront license fees; reimbursement of certain costs; customer option exercise fees; development, regulatory and commercial milestone payments; and royalties on net sales of licensed products. Any variable consideration is constrained and, therefore, the cumulative revenue associated with this consideration is not recognized until it is deemed not to be at significant risk of reversal. In determining the appropriate amount of revenue to be recognized as the Company fulfills its obligations under each of its agreements for which the collaboration partner is also a customer, the Company performs the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations, including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. As part of the accounting for these arrangements, the Company must use significant judgment to determine: (a) the number of performance obligations based on the determination under step (ii) above; (b) the transaction price under step (iii) above; and (c) the timing of satisfaction of performance obligations as a measure of progress in step (v) above. The Company uses significant judgment to determine whether milestones or other variable consideration, except for royalties, should be included in the transaction price as described further below. The transaction price is allocated to the optional goods and services the Company expects to provide. The Company uses estimates to determine the timing of satisfaction of performance obligations. Amounts received prior to being recognized as revenue are recorded as deferred revenue. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as current portion of deferred revenue in the accompanying consolidated balance sheets. 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. Licenses of intellectual property: In assessing whether a promise or performance obligation is distinct from the other promises, the Company considers factors such as the research, development, manufacturing and commercialization capabilities of the customer and the availability of the associated expertise in the general marketplace. In addition, the Company considers whether the customer can benefit from a promise for its intended purpose without the receipt of the remaining promise, whether the value of the promise is dependent on the unsatisfied promise, whether there are other vendors that could provide the remaining promise, and whether it is separately identifiable from the remaining promise. For licenses that are combined 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. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Research and development services : If an arrangement is determined to contain a promise or obligation for the Company to perform research and development services, the Company must determine whether these services are distinct from other promises in the arrangement. In assessing whether the services are distinct from the other promises, the Company considers the capabilities of the customer to perform these same services. In addition, the Company considers whether the customer can benefit from a promise for its intended purpose without the receipt of the remaining promise, whether the value of the promise is dependent on the unsatisfied promise, whether there are other vendors that could provide the remaining promise, and whether it is separately identifiable from the remaining promise. For research and development services that are combined 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. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Customer options: If an arrangement is determined to contain customer options that allow the customer to acquire additional goods or services, the goods and services underlying the customer options are not considered to be performance obligations at the outset of the arrangement, as they are contingent upon option exercise. The Company evaluates the customer options for material rights, that is, the option to acquire additional goods or services for free or at a discount. If the customer options are determined to represent a material right, the material right is recognized as a separate performance obligation at the outset of the arrangement. The Company allocates the transaction price to material rights based on the standalone selling price. As a practical alternative to estimating the standalone selling price when the goods or services are both (i) similar to the original goods and services in the contract and (ii) provided in accordance with the terms of the original contract, the Company allocates the total amount of consideration expected to be received from the customer to the total goods or services expected to be provided to the customer. Amounts allocated to any material right are not recognized as revenue until the option is exercised and the performance obligation is satisfied. Milestone payments: At the inception of each arrangement that includes milestone payments, the Company evaluates whether a significant reversal of cumulative revenue provided in conjunction with achieving the milestones is probable, and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant reversal of cumulative revenue would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. For other milestones, the Company evaluates factors such as the scientific, clinical, regulatory, commercial, and other risks that must be overcome to achieve the particular milestone in making this assessment. There is considerable judgment involved in determining whether it is probable that a significant reversal of cumulative revenue would not occur. At the end of each subsequent reporting period, the Company reevaluates the probability of achievement of all milestones subject to constraint and, if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment. Royalties: For arrangements that include sales-based royalties, including milestone payments based on a level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes 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). To date, the Company has not recognized any royalty revenue resulting from any of its licensing arrangements. Contract costs : The Company recognizes as an asset the incremental costs of obtaining a contract with a customer if the costs are expected to be recovered. As a practical expedient, the Company recognizes the incremental costs of obtaining a contract as an expense when incurred if the amortization period of the asset that it otherwise would have recognized is one year or less. To date, the Company has not incurred any incremental costs of obtaining a contract with a customer.
Research and Development Expenses	Research and Development Expenses Research and development expenses are expensed as incurred. External development costs are recognized based on an evaluation of the progress to completion of specific tasks. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in the accompanying consolidated balance sheets as prepaid or accrued expenses.
License Agreements and Patent Costs	License Agreements and Patent Costs Costs associated with licenses of technology and patent costs are expensed as incurred and are generally included in research and development expense in the consolidated statements of operations and comprehensive loss.
Refundable Tax Credits	Refundable Tax Credits The Company is eligible for refundable tax credits with tax authorities for certain qualified operating expenses. The Company recognizes refundable tax credits when there is reasonable assurance that the Company will comply with the requirements of the refundable tax credit and that the refundable tax credit will be received. Refundable tax credits are recorded as income and classified in other income, net in the consolidated statements of operations and comprehensive loss.
Net Loss per Share	Net Loss per Share Basic net loss per share is computed using the weighted-average number of ordinary shares outstanding during the period. The outstanding Pre-Funded Warrants (as defined in note 6) are included in the weighted-average number of ordinary shares outstanding used in the calculation of basic net loss per share as the exercise price is negligible and the warrants are fully vested and exercisable. Diluted net loss per share is computed using the sum of the weighted-average number of ordinary shares outstanding during the period and, if dilutive, the weighted-average number of potential ordinary shares, including the assumed exercise of share options and the assumed vesting of RSUs (as defined in note 7). The Company applies the two-class method to calculate its basic and diluted net loss per share attributable to ordinary shareholders, as its Series A preferred shares are participating securities. The two-class method is an earnings allocation formula that treats a participating security as having rights to earnings that otherwise would have been available to ordinary shareholders. However, for the periods presented, the two-class method does not impact the net loss per ordinary share as the Company was in a net loss position for each of the periods presented and holders of Series A preferred shares do not participate in losses. The Company’s Series A preferred shares contractually entitle the holders of such shares to participate in dividends but do not contractually require the holders of such shares to participate in losses of the Company. Accordingly, for periods in which the Company reports a net loss attributable to ordinary shareholders, diluted net loss per share attributable to ordinary shareholders is the same as basic net loss per share attributable to ordinary shareholders, since dilutive ordinary shares are not assumed to have been issued if their effect is anti-dilutive.
Share-Based Compensation	Share-Based Compensation The Company measures and recognizes share-based compensation expense, for both employee and director option awards, based on the grant date fair value of the awards. The Company calculates the fair value of restricted share unit awards based on the grant date fair value of the underlying ordinary shares. The Company determines the fair value of share-based awards granted to non-employees as either the fair value of the consideration received or the fair value of the equity instruments issued, whichever is more reliably measurable. Equity instruments issued to non-employees as consideration for goods or services received by the Company have been accounted for based on the fair value of the equity instruments issued. The Company recognizes share-based compensation expense on a straight-line basis over the requisite service period of the awards, which is generally the vesting period. The Company accounts for forfeitures as they occur. The Company classifies share-based compensation expense in its consolidated statements of operations and comprehensive loss in the same manner in which the award recipient’s compensation costs are classified or in which the award recipient’s service payments are classified. The fair value of each share option grant was determined using the methods and assumptions discussed below. These inputs are generally subjective and require significant judgment and estimation by management. • Fair Value of Ordinary Shares The fair value of the ordinary shares underlying the Company’s share-based awards is based on the closing price of the Company’s ordinary shares as reported by the Nasdaq Global Market on the date of grant. • Expected Term The expected term of share options represents the weighted-average period that the share options are expected to remain outstanding. The Company estimated the expected term using the simplified method, which is an average of the contractual term of the option and the vesting period. • Expected Volatility Since there was limited historical data for the Company’s ordinary shares and limited company-specific historical volatility through the third quarter of 2021, the Company determined the share price volatility for options granted based on an analysis of the volatility used by a peer group of publicly traded companies. In evaluating similarity, the Company considers factors such as industry, stage of life cycle and size. Beginning in the fourth quarter of 2021, the Company had sufficient historical volatility data for its ordinary shares and as such no longer relies on an analysis of the volatility from a peer group to calculate expected volatility. • Risk-free Interest Rate The risk-free interest rate is based on the U.S. Treasury yield in effect at the time of the grant for zero-coupon U.S. Treasury notes with remaining terms similar to the expected term of the options. • Dividend Rate The expected dividend was assumed to be zero as the Company has never paid dividends and has no current plans to do so.
Income Taxes	Income Taxes The Company accounts for income taxes using an asset and liability approach, which requires recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the consolidated financial statements but have not been reflected in taxable income. A valuation allowance is established to reduce deferred tax assets to their estimated realizable value. Therefore, the Company provides a valuation allowance to the extent that it is more likely than not that all or a portion of the deferred tax assets will not be realized in the future. The Company accounts for uncertainty in income taxes recognized in the financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the tax authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50 % likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties. The Company recognizes interest and penalties related to uncertain tax positions in the income tax provision on the consolidated statements of operations and comprehensive loss. The Company has certain service arrangements in place between its U.S., Japan, U.K. and Singapore entities, which include transfer pricing assumptions. The determination of the appropriate level of transfer pricing requires judgment based on transfer pricing analyses of comparable companies. The Company monitors the nature of its service arrangements for changes in its operations as well as economic conditions. The Company also periodically reviews the transfer pricing analyses for changes in the composition in the pool of comparable companies as well as the related ongoing results of the comparable companies.
Leases	Leases The Company accounts for leases in accordance with ASC Topic 842, Leases (“ASC 842”). At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present in the arrangement. Most leases with a term greater than one year are recognized on the balance sheet as right-of-use assets and short-term and long-term lease liabilities, as applicable. The Company typically only includes an initial lease term in its assessment of a lease arrangement. Options to renew a lease are not included in the Company’s assessment unless there is reasonable certainty that the Company will renew the lease. The Company monitors its plans to renew its leases on a quarterly basis. Certain lease agreements include rental payments that are adjusted periodically for inflation or other variables. In addition to rent, the leases may require the Company to pay additional amounts for taxes, insurance, maintenance, or other expenses, which are generally referred to as non-lease components. Such adjustments to rental payments and variable non-lease components are treated as variable lease payments and recognized in the period in which the obligation for these payments are incurred. Variable lease components and variable non-lease components are not measured as part of the right-of-use asset and lease liability. Only when lease components and their associated non-lease components are fixed are they accounted for as a single lease component and are recognized as part of a right-of-use asset and lease liability. Total contract consideration is allocated to the combined fixed lease and non-lease component. This policy election applies consistently to all asset classes under lease agreements. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected remaining lease term. Certain adjustments to the right-of-use asset may be required for items such as incentives received. The interest rate implicit in lease contracts is typically not readily determinable. As a result, the Company utilizes its incremental borrowing rate, which reflects the fixed rate at which the Company could borrow on a collateralized basis the amount of the lease payments in the same currency, for a similar term, in a similar economic environment.
Accounting Pronouncements	Accounting Pronouncements There were no recently issued or adopted accounting pronouncements that would have a material impact on the Company's consolidated financial statements.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Schedule of Estimated Useful Life of Assets	Depreciation is calculated on a straight-line basis over the following estimated useful lives of the assets: Equipment, Furniture and Software 3 - 7 years Leasehold Improvements Shorter of asset life or lease term

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net, consists of the following: December 31, 2022 2021 (in thousands) Furniture and equipment $ 25,509 $ 25,657 Software 890 817 Leasehold improvements 28,413 27,994 Fixed assets in progress 318 28 Total 55,130 54,496 Less accumulated depreciation ( 37,846 ) ( 32,230 ) Property and equipment, net $ 17,284 $ 22,266

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2022
Payables and Accruals [Abstract]
Summary of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following: December 31, 2022 2021 (in thousands) Accrued compensation $ 12,287 $ 10,181 Accrued expenses related to CROs and CMOs 3,516 3,571 Accrued expenses and other current liabilities 1,749 1,109 Total accrued expenses and other current liabilities $ 17,552 $ 14,861

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2022
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Summary of Share Option Activity	Share option activity is summarized as follows: Number of Weighted- Weighted- Aggregate (1) Outstanding as of January 1, 2022 6,958,160 $ 10.22 Granted 3,844,242 3.16 Exercised ( 90,000 ) 2.48 Forfeited or cancelled ( 1,030,348 ) 7.90 Outstanding as of December 31, 2022 9,682,054 $ 7.73 7.06 $ 25,032 Options exercisable as of December 31, 2022 4,051,769 $ 13.11 4.77 $ 5,994 (1) The aggregate intrinsic value of options is calculated as the difference between the exercise price of the share options and the fair value of the Company’s ordinary shares for those share options that had exercise prices lower than the fair value of the ordinary shares as of the end of the period.
Summary of RSU Activity	RSU activity for the year ended December 31, 2022 is summarized as follows: RSUs Average Grant Outstanding as of January 1, 2022 1,875,350 $ 13.70 Granted 143,700 2.94 Vested ( 904,891 ) 14.20 Forfeited ( 179,817 ) 17.04 RSUs Outstanding at December 31, 2022 934,342 $ 10.94
Summary of Share-based Compensation Expense Classified in Consolidated Statements of Operations and Comprehensive Loss	Share-based compensation expense for the years ended December 31, 2022 and 2021 is classified as operating expenses in the consolidated statements of operations and comprehensive loss as follows: For the Year Ended December 31, 2022 2021 (in thousands) Research and development expenses $ 7,467 $ 7,267 General and administrative expenses 9,727 9,140 Total share-based compensation expense $ 17,194 $ 16,407 Of the total share-based compensation expense recorded for the year ended December 31, 2022 , less than $ 0.1 million related to non-employee option grants, all of which is included in research and development expenses on the consolidated statements of operations and comprehensive loss. There was no share-based compensation expense recorded for the year ended December 31, 2021 related to options granted to non-employees.
Employee Stock Option [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Summary of Fair Value of Share Options Granted	The assumptions used in the Black-Scholes option pricing model to determine the fair value of share options granted to employees during the period were as follows: For the Year Ended December 31, 2022 2021 Risk-free interest rate 1.35 % – 4.23 % 0.42 % – 1.34 % Expected term (in years) 3.0 – 6.1 3.0 – 6.1 Expected volatility 63 % – 96 % 71 % – 86 % Expected dividend yield 0 % 0 % The assumptions used in the Black-Scholes option pricing model to determine the fair value of share options granted to non-employees during the period were as follows: Year Ended Risk-free interest rate 4.29 % Expected term (in years) 2.5 Expected volatility 99 % Expected dividend yield 0 %

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Summary of Lease Costs Recognized and Other Information Pertaining to Operating Leases	The following table contains a summary of the lease costs recognized under ASC 842 and other information pertaining to the Company’s operating leases for the years ended December 31, 2022 and 2021: For the Year Ended December 31, 2022 2021 (in thousands) Lease cost Operating lease cost $ 6,458 $ 4,742 Variable lease cost 2,508 2,150 Total lease cost $ 8,966 $ 6,892 Other information Operating cash flows used for operating leases $ 7,226 $ 6,275 Increase in operating right-of-use assets $ 12,006 $ 4,498 Operating lease liabilities arising from $ 12,006 $ 4,498 Weighted average remaining lease term 5 years 5.5 years Weighted average discount rate 9.2 % 8.4 %
Schedule of Future Minimum Rental Payments for Operating Leases Under Topic 842	Future minimum lease payments under the Company’s non-cancelable operating leases as of December 31, 2022, are as follows: As of December 31, 2022 (in thousands) 2023 $ 8,655 2024 9,311 2025 9,591 2026 9,584 2027 8,987 Thereafter 886 Total lease payments $ 47,014 Less: imputed interest ( 9,400 ) Total operating lease liabilities $ 37,614

Net Loss Per Ordinary Share (Ta

Net Loss Per Ordinary Share (Tables)	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Summary of Basic and Diluted Net Loss Per Ordinary Share Outstanding	Basic loss per share is computed by dividing net loss attributable to ordinary shareholders by the weighted-average number of ordinary shares outstanding: Year Ended December 31, 2022 2021 (in thousands except share and per share data) Numerator: Net loss attributable to ordinary shareholders $ ( 161,823 ) $ ( 122,245 ) Denominator: Weighted-average ordinary shares outstanding 78,855,810 51,825,566 Net loss per share, basic and diluted $ ( 2.05 ) $ ( 2.36 )
Anti-Dilutive Shares Excluded from Calculation of Diluted Net Loss Per Ordinary Share	The following potential ordinary shares, presented based on amounts outstanding at each period end, were excluded from the calculation of diluted net loss per share attributable to ordinary shareholders for the periods indicated because including them would have had an anti-dilutive effect: As of December 31, 2022 2021 Options to purchase ordinary shares 9,682,054 6,958,160 RSUs 934,342 1,875,350 Series A preferred shares 3,901,348 3,901,348

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Components of Loss before Income Taxes	The components of loss before income taxes were as follows: Year Ended December 31, 2022 2021 (in thousands) Singapore $ ( 8,714 ) $ ( 10,842 ) Rest of world ( 152,428 ) ( 111,607 ) Loss before income taxes $ ( 161,142 ) $ ( 122,449 )
Deferred Components of Benefit (Provision), Net for Income Taxes	The components of the benefit (provision) for income taxes were as follows: Year Ended December 31, 2022 2021 (in thousands) Current benefit (provision) for income taxes: Singapore $ — $ — Rest of world ( 681 ) 204 Total current benefit (provision) for income taxes $ ( 681 ) $ 204 Deferred benefit for income taxes: Singapore $ — $ — Rest of world — — Total deferred benefit (provision) for income taxes $ — $ — Total benefit (provision) for income taxes $ ( 681 ) $ 204
Components of Deferred Tax Assets and Liabilities	The components of the Company’s deferred tax assets and liabilities as of December 31, 2022 and 2021 are as follows: December 31, 2022 2021 (in thousands) Deferred tax assets: Net operating loss carryforwards $ 158,413 $ 170,997 Federal and state tax credits 368 40,163 Share-based compensation 7,265 7,194 Accumulated amortization 782 872 Operating lease liabilities 10,276 8,173 Deferred revenue 16,786 13,546 Capitalized research and development 36,643 — Other 3,164 2,351 Total deferred tax assets 233,697 243,296 Valuation allowance ( 226,273 ) ( 238,170 ) Net deferred tax assets 7,424 5,126 Deferred tax liabilities: Operating lease right-of-use assets ( 7,333 ) ( 5,021 ) Accumulated depreciation ( 86 ) ( 98 ) Other ( 5 ) ( 7 ) Total deferred tax liabilities ( 7,424 ) ( 5,126 ) Net deferred tax assets (liabilities) $ — $ —
Summary of Valuation Allowance	A roll-forward of the valuation allowance for the years ended December 31, 2022 and 2021 is as follows: Year Ended December 31, 2022 2021 (in thousands) Balance at beginning of year $ 238,170 $ 195,381 Increase in valuation allowance 3,134 42,886 Decrease in valuation allowance ( 14,934 ) — Effect of foreign currency translation ( 97 ) ( 97 ) Balance at end of year $ 226,273 $ 238,170
Summary of Activity in Unrecognized Tax Benefits	A summary of activity in the Company’s unrecognized tax benefits is as follows: 2022 2021 (in thousands) Unrecognized tax benefit at the beginning of the year $ 19,864 $ 18,416 Tax positions related to prior years ( 7,320 ) ( 56 ) Tax positions related to statute lapse — ( 575 ) Tax positions related to the current year 1,401 2,079 Unrecognized tax benefit at the end of the year $ 13,945 $ 19,864
Singapore [Member]
Reconciliation of Statutory Income Tax Rate	A reconciliation of the Singapore statutory income tax rate to the Company’s effective income tax rate is as follows: Year Ended December 31, 2022 2021 Singapore statutory income tax rate 17.0 % 17.0 % Federal and state tax credits 3.3 5.1 Permanent differences 0.1 ( 2.6 ) Changes in reserves for uncertain tax positions 0.4 ( 2.1 ) Foreign rate differential 8.8 6.3 Tax rate change — 12.5 Other ( 1.0 ) ( 1.1 ) Change in deferred tax asset valuation allowance 7.3 ( 34.9 ) Deferred tax adjustments ( 36.3 ) — Effective income tax rate ( 0.4 )% 0.2 %

The Company - Additional Inform

The Company - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2023	Dec. 31, 2022	Dec. 31, 2021
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cash and cash equivalents		$ 88,497	$ 150,564
Net proceeds from sale of ordinary shares		$ 51,220
Subsequent Event [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Proceeds from collaboration and share purchase agreement	$ 170,000
Subsequent Event [Member] | GSK Equity Investment [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Net proceeds from sale of ordinary shares	50,000
GSK Collaboration Agreement [Member] | Subsequent Event [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment under collaboration agreement	$ 120,000

Significant Accounting Polici_4

Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2022 USD ($) Segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Significant Accounting Policies [Line Items]
Number of operating segment | Segment	1
Cash, cash equivalents and restricted cash	$ 92,157,000	$ 154,215,000	$ 188,148,000
Restricted cash	$ 3,660,000	3,651,000
Revenue, practical expedient, incremental costs of obtaining contract	true
Expected dividend rate	0%
Term deposits purchased and reached maturity	$ 75,000,000
Description of Income tax benefit, likelihood of realized upon ultimate settlement	The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement.
Level 2 | Short-Term Investments [Member]
Significant Accounting Policies [Line Items]
Short-term investments	$ 0	0
Minimum [Member]
Significant Accounting Policies [Line Items]
Income tax examination, likelihood of settlement, percentage	50%
Cambridge MA [Member]
Significant Accounting Policies [Line Items]
Restricted cash	$ 1,000,000	1,000,000
Lexington Facility [Member]
Significant Accounting Policies [Line Items]
Restricted cash	$ 2,700,000	$ 2,700,000

Significant Accounting Polici_5

Significant Accounting Policies - Schedule of Estimated Useful Lives of Assets (Detail)	12 Months Ended
	Dec. 31, 2022
Equipment, Furniture and Software [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives	3 years
Equipment, Furniture and Software [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives	7 years
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives	Shorter of asset life or lease term

Significant Accounting Polici_6

Significant Accounting Policies - Additional Information (Detail 1)	Dec. 31, 2022
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01
Significant Accounting Policies [Line Items]
Revenue recognition performance obligation, expected time satisfaction period	12 months

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Property and equipment gross	$ 55,130	$ 54,496
Less accumulated depreciation	(37,846)	(32,230)
Property and equipment, net	17,284	22,266
Furniture and Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment gross	25,509	25,657
Software [Member]
Property Plant And Equipment [Line Items]
Property and equipment gross	890	817
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment gross	28,413	27,994
Fixed Assets in Progress [Member]
Property Plant And Equipment [Line Items]
Property and equipment gross	$ 318	$ 28

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 6,574	$ 7,483

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued compensation	$ 12,287	$ 10,181
Accrued expenses related to CROs and CMOs	3,516	3,571
Accrued expenses and other current liabilities	1,749	1,109
Total accrued expenses and other current liabilities	$ 17,552	$ 14,861

Collaboration Agreements - Addi

Collaboration Agreements - Additional Information (Detail) $ / shares in Units, $ in Thousands			1 Months Ended		12 Months Ended		59 Months Ended
	Oct. 15, 2021 USD ($)	Apr. 02, 2018	Apr. 30, 2018 USD ($) Target $ / shares shares	Feb. 28, 2018 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2022 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Equity investment aggregate purchase price					$ 51,220
Proceeds from issuance of ordinary shares, net of offering costs					51,220
Revenue					3,649	$ 40,964
Collaboration revenue recognized					3,649	40,964
Collaboration and license agreement, deferred revenue current					31,558	37,098	$ 31,558
Collaboration and license agreement, deferred revenue noncurrent					79,774	77,479	79,774
Takeda [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Fund receivable for research and preclinical activities			$ 60,000
Up-front consideration received			$ 110,000
Collaboration And License Agreement [Member] | Category One Programs [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Percentage of global costs and potential profits sharing ratio			50%
Collaboration And License Agreement [Member] | Takeda [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment under collaboration agreement			$ 110,000
Collaboration and license agreement month and year				2018-02
Fund receivable for research and preclinical activities			$ 60,000
Research term under collaboration and license agreement			4 years
Collaboration agreement commencement date		Apr. 02, 2018
Collaboration agreement termination period		180 days
Collaboration And License Agreement [Member] | Takeda [Member] | Minimum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration agreement, committed cash				$ 230,000
Collaboration And License Agreement [Member] | Takeda [Member] | Category One Programs [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Percentage of global costs and potential profits sharing ratio			50%
Collaboration and License Agreement Date	Oct. 15, 2021
Revenue					3,300	41,000	81,200
Collaboration revenue recognized					3,300	41,000	81,200
Collaboration and license agreement, deferred revenue					111,300	114,600	111,300
Collaboration and license agreement, deferred revenue current					31,600	37,100	31,600
Collaboration and license agreement, deferred revenue noncurrent					$ 79,800	$ 77,500	$ 79,800
Collaboration And License Agreement [Member] | Takeda [Member] | Category Two Programs [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Fund receivable for research and preclinical activities			$ 60,000
Research term under collaboration and license agreement			4 years
Maximum targets for preclinical programs | Target			6
Option to reach maximum targets for preclinical programs					any one time
Collaboration And License Agreement [Member] | Takeda [Member] | Category 1 Programs and Category 2 Programs [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration-budgeted research and preclinical expenses	$ 22,500
Revenue	18,500
Collaboration revenue recognized	$ 18,500
Collaboration and Share Purchase Agreements [Member] | Takeda [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Shares issued under equity agreement | shares			1,096,892
Purchase price per share | $ / shares			$ 54.70
Proceeds from issuance of ordinary shares, net of offering costs			$ 60,000
Equity investment agreement official closure month and year			2018-04

Share Capital - Additional Info

Share Capital - Additional Information (Detail) $ / shares in Units, $ in Thousands		12 Months Ended
	Jun. 16, 2022 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) Vote $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares
Class of Stock [Line Items]
Warrant or Right, Reason for Issuance, Description		On June 16, 2022, the Company closed an underwritten offering (the “June 2022 Offering”) in which the Company issued and sold 25,464,483 of the Company’s ordinary shares at a price of $2.15 per share and pre-funded warrants (the “Pre-Funded Warrants”) to purchase up to 7,093,656 of the Company’s ordinary shares at an offering price of $2.1499 per Pre-Funded Warrant, which represents the per share offering price for the ordinary shares less the $0.0001 per share exercise price for each Pre-Funded Warrant. These Pre-Funded Warrants were recorded as a component of shareholders’ equity within additional paid-in capital. The gross proceeds to the Company from the June 2022 Offering were $70.0 million before deducting underwriting discounts and commissions and other offering expenses. The net proceeds to the Company from the June 2022 Offering were approximately $65.5 million after deducting underwriting commissions and offering expenses. The Pre-Funded Warrants are exercisable at any time after their original issuance and on or prior to the five-year anniversary of the original issuance date. A holder of Pre-Funded Warrants may not exercise the warrant if the holder, together with its affiliates, would beneficially own more than 19.99% of the number of the Company’s ordinary shares outstanding or more than 19.99% of the combined voting power of the Company’s securities outstanding immediately after giving effect to such exercise, unless and until shareholder approval is obtained.
Net proceeds from sale of ordinary shares | $		$ 51,220
Common stock, par value		$ 0	$ 0
Ordinary share holder, voting right		one vote for each ordinary share
Voting rights, votes per share | Vote		1
Preferred stock liquidation preference, per share		$ 10
Singapore [Member]
Class of Stock [Line Items]
Common stock, par value		$ 0
Common stock, authorized | shares		0
Series A Preferred Shares [Member] | Singapore [Member]
Class of Stock [Line Items]
Preferred stock, par value		$ 0
Preferred stock, shares authorized | shares		0
At-The-Market Equity Program [Member]​
Class of Stock [Line Items]
Issuance of ordinary shares, shares | shares		458,092	10,740,915
Net proceeds from sale of ordinary shares after deducting commissions and offering expenses | $		$ 1,200	$ 54,900
June 2022 Offering [Member]
Class of Stock [Line Items]
Issuance of ordinary shares, shares | shares	25,464,483
Purchase price per share	$ 2.15
Gross proceeds from sale of ordinary shares | $	$ 70,000
Net proceeds from sale of ordinary shares | $	$ 65,500
Pre Funded Warrants [Member]
Class of Stock [Line Items]
Purchase price per share	$ 2.1499
Pre-funded warrant exercise price per share	$ 0.0001
Minimum percentage of combined voting power of securities outstanding immediate effect of exercise	19.99%
Pre Funded Warrants [Member] | Maximum [Member]
Class of Stock [Line Items]
Purchase price of pre-funded warrants | shares	7,093,656
Pre Funded Warrants [Member] | Minimum [Member]
Class of Stock [Line Items]
Percentage of ownership interest in ordinary shares outstanding	19.99%

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended
	Oct. 31, 2022	Apr. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Aug. 31, 2022	Aug. 10, 2021
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Options granted			3,844,242
Share-based compensation expense			$ 17,194	$ 16,407
Service Period Of October12022 Through December312024 Member [member] | Scientific Advisor [Member] | Consulting Agreement [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Non-qualified share option granted for service	163,467
Non Employee [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Options granted				0
Time-based RSUs [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Shares granted to employees			143,700
RSUs outstanding			607,764
Unrecognized stock-based compensation weighted average recognition period			1 year 3 months 18 days
Unrecognized stock-based compensation expense			$ 1,700
Performance Based RSUs [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Vesting percentage		50%
Share-based compensation expense not yet recognized			$ 3,800
RSUs outstanding			326,578
RSUs [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Shares granted to employees			143,700
RSUs outstanding			934,342	1,875,350
Fair value of RSUs vested			$ 1,300	$ 1,700
ESPP [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Ordinary shares reserved for issuance			716,413
Share purchase price at equal to fair market value percentage			85%
Issuance of ordinary shares under ESPP, shares			166,061	92,287
Common Stock [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Issuance of ordinary shares, shares			25,464,483
Issuance of ordinary shares under ESPP, shares			166,061	92,287
Common Stock [Member] | Performance Based RSUs [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Issuance of ordinary shares, shares		384,646
Maximum [Member] | Employee Stock Option [Member] | Non Employee [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Share-based compensation expense			$ 100
2021 Plan [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Ordinary shares authorized for issuance					11,450,000	5,450,000
Ordinary shares available for future grant			6,339,480
2014 Plan [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Weighted average grant date fair value per granted option			$ 2.06	$ 3.48
Aggregate fair value of options vested			$ 6,900	$ 5,700
2014 Plan [Member] | Employee Stock Option [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense			$ 9,700
Unrecognized stock-based compensation weighted average recognition period			2 years 3 months 18 days
2014 Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Vesting period			1 year
Contractual life of options			5 years
2014 Plan [Member] | Minimum [Member] | Time-based RSUs [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Vesting period			1 year
2014 Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Vesting period			4 years
Contractual life of options			10 years
2014 Plan [Member] | Maximum [Member] | Time-based RSUs [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Vesting period			4 years

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Share Option Activity (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) $ / shares shares
Share-Based Payment Arrangement, Disclosure [Abstract]
Outstanding, Number of Shares, Beginning Balance | shares	6,958,160
Granted, Number of Shares | shares	3,844,242
Exercised, Number of Shares | shares	(90,000)
Forfeited or cancelled, Number of Shares | shares	(1,030,348)
Outstanding, Number of Shares, Ending Balance | shares	9,682,054
Options exercisable, Number of Shares | shares	4,051,769
Outstanding, Weighted Average Exercise Price, Beginning Balance | $ / shares	$ 10.22
Granted, Weighted Average Exercise Price | $ / shares	3.16
Exercised, Weighted Average Exercise Price | $ / shares	2.48
Forfeited or cancelled, Weighted Average Exercise Price | $ / shares	7.90
Outstanding, Weighted Average Exercise Price, Ending Balance | $ / shares	7.73
Options exercisable, Weighted Average Exercise Price | $ / shares	$ 13.11
Outstanding, Weighted Average Remaining Contractual Term	7 years 21 days
Options exercisable, Weighted Average Remaining Contractual Term	4 years 9 months 7 days
Outstanding, Aggregate Intrinsic Value | $	$ 25,032
Options exercisable, Aggregate Intrinsic Value | $	$ 5,994

Share-Based Compensation - Su_2

Share-Based Compensation - Summary of Fair Value of Share Options Granted to Employees (Detail)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Expected dividend yield	0%
Employee Stock Option [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	1.35%	0.42%
Risk-free interest rate, maximum	4.23%	1.34%
Expected volatility, minimum	63%	71%
Expected volatility, maximum	96%	86%
Expected dividend yield	0%	0%
Employee Stock Option [Member] | Minimum [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Expected term (in years)	3 years	3 years
Employee Stock Option [Member] | Maximum [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days

Share-Based Compensation - Su_3

Share-Based Compensation - Summary of Fair Value of Share Options Granted to Non-employees (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected dividend rate	0%
Employee Stock Option [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected dividend rate	0%	0%
Employee Stock Option [Member] | Non Employee [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate	4.29%
Expected term (in years)	2 years 6 months
Expected volatility	99%
Expected dividend rate	0%

Share-Based Compensation - Su_4

Share-Based Compensation - Summary of RSU Activity (Detail) - RSUs [Member]	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Outstanding, Number of Shares, Beginning Balance | shares	1,875,350
Granted, Number of Shares | shares	143,700
Vested, Number of Shares | shares	(904,891)
Forfeited, Number of Shares | shares	(179,817)
Outstanding, Number of Shares, Ending Balance | shares	934,342
Outstanding, Average Grant Date Fair Value, Beginning Balance | $ / shares	$ 13.70
Granted, Average Grant Date Fair Value | $ / shares	2.94
Vested, Average Grant Date Fair Value | $ / shares	14.20
Forfeited, Average Grant Date Fair Value | $ / shares	17.04
Outstanding, Average Grant Date Fair Value, Ending Balance | $ / shares	$ 10.94

Share-Based Compensation - Su_5

Share-Based Compensation - Summary of Share-based Compensation Expense Classified in Consolidated Statements of Operations and Comprehensive Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 17,194	$ 16,407
Research and Development Expenses [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	7,467	7,267
General and Administrative Expenses [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 9,727	$ 9,140

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Oct. 01, 2021	Sep. 26, 2016	Apr. 30, 2015
Operating Leased Assets [Line Items]
Lease agreement term				5 years
Restricted cash		$ 3,660	$ 3,651
Description of additional lease space		The lease for the additional space commenced on October 1, 2021, with a term of five years and is considered a separate lease from the Cambridge Lease.
Operating lease right-of-use assets		$ 26,843	18,378	$ 4,500
Operating lease liability		$ 37,614		$ 4,500
Lexington, Massachusetts [Member]
Operating Leased Assets [Line Items]
Lease agreement term					10 years 9 months
Renewal options		10 year and 9-month lease, which includes two successive five-year renewal options
Restricted cash		$ 2,700	2,700
Lease renewal term					5 years
Cambridge, Massachusetts [Member]
Operating Leased Assets [Line Items]
Lease agreement term						7 years 6 months
Restricted cash		$ 1,000	$ 1,000
Lease renewal term	5 years					5 years
Lease option to extend description		five-year renewal option to extend the lease
Option to extend the lease		true
Incremental borrowing rate	10.53%
Operating lease right-of-use assets	$ 12,000
Operating lease liability	$ 12,000

Leases - Summary of Lease Costs

Leases - Summary of Lease Costs Recognized and Other Information Pertaining to Operating Leases (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Lease cost
Operating lease cost	$ 6,458	$ 4,742
Variable lease cost	2,508	2,150
Total lease cost	8,966	6,892
Other information
Operating cash flows used for operating leases	7,226	6,275
Increase in operating right-of-use assets	12,006	4,498
Operating lease liabilities arising from obtaining right-of-use assets	$ 12,006	$ 4,498
Weighted average remaining lease term	5 years	5 years 6 months
Weighted average discount rate	9.20%	8.40%

Leases - Schedule of Future Min

Leases - Schedule of Future Minimum Rental Payments for Operating Leases Under Topic 842 (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Oct. 01, 2021
Operating Lease Liabilities, Payments Due [Abstract]
2023	$ 8,655
2024	9,311
2025	9,591
2026	9,584
2027	8,987
Thereafter	886
Total lease payments	47,014
Less: imputed interest	(9,400)
Total operating lease liabilities	$ 37,614	$ 4,500

Net Loss Per Ordinary Share - A

Net Loss Per Ordinary Share - Additional Information (Details) - Pre Funded Warrants [Member]	Dec. 31, 2022 $ / shares shares
Class of Warrant or Right [Line Items]
Pre-funded warrant outstanding | shares	7,093,656
Warrant Exercise Price Per Share | $ / shares	$ 0.0001

Net Loss Per Ordinary Share - S

Net Loss Per Ordinary Share - Summary of Basic and Diluted Net Loss Per Ordinary Share Outstanding (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Numerator:
Net loss attributable to ordinary shareholders	$ (161,823)	$ (122,245)
Denominator:
Weighted-average ordinary shares outstanding, basic	78,855,810	51,825,566
Weighted-average ordinary shares outstanding, diluted	78,855,810	51,825,566
Net loss per share, basic	$ (2.05)	$ (2.36)
Net loss per share, diluted	$ (2.05)	$ (2.36)

Net Loss Per Ordinary Share -_2

Net Loss Per Ordinary Share - Anti-Dilutive Shares Excluded from Calculation of Diluted Net Loss Per Ordinary Share (Detail) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Options to Purchase Ordinary Shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	9,682,054	6,958,160
RSUs [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	934,342	1,875,350
Series A Preferred Shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	3,901,348	3,901,348

Income Taxes - Components of Lo

Income Taxes - Components of Loss before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Taxes [Line Items]
Loss before income taxes	$ (161,142)	$ (122,449)
Singapore [Member]
Income Taxes [Line Items]
Loss before income taxes	(8,714)	(10,842)
Rest Of World [Member]
Income Taxes [Line Items]
Loss before income taxes	$ (152,428)	$ (111,607)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Oct. 31, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2017
Income Taxes [Line Items]
Income tax benefit (provision)		$ (681,000)	$ 204,000
Net operating loss carryovers		158,413,000	170,997,000
Capitalized research and development deferred tax assets		36,643,000
Increase (decrease) in valuation allowance		(11,900,000)
Gross unrecognized tax benefit		13,945,000	19,864,000	$ 18,416,000
Unrecognized tax benefit that could affect annual effective tax rate if recognized		200,000
Subsidiaries Outside of Singapore [Member]
Income Taxes [Line Items]
Cash held by subsidiaries		44,100,000	21,100,000
Japan [Member]
Income Taxes [Line Items]
Net operating loss carryovers		$ 2,300,000	2,700,000
Operating loss carryforwards expiration year		2023
Tax years open to examination		2017
Singapore [Member]
Income Taxes [Line Items]
Net operating loss carryovers		$ 111,200,000	189,200,000
Tax years open to examination		2018
UK [Member]
Income Taxes [Line Items]
Net operating loss carryovers		$ 314,500,000	254,300,000
Tax years open to examination		2021
United States [Member]
Income Taxes [Line Items]
Tax years open to examination		2019
Federal [Member]
Income Taxes [Line Items]
Net operating loss carryforwards		$ 272,400,000
Net operating loss carryforwards available to offset future income tax liabilities indefinitely		$ 271,600,000
Net operating loss carryforwards available to offset future income tax liabilities					$ 800,000
Operating Loss Carry forward expiration year		2037
Federal [Member] | Research and development
Income Taxes [Line Items]
Tax credit carryforward		$ 200,000	12,800,000
Research and development tax credit carryforward expiration year		2042
Federal [Member] | Orphan Drug Credits [Member]
Income Taxes [Line Items]
Tax credit carryforward		$ 0
State [Member]
Income Taxes [Line Items]
Net operating loss carryforwards		$ 43,900,000
Operating Loss Carry forward expiration year		2038
Operating loss carryforwards expiration amount		$ 218,200,000
State [Member] | Research and development
Income Taxes [Line Items]
Tax credit carryforward		$ 200,000	$ 9,100,000
Research and development tax credit carryforward expiration year		2037
Inland Revenue Authority of Singapore (IRAS) [Member] | Singapore [Member]
Income Taxes [Line Items]
Capitalized research and development deferred tax assets	$ 14,900,000
Tax years open to examination	2016 2017
Federal and State [Member]
Income Taxes [Line Items]
Tax credit expiration amount		$ 46,800,000

Income Taxes - Deferred Compone

Income Taxes - Deferred Components of Benefit (Provision), Net for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Current benefit (provision) for income taxes:
Total current benefit (provision) for income taxes	$ (681)	$ 204
Deferred benefit for income taxes:
Total benefit (provision) for income taxes	(681)	204
Rest Of World [Member]
Current benefit (provision) for income taxes:
Total current benefit (provision) for income taxes	$ (681)	$ 204

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Statutory Income Tax Rate (Detail) - Singapore [Member]	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Taxes [Line Items]
Singapore statutory income tax rate	17%	17%
Federal and state tax credits	3.30%	5.10%
Permanent differences	0.10%	(2.60%)
Changes in reserves for uncertain tax positions	0.40%	(2.10%)
Foreign rate differential	8.80%	6.30%
Tax rate change		12.50%
Other	(1.00%)	(1.10%)
Change in deferred tax asset valuation allowance	7.30%	(34.90%)
Deferred tax adjustments	(36.30%)
Effective income tax rate	(0.40%)	0.20%

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss carryforwards	$ 158,413	$ 170,997
Federal and state tax credits	368	40,163
Share-based compensation	7,265	7,194
Accumulated amortization	782	872
Operating lease liabilities	10,276	8,173
Deferred revenue	16,786	13,546
Capitalized research and development	36,643
Other	3,164	2,351
Total deferred tax assets	233,697	243,296
Valuation allowance	(226,273)	(238,170)	$ (195,381)
Net deferred tax assets	7,424	5,126
Deferred tax liabilities:
Operating lease right-of-use assets	(7,333)	(5,021)
Accumulated depreciation	(86)	(98)
Other	(5)	(7)
Total deferred tax liabilities	$ (7,424)	$ (5,126)

Income Taxes - Summary of Valua

Income Taxes - Summary of Valuation Allowance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Deferred Tax Assets, Net of Valuation Allowance [Abstract]
Balance at beginning of year	$ 238,170	$ 195,381
Increase in valuation allowance	3,134	42,886
Decrease in valuation allowance	(14,934)
Effect of foreign currency translation	(97)	(97)
Balance at end of year	$ 226,273	$ 238,170

Income Taxes - Summary of Activ

Income Taxes - Summary of Activity in Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefit at the beginning of the year	$ 19,864	$ 18,416
Tax positions related to prior years	(7,320)	(56)
Tax positions related to statute lapse		(575)
Tax positions related to the current year	1,401	2,079
Unrecognized tax benefit at the end of the year	$ 13,945	$ 19,864

Employee Benefit Plans - Additi

Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
401(k) Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Discretionary contributions to defined contribution pension plan	$ 1.1	$ 1

Related Parties - Additional In

Related Parties - Additional Information (Detail) - Scientific Advisor [Member] - Consulting Agreement [Member] - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2022	Dec. 31, 2022
Related Party Transaction [Line Items]
Consulting agreement termination notice period		14 days
Consulting service expenses		$ 13
Service Period Of October12022 Through December312024 Member [member]
Related Party Transaction [Line Items]
Non-qualified share option granted for service	163,467

Subsequent Events - Additional

Subsequent Events - Additional information (Detail) - USD ($) $ / shares in Units, $ in Thousands			12 Months Ended
	Jan. 01, 2023	Dec. 13, 2022	Dec. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Net proceeds from sale of ordinary shares			$ 51,220
GSK Equity Investment [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Issuance of ordinary shares, shares		10,683,761
Purchase price per share		$ 4.68
Subsequent Event [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Proceeds from collaboration and share purchase agreement	$ 170,000
Subsequent Event [Member] | GSK Equity Investment [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Net proceeds from sale of ordinary shares	50,000
GSK Collaboration Agreement [Member] | Subsequent Event [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment under collaboration agreement	$ 120,000