0001564590-21-010718 | 10-K | XBRL Viewer

Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2020	Feb. 22, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
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 Common Stock, Shares Outstanding		48,997,368
Entity Public Float			$ 267,103,358
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 Tax Identification Number	00-0000000
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
Documents Incorporated by Reference	If the Registrant’s Definitive Proxy Statement relating to the 2021 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 - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 184,497	$ 147,161
Current portion of accounts receivable	30,000	20,000
Prepaid expenses	10,434	9,626
Other current assets	5,111	8,689
Total current assets	230,042	185,476
Long-term assets:
Accounts receivable, net of current portion		30,000
Property and equipment, net	29,198	36,368
Operating lease right-of-use assets	16,232	18,101
Restricted cash	3,651	3,647
Other assets	115	10,658
Total long-term assets	49,196	98,774
Total assets	279,238	284,250
Current liabilities:
Accounts payable	13,795	9,073
Accrued expenses and other current liabilities	11,971	16,185
Current portion of deferred revenue	91,560	89,652
Current portion of operating lease liability	3,714	3,243
Total current liabilities	121,040	118,153
Long-term liabilities:
Deferred revenue, net of current portion	41,481	63,466
Operating lease liability, net of current portion	25,591	29,304
Other liabilities	474	1,721
Total long-term liabilities	67,546	94,491
Total liabilities	188,586	212,644
Series A preferred shares, no par value; 3,901,348 shares issued and outstanding at December 31, 2020 and 2019	7,874	7,874
Shareholders’ equity:
Ordinary shares, no par value; 48,778,678 and 34,340,690 shares issued and outstanding at December 31, 2020 and 2019, respectively	694,085	539,547
Additional paid-in capital	71,573	57,277
Accumulated other comprehensive income	389	267
Accumulated deficit	(683,269)	(533,359)
Total shareholders’ equity	82,778	63,732
Total liabilities, Series A preferred shares and shareholders’ equity	$ 279,238	$ 284,250

Consolidated Statements of Operations and Comprehensive Loss - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenue	$ 20,077,000	$ 15,983,000
Operating expenses:
Research and development	130,944,000	175,431,000
General and administrative	42,510,000	48,869,000
Total operating expenses	173,454,000	224,300,000
Loss from operations	(153,377,000)	(208,317,000)
Other income, net:
Dividend income	584,000	4,912,000
Interest income (expense), net	(16,000)	29,000
Other income, net	2,058,000	9,738,000
Total other income, net	2,626,000	14,679,000
Loss before income taxes	(150,751,000)	(193,638,000)
Income tax benefit (provision), net	841,000	0
Net loss	$ (149,910,000)	$ (193,638,000)
Net loss per share attributable to ordinary shareholders—basic and diluted	$ (3.82)	$ (5.72)
Weighted-average ordinary shares used in computing net loss per share attributable to ordinary shareholders—basic and diluted	39,227,618	33,866,487
Other comprehensive income (loss):
Net loss	$ (149,910,000)	$ (193,638,000)
Foreign currency translation	122,000	114,000
Comprehensive loss	$ (149,788,000)	$ (193,524,000)

Consolidated Statements of Series A Preferred Shares and Shareholders' Equity - USD ($) $ in Thousands	Total	At-The-Market Equity Program [Member]	ESPP [Member]	Series A Preferred Shares [Member]	Ordinary Shares [Member]	Ordinary Shares [Member] At-The-Market Equity Program [Member]	Ordinary Shares [Member] ESPP [Member]	Additional Paid-In-Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2018	$ 73,348				$ 375,148			$ 37,768	$ 153	$ (339,721)
Beginning balance, shares at Dec. 31, 2018					29,472,197
Temporary equity, Beginning balance at Dec. 31, 2018				$ 7,874
Temporary equity, Beginning balance, shares at Dec. 31, 2018				3,901,348
Issuance of ordinary shares	161,792				$ 161,792
Issuance of ordinary shares, shares					4,542,500
Share-based compensation	19,509							19,509
Vesting of RSUs, shares					112,437
Option exercises	2,607				$ 2,607
Option exercises, shares					213,556
Other comprehensive income	114								114
Net loss	(193,638)									(193,638)
Ending balance at Dec. 31, 2019	63,732				$ 539,547			57,277	267	(533,359)
Ending balance, shares at Dec. 31, 2019					34,340,690
Temporary equity, Ending balance at Dec. 31, 2019	$ 7,874			$ 7,874
Temporary equity, Ending balance, shares at Dec. 31, 2019	3,901,348			3,901,348
Issuance of ordinary shares	$ 93,744	$ 59,882	$ 171		$ 93,744	$ 59,882	$ 171
Issuance of ordinary shares, shares		5,583,022			8,333,334	5,583,022	25,239
Share-based compensation	14,296							14,296
Vesting of RSUs, shares					208,123
Option exercises	741				$ 741
Option exercises, shares					288,270
Other comprehensive income	122								122
Net loss	(149,910)									(149,910)
Ending balance at Dec. 31, 2020	82,778				$ 694,085			$ 71,573	$ 389	$ (683,269)
Ending balance, shares at Dec. 31, 2020					48,778,678
Temporary equity, Ending balance at Dec. 31, 2020	$ 7,874			$ 7,874
Temporary equity, Ending balance, shares at Dec. 31, 2020	3,901,348			3,901,348

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net loss	$ (149,910)	$ (193,638)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of right-of-use assets	1,869	1,613
Depreciation of property and equipment	8,114	7,588
Share-based compensation expense	14,296	19,509
Changes in operating assets and liabilities:
Accounts receivable	20,000	10,000
Prepaid expenses	(808)	(3,665)
Other assets	14,121	(8,369)
Accounts payable	5,117	(3,497)
Accrued expenses and other current liabilities	(4,214)	1,448
Deferred revenue	(20,077)	(15,983)
Operating lease liabilities	(3,243)	(2,816)
Other non-current liabilities	(1,247)	(421)
Net cash used in operating activities	(115,982)	(188,231)
Cash flows from investing activities
Purchases of property and equipment	(1,338)	(3,918)
Net cash used in investing activities	(1,338)	(3,918)
Cash flows from financing activities
Proceeds from issuance of ordinary shares, net of offering costs	93,744	161,792
Proceeds from the exercise of share options	741	2,607
Proceeds from the employee share purchase program	171
Net cash provided by financing activities	154,538	164,399
Effect of foreign exchange rates on cash	122	114
Net increase (decrease) in cash, cash equivalents and restricted cash	37,340	(27,636)
Cash, cash equivalents and restricted cash, beginning of period	150,808	178,444
Cash, cash equivalents and restricted cash, end of period	188,148	$ 150,808
At-The-Market Equity Program [Member]
Cash flows from financing activities
Proceeds from issuance of ordinary shares, net of offering costs	$ 59,882

Significant Accounting Policies

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Significant Accounting Policies

2. SIGNIFICANT ACCOUNTING POLICIES

Cash Equivalents

The Company considers all highly liquid securities with original final maturities of three months or less from the date of purchase to be cash equivalents. Cash equivalents are comprised of funds in money market accounts.

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 it concludes substantial doubt exists and it is not alleviated by the Company’s plans or when its 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 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. Cash, cash equivalents and restricted cash were recorded at fair value as of December 31, 2020 and 2019, totaling $188.1 million and $150.8 million, respectively. The carrying amounts of accounts payable and accrued expenses approximate their fair values due to their short-term maturities. Accounts receivable relate to the Company’s collaboration agreements.

Concentration of Credit Risk

Cash and cash equivalents are financial instruments that potentially subject the Company to concentration of credit risk. The Company uses several financial institutions to maintain its cash and cash equivalents, 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, 2020 and 2019, the Company had $3.7 million and $3.6 million of restricted cash, respectively, of which $1.0 million related to the Cambridge facility and the remainder related to the Lexington 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.

For additional discussion of accounting for collaboration revenues, see Note 5.

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. 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.

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 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 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. All equity instruments issued to non-employees as consideration for goods or services received by the Company are accounted for based on the fair value of the equity instruments issued. These awards are recorded in expense and additional paid-in capital in shareholders’ equity over the applicable service periods based on the fair value of the options at the end of each period. The Company accounts for the expense from share-based awards to non-employees by re-measuring the awards at fair value over the vesting period.

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 is limited historical data for the Company’s ordinary shares and limited company-specific historical volatility, it has 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.

•

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

Effective January 1, 2019, the Company adopted ASC 842, Leases (“ASC 842”), using the modified retrospective approach and utilizing the effective date as its date of initial application, for which prior periods are presented in accordance with the previous guidance in ASC 840, Leases (“ASC 840”). In February 2016, the FASB issued ASU No. 2016-02, Leases (“ASU 2016-02”), which was further clarified when the FASB issued ASU No. 2018-10, Codification Improvements to Topic 842, Leases (“ASU 2018-10”), ASU No. 2018-11, Leases (Topic 842)—Targeted Improvements (“ASU 2018-11”), and ASU No. 2019-01, Codification Improvements to Topic 842, Leases (“ASU 2019-01”). The adoption of ASC 842, in accordance with ASU 2016-02, ASU 2018-10, ASU 2018-11, and ASU 2019-01, requires a lessee to recognize assets and liabilities on the balance sheet for operating leases and changes many key definitions, including the definition of a lease. ASC 842 includes a short-term lease exception for leases with a term of 12 months or less, in which a lessee can make an accounting policy election not to recognize lease assets and lease liabilities. Lessees will continue to differentiate between finance leases (previously referred to as capital leases) and operating leases, using classification criteria that are substantially similar to the previous guidance. For lessees, the recognition, measurement, and presentation of expenses and cash flows arising from a lease have not significantly changed from previous U.S. GAAP. Lessees and lessors are required to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. The modified retrospective approach includes a number of optional practical expedients that entities may elect to apply, as well as transition guidance specific to nonstandard leasing transactions. As further described above, the Company adopted ASC 842 on January 1, 2019 using a cumulative-effect adjustment on the effective date of the standard, for which comparative periods are presented in accordance with the previous guidance in ASC 840.

In adopting ASC 842, the Company elected to utilize the available package of practical expedients permitted under the transition guidance within the new standard, which does not require the reassessment of the following: i) whether existing or expired arrangements are or contain a lease, ii) the lease classification of existing or expired leases, and iii) whether previous initial direct costs would qualify for capitalization under the new lease standard. Additionally, the Company made an accounting policy election to not recognize on the balance sheet leases with a term of 12 months or less.

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.

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. In transition to ASC 842, the Company utilized the remaining lease term of its leases in determining the appropriate incremental borrowing rates.

In accordance with ASC 842, components of a lease should be split into three categories: lease components (e.g., land, building, etc.), non-lease components (e.g., common area maintenance, consumables, etc.), and non-components (e.g., property taxes, insurance, etc.). The fixed and in-substance fixed contract consideration (including any consideration related to non-components) must be allocated based on the respective relative fair values to the lease components and non-lease components.

Although separation of lease and non-lease components is required, certain expedients are available. Entities may elect the practical expedient to not separate lease and non-lease components by class of underlying asset. Rather, entities would account for each lease component and the related non-lease component together as a single component. For new and amended leases beginning in 2019 and after, the Company has elected to account for the lease and non-lease components for leases for classes of all underlying assets and allocate all of the contract consideration to the lease component only.

Recently Issued Accounting Pronouncements

In December 2019, the FASB finalized Accounting Standards Update No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”). ASU 2019-12 eliminates certain exceptions in ASC 740 and generally simplifies existing guidance. The new guidance is effective for fiscal years beginning after December 15, 2020, including interim periods within those fiscal years, but may be adopted earlier by entities. The Company is currently evaluating the potential impact that the adoption of ASU 2019-12 may have on its consolidated financial statements.

Collaboration Agreements

12 Months Ended

Dec. 31, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Collaboration Agreements

5. COLLABORATION AGREEMENTS

Pfizer Collaboration and Equity Agreements

In May 2016, the Company entered into a Research, License and Option Agreement (as amended in November 2017, the “Pfizer Collaboration Agreement”) with Pfizer Inc. (“Pfizer”). Pursuant to the terms of the Pfizer Collaboration Agreement, the Company and Pfizer agreed to collaborate on the discovery, development and commercialization of stereopure oligonucleotide therapeutics for up to five programs (the “Pfizer Programs”), each directed at a genetically-defined hepatic target selected by Pfizer (the “Pfizer Collaboration”). The Company received $10.0 million as an upfront license fee under the Pfizer Collaboration Agreement. Subject to option exercises by Pfizer, the Company was entitled to earn potential research, development and commercial milestone payments, plus royalties, tiered up to low double-digits, on sales of any products that may result from the Pfizer Collaboration. None of the payments under the Pfizer Collaboration Agreement are refundable.

Simultaneously with the entry into the Pfizer Collaboration Agreement, the Company entered into a Share Purchase Agreement (the “Pfizer Equity Agreement,” and together with the Pfizer Collaboration Agreement, the “Pfizer Agreements”) with C.P. Pharmaceuticals International C.V., an affiliate of Pfizer (the “Pfizer Affiliate”). Pursuant to the terms of the Pfizer Equity Agreement, the Pfizer Affiliate purchased 1,875,000 of the Company’s ordinary shares (the “Shares”) at a purchase price of $16.00 per share, for an aggregate purchase price of $30.0 million. The Company did not incur any material costs in connection with the issuance of the Shares.

Under the Pfizer Collaboration Agreement, the parties agreed to collaborate during a four-year research term. During the research term, the Company was responsible to use its commercially reasonable efforts to advance up to five programs through to the selection of clinical candidates. At that stage, Pfizer was entitled to elect to license any of these Pfizer Programs exclusively and obtain exclusive rights to undertake the clinical development of the resulting clinical candidates into products and the potential commercialization of any such products thereafter. In addition, the Company received a non-exclusive, royalty-bearing sublicensable license to use Pfizer’s hepatic targeting technology in any of the Company’s own hepatic programs that are outside the scope of the Pfizer Collaboration (the “Wave Programs”). If the Company uses this technology on the Wave Programs, Pfizer is eligible to receive potential development and commercial milestone payments from the Company. Pfizer is also eligible to receive tiered royalties on sales of any products that include Pfizer’s hepatic targeting technology. The Company is not currently utilizing Pfizer’s hepatic targeting technology in any of its own hepatic programs that are outside of the scope of the Pfizer Collaboration Agreement.

The stated term of the Pfizer Collaboration Agreement commenced on May 5, 2016 and terminates on the date of the last to expire payment obligation with respect to each Pfizer Program and, with respect to each Wave Program, expires on a program-by-program basis accordingly. Pfizer may terminate its rights related to a Pfizer Program under the Pfizer Collaboration Agreement at its own convenience upon 90 days’ notice to the Company. The Company may also terminate its rights related to a Wave Program at its own convenience upon 90 days’ notice to Pfizer. The Pfizer Collaboration Agreement may also be terminated by either party in the event of an uncured material breach of the Pfizer Collaboration Agreement by the other party.

Pfizer nominated two hepatic targets upon entry into the Pfizer Collaboration in May 2016. The Pfizer Collaboration Agreement provided Pfizer with options to nominate up to three additional programs by making nomination milestone payments. Pfizer nominated the third, fourth and fifth hepatic targets in August 2016, March 2018 and April 2018, respectively.

The Pfizer Collaboration is managed by a joint steering committee in which both parties are represented equally, which will oversee the scientific progression of each Pfizer Program up to the clinical candidate stage. During the four-year research term and for a period of two years thereafter, the Company has agreed to work exclusively with Pfizer with respect to using any of the Company’s stereopure oligonucleotide technology that is specific for the applicable hepatic target which is the basis of any Pfizer Program. Within a specified period after receiving a data package for a candidate under each nominated program, Pfizer may exercise an option to obtain a license to develop, manufacture and commercialize the program candidate by paying an exercise price per program.

The Company assessed this arrangement in accordance with ASC 606 and concluded that the contract counterparty, Pfizer, is a customer. The Company identified the following promises under the arrangement: (1) the non-exclusive, royalty-free research and development license; (2) the research and development services for Programs 1 and 2; (3) the program nomination options for Programs 3, 4 and 5; (4) the research and development services associated with Programs 3, 4 and 5; (5) the options to obtain a license to develop, manufacture and commercialize Programs 1 and 2; and (6) the options to obtain a license to develop, manufacture and commercialize Programs 3, 4 and 5. The research and development services for each of Programs 1 and 2 were determined to not be distinct from the research and development license and should be combined into a single performance obligation for each program. The promises under the Pfizer Collaboration Agreement relate primarily to the research and development required by the Company for each of the programs nominated by Pfizer.

Additionally, the Company determined that the program nomination options for Programs 3, 4 and 5 were priced at a discount and, as such, provide material rights to Pfizer, representing three separate performance obligations. The research and development services associated with Programs 3, 4 and 5 and the options to obtain a license to develop, manufacture and commercialize Programs 3, 4 and 5 are subject to Pfizer’s exercise of the program nomination options for such programs and therefore do not represent performance obligations at the outset of the arrangement. The options to obtain a license to develop, manufacture and commercialize Programs 1

and 2 do not represent material rights; as such, they are not representative of performance obligations at the outset of the arrangement. Based on these assessments, the Company identified five performance obligations in the Pfizer Collaboration Agreement: (1) research and development services and license for Program 1; (2) research and development services and license for Program 2; (3) material right provided for the option to nominate Program 3; (4) material right provided for the option to nominate Program 4; and (5) material right provided for the option to nominate Program 5.

At the outset of the arrangement, the transaction price included only the $10.0 million up-front consideration received. The Company determined that the Pfizer Collaboration Agreement did not contain a significant financing component. The program nomination option exercise fees for research and development services associated with Programs 3, 4 and 5 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 Pfizer Collaboration Agreement. The exercise fees for the options to obtain a license to develop, manufacture and commercialize Programs 3, 4 and 5 that may be received are excluded from the transaction price until each customer option is exercised. 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, and, if necessary, will adjust its estimate of the transaction price.

During the year ended December 31, 2017, it became probable that a significant reversal of cumulative revenue would not occur for a developmental milestone under the Pfizer Collaboration Agreement. At such time, the associated consideration was added to the estimated transaction price and allocated to the existing performance obligations, and the Company recognized a cumulative catch-up to revenue for this developmental milestone, representing the amount that would have been recognized had the milestone payment been included in the transaction price from the outset of the arrangement. The remainder will be recognized in the same manner as the remaining, unrecognized transaction price over the remaining period until each performance obligation is satisfied.

Revenue associated with the performance obligations relating to Programs 1 and 2 is being recognized as revenue as the research and development services are provided using an input method, according to the full-time employee (“FTE”) hours incurred on each program and the FTE hours expected to be incurred in the future to satisfy the performance obligation. The transfer of control occurs over time and, in management’s judgment, this input method is the best measure of progress towards satisfying the performance obligation. The amount allocated to the three material rights will be recognized as the underlying research and development services are provided commencing from the date that Pfizer 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.

Pfizer nominated the third, fourth and fifth hepatic targets in August 2016, March 2018 and April 2018, respectively. Upon each exercise, the Company allocated the transaction price amount allocated to the material right at inception of the arrangement plus the program nomination option exercise fee paid by Pfizer at the time of exercising the option to a new performance obligation, which will be recognized as revenue as the research and development services are provided using the same method as the performance obligations relating to Programs 1 and 2.

The research term for the Pfizer Collaboration Agreement ended by its original terms in May 2020. Through December 31, 2020, the Company had recognized revenue of $18.5 million as collaboration revenue in the Company’s consolidated statements of operations and comprehensive loss under the Pfizer Collaboration Agreement. During the years ended December 31, 2020 and 2019, the Company recognized revenue of $1.5 million and $7.1 million, respectively, under the Pfizer Collaboration Agreement.

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 Wave with at least $230.0 million in committed cash and Takeda with the option to co-develop and co-commercialize Wave’s CNS development programs in (1) Huntington’s disease (“HD”); (2) amyotrophic lateral sclerosis (“ALS”) and frontotemporal dementia (“FTD”); and (3) Wave’s discovery-stage program targeting ATXN3 for the treatment of spinocerebellar ataxia 3 (“SCA3”) (collectively, “Category 1 Programs”). In addition, Takeda will have 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 Wave $110.0 million as an upfront payment. Takeda also agreed to fund Wave’s research and preclinical activities in the amount of $60.0 million during the four-year research term and to reimburse Wave 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, Wave 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, Wave 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 Wave will be eligible to receive development and commercial milestone payments. In addition to its 50% profit share, Wave 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, Wave has 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 parties may collaborate on preclinical programs for up to six targets at any one time. Wave will be 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 will have an exclusive worldwide license to develop and commercialize products and companion diagnostics directed to such targets, subject to Wave’s retained rights to lead manufacturing activities for products directed to such targets. Takeda will fund Wave’s research and preclinical activities in the amount of $60.0 million during the research term and will reimburse Wave for any collaboration-budgeted research and preclinical expenses incurred by Wave that exceed that amount. Wave is 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 grants 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, Wave 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, Wave 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 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 be 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. Revenue associated with the research and preclinical development services for the Category 2 Programs performance obligation is being recognized as the research and preclinical development services are 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 transfer of control for these performance obligations occurs over time and, in management’s judgment, this input method is the best measure of progress towards satisfying the performance obligations. 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.

Through December 31, 2020, the Company had recognized revenue of $37.0 million under the Takeda Collaboration Agreement as collaboration revenue in the Company’s consolidated statements of operations and comprehensive loss. During the years ended December 31, 2020 and 2019, the Company recognized revenue of $18.6 million and $8.8 million, respectively, under the Takeda Collaboration Agreement 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 at December 31, 2020 is $133.0 million, of which $91.6 million is included in current liabilities. 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 and the Category 2 Programs 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. The aggregate amount of the transaction price included in accounts receivable at December 31, 2020 is $30.0 million, all of which is included in current assets.

Share-Based Compensation

12 Months Ended

Dec. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Share-Based Compensation

7. SHARE-BASED COMPENSATION

In December 2014, the Company’s board of directors adopted the Wave Life Sciences Ltd. 2014 Equity Incentive Plan (the “2014 Plan”). The 2014 Plan authorizes the board of directors or a committee of the board to grant incentive share options, non-qualified share options, share appreciation rights, restricted awards, which include restricted shares and restricted share units (“RSUs”), and performance awards to eligible employees, consultants and directors of the Company. The Company accounts for grants to its board of directors as grants to employees.

As of December 31, 2020, 2,324,228 ordinary shares remained available for future grant under the 2014 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 2014 Plan, material to an individual's entering into employment with the Company.

Share option activity under the 2014 Plan is summarized as follows:

	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)⁽¹⁾
Outstanding as of January 1, 2020		3,838,549		$	19.54
Granted		1,024,010			8.55
Exercised		(288,270	)		2.57
Forfeited or cancelled		(700,894	)		31.91
Outstanding as of December 31, 2020		3,873,395		$	15.67		5.63	$	5,794
Options exercisable as of December 31, 2020		2,783,041		$	16.37		4.58	$	5,792

(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. Of the options granted in 2020, 103,000 options were granted outside of the 2014 Plan, as inducement grants material to certain individuals entering into employment with the Company.

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,
	2020	2019
Risk-free interest rate	0.19% – 0.84%	1.34% – 2.62%
Expected term (in years)	3.0 – 6.1	3.0 – 6.1
Expected volatility	69% – 74%	68% – 74%
Expected dividend yield	0%	0%

There were no options granted to non-employees during the years ended December 31, 2020 and 2019.

RSU activity for the year ended December 31, 2020 is summarized as follows:

	RSUs			Average Grant Date Fair Value (in dollars per share)
Outstanding as of January 1, 2020		1,751,862		$	41.81
Granted		77,125			9.17
Vested		(208,123	)		39.98
Forfeited		(440,649	)		37.59
RSUs Outstanding at December 31, 2020		1,180,215		$	41.57

RSUs that are forfeited are available to be granted again. Of the RSUs outstanding at December 31, 2020, 452,194 are time-based RSUs and 728,021 are performance-based RSUs. Time-based RSUs generally vest over periods of one to four years. Vesting of the performance-based RSUs is contingent on the occurrence of certain regulatory or commercial milestones. The Company did not recognize expense in 2020 or 2019 related to the performance-based RSUs as the related milestones were not considered probable of achievement. Of the RSUs granted in 2020, 27,000 were granted outside of the 2014 Plan, as inducement grants material to certain individuals entering into employment with the Company.

As of December 31, 2020, the unrecognized compensation cost related to outstanding options was $7.2 million. The unrecognized compensation cost related to outstanding options is expected to be recognized over a weighted-average period of approximately 1.5 years. For the years ended December 31, 2020 and 2019, the weighted-average grant date fair value per granted option was $5.07 and $11.95, respectively. The aggregate fair value of options that vested during the years ended December 31, 2020 and 2019 was $9.6 million and $15.2 million, respectively. The unrecognized compensation costs related to outstanding time-based RSUs was $10.7 million as of December 31, 2020, and is expected to be recognized over a weighted-average period of approximately 2.0 years. The total fair value of RSUs vested during the years ended December 31, 2020 and 2019 was $1.6 million and $4.2 million, respectively.

Employee Share Purchase Plan

The Wave Life Sciences Ltd. Employee Share Purchase Plan (“ESPP”) allows all 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. Eligible employees who elected to participate in the ESPP were able to participate in the ESPP for the first time beginning on January 15, 2020. During the year ended December 31, 2020, 25,239 ordinary shares were issued under the ESPP. As of December 31, 2020, there were 974,761 ordinary shares available for issuance under the ESPP.

Share-based compensation expense for the years ended December 31, 2020 and 2019 is classified as operating expenses in the consolidated statements of operations and comprehensive loss as follows:

	For the Year Ended December 31,
	2020		2019
	(in thousands)
Research and development expenses	$	6,779	$	9,479
General and administrative expenses		7,517		10,030
Total share-based compensation expense	$	14,296	$	19,509

Leases

12 Months Ended

Dec. 31, 2020

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

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. 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 and $2.6 million in a separate bank account as of December 31, 2020 and 2019, respectively.

As of December 31, 2018, the Company had received $11.4 million of tenant improvement allowances, which was the maximum amount allowed per the lease for the Lexington, Massachusetts facility. In applying the ASC 842 transition guidance, the Company utilized the operating lease classification and recorded a lease liability and a right-of-use asset on the ASC 842 effective date, with the lease incentive obligation being de-recognized and serving to reduce the right-of-use asset.

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. 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, 2020 and 2019. In applying the ASC 842 transition guidance, the Company utilized the operating lease classification and recorded lease liability and a right-of-use asset on the ASC 842 effective date.

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 will constitute the entire building. The lease for the additional space is expected to commence on October 1, 2021 with a term of five years. Future minimum lease payments related to this non-cancelable operating lease for the additional space total $5.4 million, of which $0.3 million is related to payments in 2021 and $5.1 million is related to payments beyond 2021. As the lease term for the additional space has not yet commenced, the Company has not yet recognized rent expense for the additional space and the future minimum lease payments are not included in the table below. On the commencement date of the lease of the additional space in 2021, the Company will record a right-of-use asset and corresponding operating lease liability on its consolidated balance sheets and begin recognizing straight-line rent expense under ASC 842. The Company has not made any payments to date related to this lease of the additional space.

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 year ended December 31, 2020:

	For the Year Ended December 31,
	2020			2019
	(in thousands)
Lease cost
Operating lease cost	$	4,472		$	4,472
Total lease cost	$	4,472		$	4,472

Other information
Operating cash flows used for operating leases	$	5,846		$	5,675
Operating lease liabilities arising from obtaining right-of-use assets	$	—		$	—
Weighted average remaining lease term	6.4 years			7.3 years
Weighted average discount rate		8.5	%		8.5	%

Future minimum lease payments under the Company’s non-cancelable operating leases as of December 31, 2020, are as follows:

	As of December 31, 2020
	(in thousands)
2021		6,021
2022		6,201
2023		5,236
2024		5,002
2025		5,152
Thereafter		10,773
Total lease payments	$	38,385
Less: imputed interest		(9,080	)
Total operating lease liabilities	$	29,305

Income Taxes

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Income Taxes

11. INCOME TAXES

The components of loss before income taxes were as follows:

	Year Ended December 31,
	2020			2019
	(in thousands)
Singapore	$	(9,931	)	$	(5,931	)
Rest of world		(140,820	)		(187,707	)
Loss before income taxes	$	(150,751	)	$	(193,638	)

During the year ended December 31, 2020, the Company recorded an income tax benefit of $0.8 million, which 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. During the year ended December 31, 2019, the Company recorded no income tax benefit or provision.

During the year ended December 31, 2020, the Company recorded no income tax benefit for the net operating losses incurred in Singapore and the United Kingdom, due to uncertainty regarding future taxable income in those jurisdictions. During the year ended December 31, 2019, the Company recorded no income tax benefit for the net operating losses incurred in Singapore, the United States, and the United Kingdom, due to uncertainty regarding future taxable income in those jurisdictions. In May 2016, the Company established a wholly-owned subsidiary in Ireland, however no income tax expense or benefit has been recorded during the years ended December 31, 2020 or 2019.

The components of the benefit (provision), net for income taxes were as follows:

	Year Ended December 31,
	2020		2019
	(in thousands)
Current benefit (provision), net for income taxes:
Singapore	$	—	$	—
Rest of world		841		—
Total current benefit (provision), net for income taxes	$	841	$	—
Deferred benefit (provision), net for income taxes:
Singapore	$	—	$	—
Rest of world		—		—
Total deferred benefit (provision), net for income taxes	$	—	$	—
Total benefit (provision), net for income taxes	$	841	$	—

A reconciliation of the Singapore statutory income tax rate to the Company’s effective income tax rate is as follows:

	Year Ended December 31,
	2020			2019
Singapore statutory income tax rate		17.0	%		17.0	%
Federal and state tax credits		5.4			9.4
Permanent differences		(2.4	)		(1.5	)
Changes in reserves for uncertain tax positions		(1.3	)		(3.2	)
Foreign rate differential		6.1			7.0
Tax rate change		2.6			(0.4	)
Other		(1.2	)		1.3
Change in deferred tax asset valuation allowance		(25.6	)		(29.6	)
Effective income tax rate		0.6	%		—

The components of the Company’s deferred tax assets and liabilities as of December 31, 2020 and 2019 are as follows:

	December 31,
	2020			2019
	(in thousands)
Deferred tax assets:
Net operating loss carryforwards	$	133,841		$	89,585
Federal and state tax credits		36,151			31,336
Share-based compensation		5,880			6,342
Accumulated amortization		962			11,169
Operating lease liabilities		8,006			8,892
Deferred revenue		13,956			14,299
Other		1,146			424
Total deferred tax assets		199,942			162,047
Valuation allowance		(195,381	)		(156,680	)
Net deferred tax assets		4,561			5,367
Deferred tax liabilities:
Operating lease right-of-use assets		(4,435	)		(4,945	)
Accumulated depreciation		(117	)		(422	)
Other		(9	)		—
Total deferred tax liabilities		(4,561	)		(5,367	)
Net deferred tax assets (liabilities)	$	—		$	—

A roll-forward of the valuation allowance for the years ended December 31, 2020 and 2019 is as follows:

	Year Ended December 31,
	2020		2019
	(in thousands)
Balance at beginning of year	$	156,680	$	99,438
Increase in valuation allowance		38,653		57,235
Effect of foreign currency translation		48		7
Balance at end of year	$	195,381	$	156,680

As of December 31, 2020, the Company had federal net operating loss carryforwards in the United States of $213.5 million, $211.5 million of which may be available to offset future income tax liabilities indefinitely, while $2.0 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, 2020, the Company had state net operating loss carryforwards of $206.0 million that will begin to expire in 2038. As of December 31, 2020 and 2019, the Company had U.S. federal research and development tax credit carryforwards of approximately $10.3 million and $8.9 million, respectively, available to offset future U.S. federal income taxes and will begin to expire in 2031. As of December 31, 2020 and 2019, the Company had state research and development tax credit carryforwards of approximately $7.4 million and $6.3 million, respectively, available to offset future state income taxes and will begin to expire in 2033, and state investment tax credit carryforwards of $0.7 million and $1.1 million, respectively, that will begin to expire in 2021. As of December 31, 2020, the Company had a U.S. orphan drug credit carryforward of $19.4 million that will begin to expire in 2037.

As of December 31, 2020 and 2019, the Company had net operating loss carryforwards in Japan of $3.0 million and $2.9 million, respectively, which may be available to offset future income tax liabilities and begin to expire in 2023.

As of December 31, 2020 and 2019, the Company had net operating loss carryforwards in Singapore of $179.3 million and $171.6 million, respectively, which may be available to offset future income tax liabilities and can be carried forward indefinitely.

As of December 31, 2020 and 2019, the Company had net operating loss carryforwards in the United Kingdom of $233.3 million and $133.1 million, 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, 2020, 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, 2020.

The valuation allowance increased by approximately $38.7 million in 2020 and $57.2 million in 2019 primarily as a result of operating losses generated with no corresponding financial statement benefit. 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:

	2020			2019
	(in thousands)
Unrecognized tax benefit at the beginning of the year	$	16,682		$	10,219
Tax positions related to prior years		(310	)		(14	)
Tax positions related to statute lapse		(313	)		(23	)
Tax positions related to the current year		2,357			6,500
Unrecognized tax benefit at the end of the year	$	18,416		$	16,682

As of December 31, 2020 and 2019, the total amount of gross unrecognized tax benefits, which excludes interest and penalties, was $18.4 million and $16.7 million, respectively. At December 31, 2020, $0.2 million of the net unrecognized tax benefits would affect the Company’s annual effective tax rate if recognized.

The Company anticipates that $0.2 million of the total unrecognized tax benefits at December 31, 2020 will decrease within the next twelve months due to a statute lapse.

The Company’s policy is to record interest and penalties related to uncertain tax positions as part of its income tax provision. As of December 31, 2020 and 2019, the Company had recorded less than $0.1 million of interest or penalties related to uncertain tax positions.

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 2016 to the present are still open to examination in the United States, from 2016 to the present in Japan, from 2016 to the present in Singapore and from 2018 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.

As of December 31, 2020 and 2019, $61.0 million and $17.2 million, respectively, of cash was 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 Internal Revenue Code of 1986, as amended (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, the Company completed a study to assess whether an ownership change has occurred or whether there have been multiple ownership changes since its formation. The results of this study indicated that the Company experienced ownership changes as defined by Section 382 of the Code. Based on the results of the study, management has 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. Should an ownership change have occurred after December 31, 2018 or occur in the future, the Company’s ability to utilize its net operating losses and research and development tax credit carryforwards may be limited.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Cash Equivalents

Principles of Consolidation

Use of Estimates

Segment Data

Going Concern

Foreign Currency Translation

Fair Value of Financial Instruments

Level 1—Unadjusted quoted prices in active markets that are accessible at the measurement date of identical, unrestricted assets.

Concentration of Credit Risk

Restricted Cash

Property and Equipment

Equipment, Furniture and Software	3-7 years
Leasehold Improvements	Shorter of asset life or lease term

Impairment of Long-Lived Assets

Revenue Recognition

The Company recognizes revenue in accordance with Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers (“ASC 606”).

For additional discussion of accounting for collaboration revenues, see Note 5.

Research and Development Expenses

License Agreements and Patent Costs

Refundable Tax Credits

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

Share-Based Compensation

•

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 recognizes interest and penalties related to uncertain tax positions in the income tax provision on the consolidated statements of operations and comprehensive loss.

Leases

Recently Issued Accounting Pronouncements

Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Compensation Arrangement By Share-based Payment Award [Line Items]

Summary of Share Option Activity

Share option activity under the 2014 Plan is summarized as follows:

	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)⁽¹⁾
Outstanding as of January 1, 2020		3,838,549		$	19.54
Granted		1,024,010			8.55
Exercised		(288,270	)		2.57
Forfeited or cancelled		(700,894	)		31.91
Outstanding as of December 31, 2020		3,873,395		$	15.67		5.63	$	5,794
Options exercisable as of December 31, 2020		2,783,041		$	16.37		4.58	$	5,792

(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, 2020 is summarized as follows:

	RSUs			Average Grant Date Fair Value (in dollars per share)
Outstanding as of January 1, 2020		1,751,862		$	41.81
Granted		77,125			9.17
Vested		(208,123	)		39.98
Forfeited		(440,649	)		37.59
RSUs Outstanding at December 31, 2020		1,180,215		$	41.57

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, 2020 and 2019 is classified as operating expenses in the consolidated statements of operations and comprehensive loss as follows:

	For the Year Ended December 31,
	2020		2019
	(in thousands)
Research and development expenses	$	6,779	$	9,479
General and administrative expenses		7,517		10,030
Total share-based compensation expense	$	14,296	$	19,509

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,
	2020	2019
Risk-free interest rate	0.19% – 0.84%	1.34% – 2.62%
Expected term (in years)	3.0 – 6.1	3.0 – 6.1
Expected volatility	69% – 74%	68% – 74%
Expected dividend yield	0%	0%

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Components of Loss before Income Taxes

The components of loss before income taxes were as follows:

	Year Ended December 31,
	2020			2019
	(in thousands)
Singapore	$	(9,931	)	$	(5,931	)
Rest of world		(140,820	)		(187,707	)
Loss before income taxes	$	(150,751	)	$	(193,638	)

Deferred Components of Benefit (Provision), Net for Income Taxes

The components of the benefit (provision), net for income taxes were as follows:

	Year Ended December 31,
	2020		2019
	(in thousands)
Current benefit (provision), net for income taxes:
Singapore	$	—	$	—
Rest of world		841		—
Total current benefit (provision), net for income taxes	$	841	$	—
Deferred benefit (provision), net for income taxes:
Singapore	$	—	$	—
Rest of world		—		—
Total deferred benefit (provision), net for income taxes	$	—	$	—
Total benefit (provision), net for income taxes	$	841	$	—

Components of Deferred Tax Assets and Liabilities

The components of the Company’s deferred tax assets and liabilities as of December 31, 2020 and 2019 are as follows:

	December 31,
	2020			2019
	(in thousands)
Deferred tax assets:
Net operating loss carryforwards	$	133,841		$	89,585
Federal and state tax credits		36,151			31,336
Share-based compensation		5,880			6,342
Accumulated amortization		962			11,169
Operating lease liabilities		8,006			8,892
Deferred revenue		13,956			14,299
Other		1,146			424
Total deferred tax assets		199,942			162,047
Valuation allowance		(195,381	)		(156,680	)
Net deferred tax assets		4,561			5,367
Deferred tax liabilities:
Operating lease right-of-use assets		(4,435	)		(4,945	)
Accumulated depreciation		(117	)		(422	)
Other		(9	)		—
Total deferred tax liabilities		(4,561	)		(5,367	)
Net deferred tax assets (liabilities)	$	—		$	—

Summary of Valuation Allowance

A roll-forward of the valuation allowance for the years ended December 31, 2020 and 2019 is as follows:

	Year Ended December 31,
	2020		2019
	(in thousands)
Balance at beginning of year	$	156,680	$	99,438
Increase in valuation allowance		38,653		57,235
Effect of foreign currency translation		48		7
Balance at end of year	$	195,381	$	156,680

Summary of Activity in Unrecognized Tax Benefits

A summary of activity in the Company’s unrecognized tax benefits is as follows:

	2020			2019
	(in thousands)
Unrecognized tax benefit at the beginning of the year	$	16,682		$	10,219
Tax positions related to prior years		(310	)		(14	)
Tax positions related to statute lapse		(313	)		(23	)
Tax positions related to the current year		2,357			6,500
Unrecognized tax benefit at the end of the year	$	18,416		$	16,682

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,
	2020			2019
Singapore statutory income tax rate		17.0	%		17.0	%
Federal and state tax credits		5.4			9.4
Permanent differences		(2.4	)		(1.5	)
Changes in reserves for uncertain tax positions		(1.3	)		(3.2	)
Foreign rate differential		6.1			7.0
Tax rate change		2.6			(0.4	)
Other		(1.2	)		1.3
Change in deferred tax asset valuation allowance		(25.6	)		(29.6	)
Effective income tax rate		0.6	%		—

Collaboration Agreements - Additional Information (Detail)			1 Months Ended			12 Months Ended		35 Months Ended	56 Months Ended
	Apr. 02, 2018	May 05, 2016 USD ($)	Apr. 30, 2018 USD ($) Target $ / shares shares	Feb. 28, 2018 USD ($)	May 31, 2016 USD ($) Program $ / shares shares	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Equity investment aggregate purchase price						$ 93,744,000	$ 161,792,000
Proceeds from issuance of ordinary shares, net of offering costs						93,744,000	161,792,000
Collaboration revenue recognized						20,077,000	15,983,000
Collaboration and license agreement, deferred revenue current						$ 91,560,000	89,652,000	$ 91,560,000	$ 91,560,000
Pfizer Inc. [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of research programs, counterparty nomination \| Program					5
Research term, description						Under the Pfizer Collaboration Agreement, the parties agreed to collaborate during a four-year research term. During the research term, the Company was responsible to use its commercially reasonable efforts to advance up to five programs through to the selection of clinical candidates. At that stage, Pfizer was entitled to elect to license any of these Pfizer Programs exclusively and obtain exclusive rights to undertake the clinical development of the resulting clinical candidates into products and the potential commercialization of any such products thereafter.
Collaboration agreement, additional period after research program		2 years
Up-front consideration received		$ 10,000,000.0
Revenue recognized						$ 1,500,000	7,100,000		18,500,000
Takeda [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Up-front consideration received			$ 110,000,000.0
Research, License and Option Agreement [Member] \| Pfizer Inc. [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment under collaboration agreement					$ 10,000,000.0
Collaboration agreement refundable					$ 0
Shares issued under equity agreement \| shares					1,875,000
Equity investment aggregate purchase price					$ 30,000,000.0
Purchase price per share \| $ / shares					$ 16.00
Collaborative agreement research term					4 years
Collaboration agreement termination period		90 days
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			50.00%
Collaboration And License Agreement [Member] \| Takeda [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment under collaboration agreement			$ 110,000,000.0
Collaboration agreement termination period	180 days
Collaboration and license agreement month and year			2018-02
Fund receivable for research and preclinical activities			$ 60,000,000.0
Research term under collaboration and license agreement			4 years
Collaboration agreement commencement date	Apr. 02, 2018
Collaboration revenue recognized						18,600,000	$ 8,800,000	37,000,000.0
Collaboration and license agreement, deferred revenue						133,000,000.0		133,000,000.0	133,000,000.0
Collaboration and license agreement, deferred revenue current						91,600,000		91,600,000	91,600,000
Collaboration and license agreement, accounts receivable						$ 30,000,000.0		$ 30,000,000.0	$ 30,000,000.0
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			50.00%
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			$ 60,000,000.0
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] \| Minimum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration agreement, committed cash				$ 230,000,000.0
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			$ 60,000,000.0
Equity investment agreement official closure month and year			2018-04

Share-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Non Employee [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Options granted	0	0
Options Granted Outside of 2014 Plan As Inducement Grants [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Options granted	103,000
Time-based RSUs [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Shares granted to employees	452,194
Unrecognized stock-based compensation weighted average recognition period	2 years
Unrecognized stock-based compensation expense	$ 10.7
Performance Based RSUs [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Shares granted to employees	728,021
RSUs Granted Outside of 2014 Plan As Inducement Grants [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Shares granted to employees	27,000
RSUs [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Shares granted to employees	77,125
Fair value of RSUs vested	$ 1.6	$ 4.2
ESPP [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Ordinary shares reserved for issuance	974,761
Share purchase price at equal to fair market value percentage	85.00%
Number of shares issued	25,239
2014 Plan [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Ordinary shares available for future grant	2,324,228
Options granted	1,024,010
Weighted average grant date fair value per granted option	$ 5.07	$ 11.95
Aggregate fair value of options vested	$ 9.6	$ 15.2
2014 Plan [Member] \| Employee Stock Option [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense	$ 7.2
Unrecognized stock-based compensation weighted average recognition period	1 year 6 months
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

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Income tax benefit (provision)	$ 841,000	$ 0
Net operating loss carryovers	133,841,000	89,585,000
Increase in valuation allowance	38,700,000	57,200,000
Gross unrecognized tax benefit	18,416,000	16,682,000	$ 10,219,000
Unrecognized tax benefit that could affect annual effective tax rate if recognized	200,000
Unrecognized tax benefits decrease within next twelve months due to statute lapse	200,000
Subsidiaries Outside of Singapore [Member]
Income Taxes [Line Items]
Cash held by subsidiaries	61,000,000.0	17,200,000
Maximum [Member]
Income Taxes [Line Items]
Interest and penalties related to uncertain tax positions	100,000	100,000
Federal [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	213,500,000
Net operating loss carryforwards available to offset future income tax liabilities indefinitely	$ 211,500,000
Net operating loss carryforwards available to offset future income tax liabilities				$ 2,000,000.0
Operating Loss Carry forward expiration year	2037
Federal [Member] \| Research and development
Income Taxes [Line Items]
Tax credit carryforward	$ 10,300,000	8,900,000
Research and development tax credit carryforward expiration year	2031
Federal [Member] \| Orphan Drug Credits [Member]
Income Taxes [Line Items]
Tax credit carryforward	$ 19,400,000
U.S.Orphan drug credit carryforward expiration year	2037
State [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	$ 206,000,000.0
Operating Loss Carry forward expiration year	2038
State [Member] \| Research and development
Income Taxes [Line Items]
Tax credit carryforward	$ 7,400,000	6,300,000
Research and development tax credit carryforward expiration year	2033
State [Member] \| Investment
Income Taxes [Line Items]
Tax credit carryforward	$ 700,000	1,100,000
Investment tax credit carryforward expiration year	2021
Singapore [Member]
Income Taxes [Line Items]
Income tax benefit (provision)	$ 0	0
Net operating loss carryovers	$ 179,300,000	171,600,000
Tax years open to examination	2016
UK [Member]
Income Taxes [Line Items]
Income tax benefit (provision)	$ 0	0
Net operating loss carryovers	$ 233,300,000	133,100,000
Tax years open to examination	2018
US [Member]
Income Taxes [Line Items]
Income tax benefit (provision)		0
Tax years open to examination	2016
Ireland [Member]
Income Taxes [Line Items]
Income tax benefit (provision)	$ 0	0
Japan [Member]
Income Taxes [Line Items]
Net operating loss carryovers	$ 3,000,000.0	$ 2,900,000
Operating loss carryforwards expiration year	2023
Tax years open to examination	2016

Significant Accounting Policies - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) Segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Significant Accounting Policies [Line Items]
Number of operating segment \| Segment	1
Cash, cash equivalents and restricted cash	$ 188,148	$ 150,808	$ 178,444
Restricted cash	$ 3,651	3,647
Revenue, practical expedient, incremental costs of obtaining contract	true
Expected dividend rate	0.00%
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.
Minimum [Member]
Significant Accounting Policies [Line Items]
Income tax examination, likelihood of settlement, percentage	50.00%
Cambridge MA [Member]
Significant Accounting Policies [Line Items]
Restricted cash	$ 1,000	$ 1,000

Significant Accounting Policies - Schedule of Estimated Useful Lives of Assets (Detail)	12 Months Ended
	Dec. 31, 2020
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 Policies - Additional Information (Detail 1)	Dec. 31, 2020
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2018-01-01
Significant Accounting Policies [Line Items]
Revenue recognition performance obligation, expected time satisfaction period	12 months

Property and Equipment, Net - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property and equipment gross	$ 54,092	$ 53,371
Less accumulated depreciation	(24,894)	(17,003)
Property and equipment, net	29,198	36,368
Furniture and Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment gross	25,418	24,531
Software [Member]
Property Plant And Equipment [Line Items]
Property and equipment gross	684	524
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment gross	27,912	27,830
Fixed Assets in Progress [Member]
Property Plant And Equipment [Line Items]
Property and equipment gross	$ 78	$ 486

Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Abstract]
Depreciation expense	$ 8,114	$ 7,588

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
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	48,778,678	34,340,690
Common stock, shares outstanding	48,778,678	34,340,690

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued compensation	$ 9,003	$ 8,662
Accrued expenses related to CROs and CMOs	2,143	5,030
Accrued expenses and other current liabilities	825	2,493
Total accrued expenses and other current liabilities	$ 11,971	$ 16,185

Share Capital - Additional Information (Detail) $ / shares in Units, $ in Thousands	1 Months Ended			12 Months Ended
	Sep. 30, 2020 USD ($) $ / shares shares	Feb. 28, 2019 USD ($) shares	Jan. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) Vote $ / shares shares	Dec. 31, 2019 USD ($) $ / shares
Class of Stock [Line Items]
Net proceeds from sale of ordinary shares \| $				$ 93,744	$ 161,792
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
Common stock, authorized \| shares				0
Series A Preferred Shares [Member] \| Singapore [Member]
Class of Stock [Line Items]
Preferred stock, par value
Preferred stock, shares authorized \| shares				0
Follow-On Underwritten Public Offering [Member]
Class of Stock [Line Items]
Issue of ordinary shares, shares \| shares	8,333,334	592,500	3,950,000
Purchase price per share	$ 12.00		$ 38.00
Gross proceeds from sale of ordinary shares \| $	$ 100,000	$ 22,500	$ 150,100
Net proceeds from sale of ordinary shares \| $	$ 93,700		$ 161,800
At-The-Market Equity Program [Member]
Class of Stock [Line Items]
Issue of ordinary shares, shares \| shares				5,583,022
Net proceeds from sale of ordinary shares \| $				$ 59,882

Share-Based Compensation - Summary of Share Option Activity (Detail) - 2014 Plan [Member] $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) $ / shares shares
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Outstanding, Number of Shares, Beginning Balance \| shares	3,838,549
Granted, Number of Shares \| shares	1,024,010
Exercised, Number of Shares \| shares	(288,270)
Forfeited or cancelled, Number of Shares \| shares	(700,894)
Outstanding, Number of Shares, Ending Balance \| shares	3,873,395
Options exercisable, Number of Shares \| shares	2,783,041
Outstanding, Weighted Average Exercise Price, Beginning Balance \| $ / shares	$ 19.54
Granted, Weighted Average Exercise Price \| $ / shares	8.55
Exercised, Weighted Average Exercise Price \| $ / shares	2.57
Forfeited or cancelled, Weighted Average Exercise Price \| $ / shares	31.91
Outstanding, Weighted Average Exercise Price, Ending Balance \| $ / shares	15.67
Options exercisable, Weighted Average Exercise Price \| $ / shares	$ 16.37
Outstanding, Weighted Average Remaining Contractual Term	5 years 7 months 17 days
Options exercisable, Weighted Average Remaining Contractual Term	4 years 6 months 29 days
Outstanding, Aggregate Intrinsic Value \| $	$ 5,794
Options exercisable, Aggregate Intrinsic Value \| $	$ 5,792

Share-Based Compensation - Summary of RSU Activity (Detail) - RSUs [Member]	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Outstanding, Number of Shares, Beginning Balance \| shares	1,751,862
Granted, Number of Shares \| shares	77,125
Vested, Number of Shares \| shares	(208,123)
Forfeited, Number of Shares \| shares	(440,649)
Outstanding, Number of Shares, Ending Balance \| shares	1,180,215
Outstanding, Average Grant Date Fair Value, Beginning Balance \| $ / shares	$ 41.81
Granted, Average Grant Date Fair Value \| $ / shares	9.17
Vested, Average Grant Date Fair Value \| $ / shares	39.98
Forfeited, Average Grant Date Fair Value \| $ / shares	37.59
Outstanding, Average Grant Date Fair Value, Ending Balance \| $ / shares	$ 41.57

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, 2020	Dec. 31, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 14,296	$ 19,509
Research and Development Expenses [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	6,779	9,479
General and Administrative Expenses [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 7,517	$ 10,030

Leases - Additional Information (Detail) - USD ($)	12 Months Ended	27 Months Ended
Leases - Additional Information (Detail) - USD ($)	Dec. 31, 2020	Dec. 31, 2018	Oct. 21, 2021	Dec. 31, 2019	Sep. 26, 2016	Apr. 30, 2015
Operating Leased Assets [Line Items]
Restricted cash	$ 3,651,000			$ 3,647,000
Future minimum lease payments	38,385,000
Future minimum lease payments, due in 2021	$ 6,021,000
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	$ 2,700,000			2,600,000
Lease renewal term					5 years
Lexington, Massachusetts [Member] \| Maximum [Member]
Operating Leased Assets [Line Items]
Tenant improvement allowances received		$ 11,400,000
Cambridge, Massachusetts [Member]
Operating Leased Assets [Line Items]
Lease agreement term						7 years 6 months
Restricted cash	$ 1,000,000.0			$ 1,000,000.0
Lease renewal term						5 years
Lease option to extend description	five-year renewal option to extend the lease
Option to extend the lease	true
Description of additional lease space expected to commence	The lease for the additional space is expected to commence on October 1, 2021 with a term of five years.
Cambridge, Massachusetts [Member] \| Forecast [Member]
Operating Leased Assets [Line Items]
Term of additional lease space expected to commence			5 years
Future minimum lease payments			$ 5,400,000
Future minimum lease payments, due in 2021			300,000
Future minimum lease payments, due in beyond 2021			$ 5,100,000

Leases - Summary of Lease Costs Recognized and Other Information Pertaining to Operating Leases (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lease cost
Operating lease cost	$ 4,472	$ 4,472
Total lease cost	4,472	4,472
Other information
Operating cash flows used for operating leases	$ 5,846	$ 5,675
Weighted average remaining lease term	6 years 4 months 24 days	7 years 3 months 18 days
Weighted average discount rate	8.50%	8.50%

Leases - Schedule of Future Minimum Rental Payments for Operating Leases Under Topic 842 (Detail) $ in Thousands	Dec. 31, 2020 USD ($)
Operating Lease Liabilities, Payments Due [Abstract]
2021	$ 6,021
2022	6,201
2023	5,236
2024	5,002
2025	5,152
Thereafter	10,773
Total lease payments	38,385
Less: imputed interest	(9,080)
Total operating lease liabilities	$ 29,305

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, 2020	Dec. 31, 2019
Numerator:
Net loss attributable to ordinary shareholders	$ (149,910)	$ (193,638)
Denominator:
Weighted-average ordinary shares outstanding	39,227,618	33,866,487
Net loss per share, basic and diluted	$ (3.82)	$ (5.72)

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, 2020	Dec. 31, 2019
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	3,873,395	3,838,549
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	1,180,215	1,751,862
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 - Deferred Components of Benefit (Provision), Net for Income Taxes (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Current benefit (provision), net for income taxes:
Total current benefit (provision), net for income taxes	$ 841,000
Deferred benefit (provision), net for income taxes:
Total benefit (provision), net for income taxes	841,000	$ 0
Singapore [Member]
Deferred benefit (provision), net for income taxes:
Total benefit (provision), net for income taxes	0	$ 0
Rest Of World [Member]
Current benefit (provision), net for income taxes:
Total current benefit (provision), net for income taxes	$ 841,000

Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 133,841	$ 89,585
Federal and state tax credits	36,151	31,336
Share-based compensation	5,880	6,342
Accumulated amortization	962	11,169
Operating lease liabilities	8,006	8,892
Deferred revenue	13,956	14,299
Other	1,146	424
Total deferred tax assets	199,942	162,047
Valuation allowance	(195,381)	(156,680)	$ (99,438)
Net deferred tax assets	4,561	5,367
Deferred tax liabilities:
Operating lease right-of-use assets	(4,435)	(4,945)
Accumulated depreciation	(117)	(422)
Other	(9)
Total deferred tax liabilities	$ (4,561)	$ (5,367)

Income Taxes - Summary of Valuation Allowance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Deferred Tax Assets Net Of Valuation Allowance [Abstract]
Balance at beginning of year	$ 156,680	$ 99,438
Increase in valuation allowance	38,653	57,235
Effect of foreign currency translation	48	7
Balance at end of year	$ 195,381	$ 156,680

Income Taxes - Summary of Activity in Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Reconciliation Of Unrecognized Tax Benefits Excluding Amounts Pertaining To Examined Tax Returns Roll Forward
Unrecognized tax benefit at the beginning of the year	$ 16,682	$ 10,219
Tax positions related to prior years	(310)	(14)
Tax positions related to statute lapse	(313)	(23)
Tax positions related to the current year	2,357	6,500
Unrecognized tax benefit at the end of the year	$ 18,416	$ 16,682

Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
401(k) Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Discretionary contributions to defined contribution pension plan	$ 0.9	$ 1.0

Related Parties - Additional Information (Detail) - Scientific Advisor [Member] - Consulting Agreement [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Related Party Transaction [Line Items]
Consulting agreement termination notice period	14 days
Consulting service expenses		$ 13