0001564590-20-023860 | 10-Q | XBRL Viewer

Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2020	May 01, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Trading Symbol	WVE
Entity Registrant Name	WAVE LIFE SCIENCES LTD.
Entity Incorporation, State or Country Code	U0
Entity Central Index Key	0001631574
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Quarterly Report	true
Document Transition Report	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		34,892,550
Entity Shell Company	false
Entity Tax Identification Number	00-0000000
Entity File Number	001-37627
Entity Address, Address Line One	7 Straits View #12-00
Entity Address, Address Line Two	Marina One East Tower
Entity Address, Country	SG
Entity Address, Postal Zip Code	018936
City Area Code	+65
Local Phone Number	6236 3388
Title of 12(b) Security	$0 Par Value Ordinary Shares
Security Exchange Name	NASDAQ

Unaudited Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 120,949	$ 147,161
Current portion of accounts receivable		20,000
Prepaid expenses	9,999	9,626
Other current assets	18,843	8,689
Total current assets	149,791	185,476
Long-term assets:
Accounts receivable, net of current portion	30,000	30,000
Property and equipment, net	34,986	36,368
Operating lease right-of-use assets	17,659	18,101
Restricted cash	3,649	3,647
Other assets	2,487	10,658
Total long-term assets	88,781	98,774
Total assets	238,572	284,250
Current liabilities:
Accounts payable	16,486	9,073
Accrued expenses and other current liabilities	10,994	16,185
Current portion of deferred revenue	88,044	89,652
Current portion of operating lease liability	3,357	3,243
Total current liabilities	118,881	118,153
Long-term liabilities:
Deferred revenue, net of current portion	60,913	63,466
Operating lease liability, net of current portion	28,425	29,304
Other liabilities	1,621	1,721
Total long-term liabilities	90,959	94,491
Total liabilities	209,840	212,644
Series A preferred shares, no par value; 3,901,348 shares issued and outstanding at March 31, 2020 and December 31, 2019	7,874	7,874
Shareholders’ equity:
Ordinary shares, no par value; 34,601,582 and 34,340,690 shares issued and outstanding at March 31, 2020 and December 31, 2019, respectively	540,161	539,547
Additional paid-in capital	61,276	57,277
Accumulated other comprehensive income	273	267
Accumulated deficit	(580,852)	(533,359)
Total shareholders’ equity	20,858	63,732
Total liabilities, Series A preferred shares and shareholders’ equity	$ 238,572	$ 284,250

Unaudited Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 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	34,601,582	34,340,690
Common stock, shares outstanding	34,601,582	34,340,690

Unaudited Consolidated Statements of Operations and Comprehensive Loss - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenue	$ 4,161,000	$ 3,026,000
Operating expenses:
Research and development	41,158,000	40,113,000
General and administrative	12,996,000	10,901,000
Total operating expenses	54,154,000	51,014,000
Loss from operations	(49,993,000)	(47,988,000)
Other income, net:
Dividend income	385,000	1,424,000
Interest income, net	3,000	11,000
Other income (expense), net	2,112,000	2,353,000
Total other income, net	2,500,000	3,788,000
Loss before income taxes	(47,493,000)	(44,200,000)
Income tax provision	0	0
Net loss	$ (47,493,000)	$ (44,200,000)
Net loss per share attributable to ordinary shareholders—basic and diluted	$ (1.38)	$ (1.36)
Weighted-average ordinary shares used in computing net loss per share attributable to ordinary shareholders—basic and diluted	34,461,505	32,597,158
Other comprehensive income (loss):
Net loss	$ (47,493,000)	$ (44,200,000)
Foreign currency translation	6,000	97,000
Comprehensive loss	$ (47,487,000)	$ (44,103,000)

Unaudited Consolidated Statements of Series A Preferred Shares and Shareholders' Equity - USD ($) $ in Thousands	Total	At-The-Market Equity Program [Member]	Series A Preferred Shares [Member]	Ordinary Shares [Member]	Ordinary Shares [Member] At-The-Market Equity Program [Member]	Additional Paid-In-Capital [Member]	Accumulated Other Comprehensive Income [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	161,785			$ 161,785
Issue of ordinary shares, shares				4,542,500
Share-based compensation	4,345					4,345
Vesting of RSUs, shares				110,187
Option exercises	1,481			$ 1,481
Option exercises, shares				130,522
Other comprehensive income	97						97
Net loss	(44,200)							(44,200)
Ending balance at Mar. 31, 2019	196,856			$ 538,414		42,113	250	(383,921)
Ending balance, shares at Mar. 31, 2019				34,255,406
Temporary equity, Ending balance at Mar. 31, 2019			$ 7,874
Temporary equity, Ending balance, shares at Mar. 31, 2019			3,901,348
Beginning balance at Dec. 31, 2019	63,732			$ 539,547		57,277	267	(533,359)
Beginning balance, shares at Dec. 31, 2019				34,340,690
Temporary equity, Beginning balance at Dec. 31, 2019	$ 7,874		$ 7,874
Temporary equity, Beginning balance, shares at Dec. 31, 2019	3,901,348		3,901,348
Issuance of ordinary shares		$ 604			$ 604
Issue of ordinary shares, shares					59,690
Share-based compensation	$ 3,999					3,999
Vesting of RSUs, shares				198,202
Option exercises	10			$ 10
Option exercises, shares				3,000
Other comprehensive income	6						6
Net loss	(47,493)							(47,493)
Ending balance at Mar. 31, 2020	20,858			$ 540,161		$ 61,276	$ 273	$ (580,852)
Ending balance, shares at Mar. 31, 2020				34,601,582
Temporary equity, Ending balance at Mar. 31, 2020	$ 7,874		$ 7,874
Temporary equity, Ending balance, shares at Mar. 31, 2020	3,901,348		3,901,348

Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities
Net loss	$ (47,493)	$ (44,200)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of right-of-use assets	442	381
Depreciation of property and equipment	2,039	1,783
Share-based compensation expense	3,999	4,345
Changes in operating assets and liabilities:
Accounts receivable	20,000
Prepaid expenses	(373)	(1,090)
Other assets	(1,983)	(2,124)
Accounts payable	7,336	783
Accrued expenses and other current liabilities	(5,191)	(6,467)
Deferred revenue	(4,161)	(3,026)
Operating lease liabilities	(765)	(663)
Other non-current liabilities	(100)	(103)
Net cash used in operating activities	(26,250)	(50,381)
Cash flows from investing activities
Purchases of property and equipment	(580)	(508)
Net cash used in investing activities	(580)	(508)
Cash flows from financing activities
Proceeds from issuance of ordinary shares, net of offering costs		162,065
Proceeds from the exercise of share options	10	1,481
Net cash provided by financing activities	614	163,546
Effect of foreign exchange rates on cash, cash equivalents and restricted cash	6	97
Net increase (decrease) in cash, cash equivalents and restricted cash	(26,210)	112,754
Cash, cash equivalents and restricted cash, beginning of period	150,808	178,444
Cash, cash equivalents and restricted cash, end of period	124,598	291,198
Supplemental disclosure of cash flow information:
Deferred follow-on offering costs in accounts payable and accrued expenses at period end		$ 280
At-The-Market Equity Program [Member]
Cash flows from financing activities
Proceeds from issuance of ordinary shares, net of offering costs	$ 604

The Company

3 Months Ended

Mar. 31, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

The Company

1. THE COMPANY

Organization

Wave Life Sciences Ltd. (together with its subsidiaries, “Wave” or the “Company”) is a clinical-stage genetic medicines company committed to delivering life-changing treatments for people battling devastating diseases. PRISM, Wave’s proprietary discovery and drug development platform, enables Wave to target genetically defined diseases with stereopure oligonucleotides across multiple therapeutic modalities.

The Company was incorporated in Singapore on July 23, 2012 and has its principal U.S. office in Cambridge, Massachusetts. The Company was incorporated with the purpose of combining two commonly held companies, Wave Life Sciences USA, Inc. (“Wave USA”), a Delaware corporation (formerly Ontorii, Inc.), and Wave Life Sciences Japan, Inc. (“Wave Japan”), a company organized under the laws of Japan (formerly Chiralgen., Ltd.), which occurred on September 13, 2012. On May 31, 2016, Wave Life Sciences Ireland Limited (“Wave Ireland”) was formed as a wholly-owned subsidiary of Wave Life Sciences Ltd. On April 3, 2017, Wave Life Sciences UK Limited (“Wave UK”) was formed as a wholly-owned subsidiary of Wave Life Sciences Ltd.

The Company’s primary activities since inception have been developing PRISM to design, develop and commercialize oligonucleotide therapeutics, advancing the Company’s neurology business, building the Company’s research and development activities in ophthalmology and hepatic, advancing programs into the clinic, furthering clinical development of such clinical-stage programs, building the Company’s intellectual property, and assuring adequate capital to support these activities.

Liquidity

Since its inception, the Company has not generated any product revenue and has incurred recurring net losses. To date, the Company has primarily funded its operations through private placements of debt and equity securities, public offerings of its ordinary shares and collaborations with third parties. Until the Company can generate significant revenue from product sales, if ever, the Company expects to continue to finance operations through a combination of public or private equity or debt financings or other sources, which may include collaborations with third parties. Adequate additional financing may not be available to the Company on acceptable terms, or at all. The inability to raise capital as and when needed would have a negative impact on the Company’s financial condition and ability to pursue its business strategy.

As of March 31, 2020, the Company had cash and cash equivalents of $120.9 million. The Company expects that its existing cash and cash equivalents will be sufficient to fund its operations for at least the next twelve months. The Company has based this expectation on assumptions that may prove to be incorrect, and the Company may use its available capital resources sooner than it currently expects. If the Company’s anticipated operating results are not achieved in future periods, planned expenditures may need to be further reduced in order to extend the time period over which the then-available resources would be able to fund the Company’s operations. In addition, the Company may elect to raise additional funds before it needs them if the conditions for raising capital are favorable due to market conditions or strategic considerations, even if the Company expects it has sufficient funds for its current or future operating plans.

Risks and Uncertainties

The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, maintaining internal manufacturing capabilities, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. The Company’s therapeutic programs will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval, prior to commercialization of any product candidates. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance-reporting capabilities. There can be no assurance that the Company’s research and development efforts will be successful, that adequate protection for the Company’s intellectual property will be obtained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies.

COVID-19 Global Pandemic

In December 2019, a novel strain of coronavirus was first identified in Wuhan, Hubei Province, China. Since that time, multiple other countries throughout the world and their economies have been effectively shut down and significantly affected by the spread of the virus. To date, responsive measures such as social distancing, work-from-home policies, travel bans and quarantines have been implemented in many countries throughout the world.

The Company is closely monitoring developments related to COVID-19, which was declared a pandemic by the World Health Organization on March 11, 2020. In response to this global pandemic, the Company has concentrated its efforts to remain focused on the health and safety of its employees and patients, while maintaining business continuity and honoring its commitment to deliver life-changing treatments for people battling devastating diseases.

The COVID-19 global pandemic is evolving rapidly and its impact on the Company is highly uncertain and subject to change. The Company does not yet know the full extent of potential delays or long-term impacts on its business, its clinical trials, healthcare systems or the global economy. These impacts are highly uncertain and cannot be predicted with confidence, such as the ultimate geographic spread of the disease, the duration of the outbreak, travel restrictions and actions to contain the outbreak or treat its impact, such as social distancing and quarantines or lock-downs, business closures or business disruptions and the effectiveness of actions taken to contain and treat the disease. These effects may materially adversely affect the Company’s business, financial condition, results of operations, and prospects.

Basis of Presentation

The Company has prepared the accompanying consolidated financial statements in conformity with generally accepted accounting principles in the United States (“U.S. GAAP”) and in U.S. dollars.

Significant Accounting Policies

3 Months Ended

Mar. 31, 2020

Accounting Policies [Abstract]

Significant Accounting Policies

2. SIGNIFICANT ACCOUNTING POLICIES

The significant accounting policies described in the Company’s audited financial statements as of and for the year ended December 31, 2019, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019, filed with the Securities and Exchange Commission (“SEC”) on March 2, 2020, as amended (the “2019 Annual Report on Form 10-K”), have had no material changes during the three months ended March 31, 2020.

Unaudited Interim Financial Data

The accompanying interim consolidated balance sheet as of March 31, 2020, the related interim consolidated statements of operations and comprehensive loss for the three months ended March 31, 2020 and 2019, the consolidated statements of Series A preferred shares and shareholders’ equity for the three months ended March 31, 2020 and 2019, the consolidated statements of cash flows for the three months ended March 31, 2020 and 2019, and the related interim information contained within the notes to the consolidated financial statements have been prepared in accordance with the rules and regulations of the SEC for interim financial information. Accordingly, they do not include all of the information and the notes required by U.S. GAAP for complete financial statements. The financial data and other information disclosed in these notes related to the three months ended March 31, 2020 and 2019 are unaudited. In the opinion of management, the unaudited interim consolidated financial statements reflect all adjustments, consisting of normal and recurring adjustments, necessary for the fair presentation of the Company’s financial position and results of operations for the three months ended March 31, 2020 and 2019. The results of operations for the interim periods are not necessarily indicative of the results to be expected for the year ending December 31, 2020 or any other interim period or future year or period.

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.

Reclassifications

The Company has reclassified certain prior period financial statement amounts to conform to its current period presentation. These reclassifications have not changed the results of operations of prior periods.

Recently Issued Accounting Pronouncements

The recently issued accounting pronouncements described in the Company’s audited financial statements as of and for the year ended December 31, 2019, and the notes thereto, which are included in the 2019 Annual Report on Form 10-K, have had no material changes during the three months ended March 31, 2020.

Other Current Assets

3 Months Ended

Mar. 31, 2020

Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]

Other Current Assets

3. OTHER CURRENT ASSETS

Other current assets consist of the following:

	March 31, 2020		December 31, 2019
	(in thousands)
Refundable tax credits receivable	$	18,692	$	8,205
Dividend income receivable		104		200
Other current assets		47		284
Total other current assets	$	18,843	$	8,689

Share-Based Compensation

3 Months Ended

Mar. 31, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Share-Based Compensation

4. SHARE-BASED COMPENSATION

The Wave Life Sciences Ltd. 2014 Equity Incentive Plan, as amended (the “2014 Plan”), authorizes the board of directors or a committee of the board of directors to, among other things, grant non-qualified share options, restricted awards, which includes restricted shares, time-based restricted share units (“RSUs”) and performance-based restricted share units (“PSUs”) to eligible employees and directors of the Company. Options generally vest over periods of one to four years, and any 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. RSUs generally vest over a period of one to four years. PSUs vest upon the achievement of certain milestones. Any RSUs or PSUs that are forfeited are available to be granted again.

During the three months ended March 31, 2020, the Company granted 701,685 options and 14,750 RSUs to employees.

As of March 31, 2020, 878,110 ordinary shares remained available for future grant under the 2014 Plan.

Employee Share Purchase Plan

At the 2019 Annual General Meeting, the Company’s board of directors and the Company’s shareholders approved the 2019 Employee Share Purchase Plan (“ESPP”). As of March 31, 2020, there were 1,000,000 ordinary shares available for issuance under the ESPP. The 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 approximately 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 three months ended March 31, 2020, no shares were issued under the ESPP and the earliest that shares would be issued under the ESPP is July 14, 2020.

Collaboration Agreements

3 Months Ended

Mar. 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 may 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 is responsible to use its commercially reasonable efforts to advance up to five programs through to the selection of clinical candidates. At that stage, Pfizer may 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 provides 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.

Through March 31, 2020, the Company had recognized revenue of $18.3 million as collaboration revenue in the Company’s consolidated statements of operations and comprehensive loss under the Pfizer Collaboration Agreement. During the three months ended March 31, 2020 and 2019, the Company recognized revenue of approximately $1.3 million and $0.6 million, respectively, in the Company’s consolidated statements of operations and comprehensive loss under the Pfizer Collaboration Agreement. The aggregate amount of the transaction price allocated to the Company’s partially unsatisfied performance obligations and recorded in deferred revenue at March 31, 2020 is $0.2 million, all of which is included in current liabilities. The Company expects to recognize this amount according to FTE hours incurred, over the remaining research term, which is one month as of March 31, 2020.

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 (“JSC”) in which both parties are represented equally. The JSC 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 March 31, 2020, the Company had recognized revenue of approximately $21.3 million as collaboration revenue in the Company’s consolidated statements of operations and comprehensive loss under the Takeda Collaboration Agreement. During the three months ended March 31, 2020 and 2019, the Company recognized revenue of $2.9 million and $2.5 million, respectively, in the Company’s consolidated statements of operations and comprehensive loss under the Takeda Collaboration Agreement. The aggregate amount of the transaction price allocated to the Company’s unsatisfied and partially unsatisfied performance obligations and recorded in deferred revenue at March 31, 2020 is $148.7 million, of which $87.8 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 March 31, 2020 is $30.0 million, all of which is included in long-term assets.

Net Loss Per Ordinary Share

3 Months Ended

Mar. 31, 2020

Earnings Per Share [Abstract]

Net Loss Per Ordinary Share

6. NET LOSS PER ORDINARY SHARE

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.

Basic loss per share is computed by dividing net loss attributable to ordinary shareholders by the weighted-average number of ordinary shares.

The Company’s potentially dilutive shares, which include outstanding share options to purchase ordinary shares, RSUs, PSUs and Series A preferred shares, are considered to be ordinary share equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive.

The following ordinary share equivalents, presented based on amounts outstanding at each period end, were excluded from the calculation of diluted net loss per share attributable to ordinary shareholders for the periods indicated because including them would have had an anti-dilutive effect:

	As of March 31,
	2020		2019
Options to purchase ordinary shares		4,320,605		3,853,542
RSUs and PSUs		1,272,350		1,674,124
Series A preferred shares		3,901,348		3,901,348

Additionally, 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.

Income Taxes

3 Months Ended

Mar. 31, 2020

Income Tax Disclosure [Abstract]

Income Taxes

7. INCOME TAXES

During the three months ended March 31, 2020 and 2019, the Company recorded no income tax provision.

The Company maintained a full valuation allowance for the three months ended March 31, 2020 and 2019 in all jurisdictions due to uncertainty regarding future taxable income.

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.

Geographic Data

3 Months Ended

Mar. 31, 2020

Geographic Data [Abstract]

Geographic Data

8. GEOGRAPHIC DATA

Substantially all of the Company’s long-lived assets were located in the United States as of March 31, 2020 and December 31, 2019.

Related Parties

3 Months Ended

Mar. 31, 2020

Related Parties

9. RELATED PARTIES

The Company had the following related party transaction for the periods presented in the accompanying consolidated financial statements, which has not otherwise been discussed in these notes to the consolidated financial statements:

•

In 2012, the Company entered into a consulting agreement for scientific advisory services with Dr. Gregory L. Verdine, one of the Company’s founders and a member of the Company’s board of directors. The consulting agreement does not have a specific term and may be terminated by either party upon 14 days’ prior written notice. Pursuant to the consulting agreement, the Company pays Dr. Verdine approximately $13 thousand per month, plus reimbursement for certain expenses.

February 2020 Cost Reduction Plan

3 Months Ended

Mar. 31, 2020

Restructuring And Related Activities [Abstract]

February 2020 Cost Reduction Plan

10. FEBRUARY 2020 COST REDUCTION PLAN

On February 6, 2020, the Company implemented a plan to reduce operating costs and better align its workforce with the needs of its business following the Company’s December 16, 2019 announcement of its decision to discontinue the suvodirsen program for patients with Duchenne muscular dystrophy (“DMD”) and to cease development of the Company’s other DMD programs. Under this cost reduction plan, the Company reduced its workforce by approximately 22%. The Company incurred a one-time restructuring charge of approximately $3.4 million, of which $2.5 million was included in research and development expenses and $0.9 million was included in general and administrative expenses in the Company’s consolidated statements of operations and comprehensive loss, including employee severance, benefits and related termination costs, during the three months ended March 31, 2020.

During the three months ended March 31, 2020, the Company paid approximately $2.1 million of these restructuring expenses. The remaining payments of $1.3 million will be paid through March 31, 2021.

	Accrued Restructuring Expenses at January 1, 2020		Expenses		Less: Payments			Accrued Restructuring Expenses at March 31, 2020
	(in thousands)
Severance, benefits and related costs due to workforce reduction	$	—	$	3,385	$	(2,096	)	$	1,289
Total	$	—	$	3,385	$	(2,096	)	$	1,289

Significant Accounting Policies (Policies)	3 Months Ended
Significant Accounting Policies (Policies)	Mar. 31, 2020
Accounting Policies [Abstract]
Unaudited Interim Financial Data	Unaudited Interim Financial Data The accompanying interim consolidated balance sheet as of March 31, 2020, the related interim consolidated statements of operations and comprehensive loss for the three months ended March 31, 2020 and 2019, the consolidated statements of Series A preferred shares and shareholders’ equity for the three months ended March 31, 2020 and 2019, the consolidated statements of cash flows for the three months ended March 31, 2020 and 2019, and the related interim information contained within the notes to the consolidated financial statements have been prepared in accordance with the rules and regulations of the SEC for interim financial information. Accordingly, they do not include all of the information and the notes required by U.S. GAAP for complete financial statements. The financial data and other information disclosed in these notes related to the three months ended March 31, 2020 and 2019 are unaudited. In the opinion of management, the unaudited interim consolidated financial statements reflect all adjustments, consisting of normal and recurring adjustments, necessary for the fair presentation of the Company’s financial position and results of operations for the three months ended March 31, 2020 and 2019. The results of operations for the interim periods are not necessarily indicative of the results to be expected for the year ending December 31, 2020 or any other interim period or future year or period.
Principles of Consolidation	Principles of Consolidation The Company’s consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Reclassifications	Reclassifications The Company has reclassified certain prior period financial statement amounts to conform to its current period presentation. These reclassifications have not changed the results of operations of prior periods.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements The recently issued accounting pronouncements described in the Company’s audited financial statements as of and for the year ended December 31, 2019, and the notes thereto, which are included in the 2019 Annual Report on Form 10-K, have had no material changes during the three months ended March 31, 2020.

Other Current Assets (Tables)

3 Months Ended

Mar. 31, 2020

Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]

Schedule of Other Current Assets

Other current assets consist of the following:

	March 31, 2020		December 31, 2019
	(in thousands)
Refundable tax credits receivable	$	18,692	$	8,205
Dividend income receivable		104		200
Other current assets		47		284
Total other current assets	$	18,843	$	8,689

Net Loss Per Ordinary Share (Tables)

3 Months Ended

Mar. 31, 2020

Earnings Per Share [Abstract]

Anti-Dilutive Shares Excluded from Calculation of Diluted Net Loss Per Ordinary Share

	As of March 31,
	2020		2019
Options to purchase ordinary shares		4,320,605		3,853,542
RSUs and PSUs		1,272,350		1,674,124
Series A preferred shares		3,901,348		3,901,348

February 2020 Cost Reduction Plan (Tables)

3 Months Ended

Mar. 31, 2020

Restructuring And Related Activities [Abstract]

Summary of Accrued Restructuring Expenses

	Accrued Restructuring Expenses at January 1, 2020		Expenses		Less: Payments			Accrued Restructuring Expenses at March 31, 2020
	(in thousands)
Severance, benefits and related costs due to workforce reduction	$	—	$	3,385	$	(2,096	)	$	1,289
Total	$	—	$	3,385	$	(2,096	)	$	1,289

The Company - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Cash and cash equivalents	$ 120,949	$ 147,161

Other Current Assets - Schedule of Other Current Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Refundable tax credits receivable	$ 18,692	$ 8,205
Dividend income receivable	104	200
Other current assets	47	284
Total other current assets	$ 18,843	$ 8,689

Share-Based Compensation - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2020 shares
Options [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Options granted to employees	701,685
RSUs to Employees [Member}
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Shares granted to employees	14,750
ESPP [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Number of shares available for issuance	1,000,000
Share purchase price at equal to fair market value percentage	85.00%
Number of shares issued	0
2014 Plan [Member]
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Ordinary shares available for future grant	878,110
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] \| RSUs to Employees [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] \| RSUs to Employees [Member}
Share-based Compensation Arrangement By Share-based Payment Award [Line Items]
Vesting period	4 years

Collaboration Agreements - Additional Information (Detail)			1 Months Ended			3 Months Ended		26 Months Ended	47 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	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Equity investment aggregate purchase price							$ 161,785,000
Proceeds from issuance of ordinary shares, net of offering costs							162,065,000
Collaboration revenue recognized						$ 4,161,000	3,026,000
Collaboration and license agreement, deferred revenue current						$ 88,044,000		$ 88,044,000	$ 88,044,000	$ 89,652,000
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 is responsible to use its commercially reasonable efforts to advance up to five programs through to the selection of clinical candidates. At that stage, Pfizer may 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						$ 1,300,000	600,000		18,300,000
Collaboration and license agreement, deferred revenue						$ 200,000		200,000	200,000
Remaining research term						1 month
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, deferred revenue						$ 148,700,000		148,700,000	148,700,000
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						2,900,000	$ 2,500,000	21,300,000
Collaboration and license agreement, deferred revenue current						87,800,000		87,800,000	87,800,000
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

Net Loss Per Ordinary Share - Anti-Dilutive Shares Excluded from Calculation of Diluted Net Loss Per Ordinary Share (Detail) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 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	4,320,605	3,853,542
RSUs and PSUs [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from calculation of diluted net loss per share	1,272,350	1,674,124
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 - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income tax benefit (provision)	$ 0	$ 0

Related Parties - Additional Information (Detail) - Scientific Advisor [Member] - Consulting Agreement [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($)
Related Party Transaction [Line Items]
Consulting agreement termination notice period	14 days
Consulting service expenses	$ 13

February 2020 Cost Reduction Plan - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended
	Feb. 06, 2020	Mar. 31, 2020
Restructuring Cost And Reserve [Line Items]
Percentage of reduction in workforce	22.00%
Restructuring Charges		$ 3,385
Restructuring expenses		2,096
Restructuring expenses remaining		1,300
Research and Development Expenses [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring Charges		2,500
General and Administrative Expenses [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring Charges		$ 900

February 2020 Cost Reduction Plan - Summary of Accrued Restructuring Expenses (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($)
Restructuring Cost And Reserve [Line Items]
Accrued Restructuring Expenses	$ 0
Expenses	3,385
Less: Payments	(2,096)
Accrued Restructuring Expenses	1,289
Severance, Benefits and Related Costs Due to Workforce Reduction [Member]
Restructuring Cost And Reserve [Line Items]
Accrued Restructuring Expenses	0
Expenses	3,385
Less: Payments	(2,096)
Accrued Restructuring Expenses	$ 1,289