PASSAGE BIO, INC., 10-Q filed on 5/11/2023
Quarterly Report
v3.23.1
Document and Entity Information - shares
3 Months Ended
Mar. 31, 2023
May 09, 2023
Document and Entity Information    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2023  
Document Transition Report false  
Entity File Number 001-39231  
Entity Registrant Name PASSAGE BIO, INC.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 82-2729751  
Entity Address, Address Line One One Commerce Square  
Entity Address, Address Line Two 2005 Market Street, 39th Floor  
Entity Address, City or Town Philadelphia  
Entity Address, State or Province PA  
Entity Address, Postal Zip Code 19103  
City Area Code 267  
Local Phone Number 866-0311  
Title of 12(b) Security Common Stock  
Trading Symbol PASG  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   54,632,940
Entity Central Index Key 0001787297  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2023  
Document Fiscal Period Focus Q1  
Amendment Flag false  
v3.23.1
Balance Sheets - USD ($)
$ in Thousands
Mar. 31, 2023
Dec. 31, 2022
Current assets:    
Cash and cash equivalents $ 33,372 $ 34,601
Marketable securities 134,402 155,009
Prepaid expenses and other current assets 1,685 926
Prepaid research and development 2,162 6,508
Total current assets 171,621 197,044
Property and equipment, net 21,599 22,515
Right of use assets - operating leases 19,590 19,723
Other assets 433 4,267
Total assets 213,243 243,549
Current liabilities:    
Accounts payable 3,033 4,065
Accrued expenses and other current liabilities 10,907 11,011
Operating lease liabilities 3,303 3,275
Total current liabilities 17,243 18,351
Operating lease liabilities - noncurrent 23,649 23,832
Other liabilities 2,000  
Total liabilities 42,892 42,183
Commitments and Contingencies (note 9)
Stockholders' equity:    
Common stock, $0.0001 par value: 300,000,000 shares authorized; 54,626,690 shares issued and outstanding at March 31, 2023 and 54,614,690 shares issued and outstanding at December 31, 2022 5 5
Additional paid-in capital 697,517 694,733
Accumulated other comprehensive income (loss) (427) (966)
Accumulated deficit (526,744) (492,406)
Total stockholders' equity 170,351 201,366
Total liabilities and stockholders' equity $ 213,243 $ 243,549
v3.23.1
Balance Sheets (Parenthetical) - $ / shares
Mar. 31, 2023
Dec. 31, 2022
Balance Sheets    
Common stock, par value (in dollars per share) $ 0.0001 $ 0.0001
Common stock, shares authorized 300,000,000 300,000,000
Common stock, shares issued 54,626,690 54,614,690
Common stock, shares outstanding 54,626,690 54,614,690
v3.23.1
Statements of Operations and Comprehensive Loss - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Operating expenses:    
Research and development $ 16,836 $ 26,213
Acquired in-process research and development   1,500
General and administrative 19,047 15,099
Loss from operations (35,883) (42,812)
Other income (expense), net 1,545 1
Net loss $ (34,338) $ (42,811)
Per share information:    
Net loss per share of common stock, basic $ (0.63) $ (0.79)
Net loss per share of common stock, diluted $ (0.63) $ (0.79)
Weighted average common shares outstanding, basic 54,618,799 54,275,751
Weighted average common shares outstanding, diluted 54,618,799 54,275,751
Comprehensive loss:    
Net loss $ (34,338) $ (42,811)
Unrealized gain (loss) on marketable securities 539 (921)
Comprehensive loss $ (33,799) $ (43,732)
v3.23.1
Statements of Stockholders' Equity - USD ($)
$ in Thousands
Common stock
Additional paid-in capital
Accumulated other comprehensive income (loss)
Accumulated deficit
Total
Balance at Beginning of period at Dec. 31, 2021 $ 5 $ 675,346 $ (413) $ (356,281) $ 318,657
Balance at Beginning of period (in shares) at Dec. 31, 2021 54,244,996        
Stockholders' equity          
Exercise of stock options and vesting of restricted stock units   49     49
Exercise of stock options and vesting of restricted stock units (in shares) 62,695        
Unrealized gain (loss) on marketable securities     (921)   (921)
Share-based compensation expense   6,337     6,337
Net loss       (42,811) (42,811)
Balance at end of period at Mar. 31, 2022 $ 5 681,732 (1,334) (399,092) 281,311
Balance at end of period (in shares) at Mar. 31, 2022 54,307,691        
Balance at Beginning of period at Dec. 31, 2022 $ 5 694,733 (966) (492,406) 201,366
Balance at Beginning of period (in shares) at Dec. 31, 2022 54,614,690        
Stockholders' equity          
Exercise of stock options and vesting of restricted stock units (in shares) 12,000        
Unrealized gain (loss) on marketable securities     539   539
Share-based compensation expense   2,784     2,784
Net loss       (34,338) (34,338)
Balance at end of period at Mar. 31, 2023 $ 5 $ 697,517 $ (427) $ (526,744) $ 170,351
Balance at end of period (in shares) at Mar. 31, 2023 54,626,690        
v3.23.1
Statements of Cash Flows - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Cash flows used in operating activities:    
Net loss $ (34,338) $ (42,811)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:    
Acquired in-process research and development   1,500
Depreciation and amortization 978 883
Share-based compensation 2,784 6,337
Amortization of premium and discount on marketable securities, net (98) 875
Changes in operating assets and liabilities:    
Prepaid expenses and other current assets, and other assets 3,075 (624)
Prepaid research and development 4,346 (5,509)
Right of use assets and operating lease liabilities (21) 418
Accounts payable (1,039) (957)
Accrued expenses and other current and noncurrent liabilities 1,867 (4,823)
Net cash provided by (used in) operating activities (22,446) (44,711)
Cash flows provided by (used in) investing activities:    
Purchases of marketable securities (51,396) (37,402)
Sales or maturities of marketable securities 72,639 56,938
Purchases of technology licenses   (1,500)
Purchases of property and equipment (26) (725)
Net cash provided by (used in) investing activities 21,217 17,311
Cash flows provided by (used in) financing activities:    
Proceeds from the exercise of stock options   49
Net cash provided by (used in) financing activities   49
Net increase (decrease) in cash and cash equivalents (1,229) (27,351)
Cash and cash equivalents at beginning of period 34,601 128,965
Cash and cash equivalents at end of period 33,372 101,614
Supplemental disclosure of non-cash investing and financing activities:    
Unrealized gain (loss) on marketable securities 539 (921)
Property and equipment in accounts payable and accrued expenses and other current liabilities $ 36 644
Right of use assets recognized upon the adoption of Topic 842   (20,375)
Operating lease liabilities recognized upon the adoption of Topic 842   $ 27,296
v3.23.1
Nature of Operations
3 Months Ended
Mar. 31, 2023
Nature of Operations  
Nature of Operations

1. Nature of Operations

Passage Bio, Inc., or the Company, a Delaware corporation incorporated in July 2017, is a clinical stage genetic medicines company focused on developing transformative therapies for central nervous system, or CNS, disorders, with limited or no approved treatment options. The Company has a strategic research collaboration with the Trustees of the University of Pennsylvania’s, or Penn, Gene Therapy Program, or GTP. Under this collaboration, GTP conducts discovery and preclinical activities enabling Investigational New Drug, or IND, applications and the Company conducts all clinical development, manufacturing, regulatory strategy, and commercialization activities under the agreement.

Through this collaboration, the Company has assembled a strong portfolio of genetic medicine product candidates, including two lead clinical product candidates: PBGM01 for the treatment of GM1 gangliosidosis, or GM1, and PBFT02 for the treatment of frontotemporal dementia, or FTD. The Company also has a collaboration agreement and a development services and clinical supply agreement with Catalent Maryland, Inc., or Catalent, for clinical scale manufacturing requirements.

v3.23.1
Risks and Liquidity
3 Months Ended
Mar. 31, 2023
Risks and Liquidity  
Risks and Liquidity

2. Risks and Liquidity

The Company has incurred recurring losses and negative cash flows from operations since inception and had an accumulated deficit of $526.7 million as of March 31, 2023. The Company anticipates incurring additional losses until such time, if ever, that it can generate significant sales of its product candidates currently in development. Substantial additional capital will be needed by the Company to fund its operations and to develop its product candidates.

The Company’s operations have consisted primarily of conducting preclinical studies, developing licensed technology, conducting clinical trials, and manufacturing clinical supply to support clinical trials. The Company faces risks associated with early-stage biotechnology companies whose product candidates are in development. Product candidates currently under development will require significant additional research and development efforts and establishing manufacturing capacity and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital for the Company to complete its research and development, achieve its research and development objectives, defend its intellectual property rights, and recruit and retain skilled personnel, and key members of management. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize revenue from product sales.

The Company plans to seek additional funding through public or private equity offerings, debt financings, other collaborations, strategic alliances and licensing arrangements. The Company may not be able to obtain financing on acceptable terms, or at all, and the Company may not be able to enter into strategic alliances or other arrangements on favorable terms, or at all. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. If the Company is unable to obtain funding or prospects of funding are unfavorable, the Company could be required to further delay, reduce or eliminate research and development programs, product portfolio expansion or future commercialization efforts, which could adversely affect its business prospects.

In accordance with Accounting Standards Update, or ASU, No. 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern, the Company has evaluated whether there are certain conditions and events, considered in the aggregate, 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. As of the issuance date of these financial statements, the Company expects that its cash, cash equivalents and marketable debt securities will be sufficient to fund its forecasted operating expenses and capital expenditure requirements for at least the next twelve months from the issuance date of these financial statements.

v3.23.1
Summary of Significant Accounting Policies
3 Months Ended
Mar. 31, 2023
Summary of Significant Accounting Policies  
Summary of Significant Accounting Policies

3. Summary of Significant Accounting Policies

The Company’s complete summary of significant accounting policies can be found in “Note 3. Summary of Significant Accounting Policies” in the audited financial statements included in the Company’s Annual Report filed on Form 10-K for the year ended December 31, 2022.

Basis of Presentation

The accompanying unaudited financial statements have been prepared in accordance with generally accepted accounting principles in the United States, or GAAP. Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification, or ASC, and Accounting Standards Updates promulgated by the Financial Accounting Standards Board, or FASB.

Interim Financial Statements

The accompanying unaudited interim financial statements have been prepared from the books and records of the Company in accordance with GAAP for interim financial information and Rule 10-01 of Regulation S-X promulgated by the United States Securities and Exchange Commission, or SEC, which permits reduced disclosures for interim periods. All adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the accompanying balance sheets, statements of operations and comprehensive loss, stockholders’ equity, and cash flows have been made. Although these interim financial statements do not include all of the information and footnotes required for complete annual financial statements, management believes the disclosures are adequate to make the information presented not misleading. Unaudited interim results of operations and cash flows are not necessarily indicative of the results that may be expected for the full year. Unaudited interim financial statements and footnotes should be read in conjunction with the audited financial statements and footnotes included in the Company’s 2022 Annual Report filed on Form 10-K.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and contingent liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates.

Estimates and assumptions are periodically reviewed and the effects of the revisions are reflected in the accompanying financial statements in the period they are determined to be necessary.

Fair Value of Financial Instruments

Management believes that the carrying amounts of the Company’s financial instruments, including cash equivalents, prepaid expenses, and accounts payable, approximate fair value due to the short-term nature of those instruments.

Concentration of credit risk

Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents, and marketable securities. The Company maintains a deposit account in a federally insured financial institution in excess of federally insured limits. The Company maintains a money market account in a federally insured financial institution in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash and cash equivalents beyond the normal credit risk associated with commercial banking relationships.

The Company maintains a portfolio of marketable debt securities, which is diversified to limit exposure related to counterparty risk, industry risk and security type risk. The Company maintains an investment policy which dictates the allocation of funds within our portfolio of marketable debt securities. The Company has not experienced any material losses in such portfolio.

Cash and cash equivalents

The Company considers all highly-liquid investments that have maturities of three months or less when acquired to be cash equivalents. Cash equivalents as of March 31, 2023 consisted of only money market funds. Cash consists of cash deposits at banking institutions.

Marketable securities

The Company classifies its marketable securities as available-for-sale, which include commercial paper, certificates of deposit, corporate debt securities, United States, or U.S., government debt securities and U.S. government agency securities with original maturities of greater than three months. These securities are carried at fair market value, with unrealized gains and losses reported in comprehensive loss and accumulated other comprehensive income (loss) within stockholders’ equity. Gains or losses on marketable securities sold are recognized as a component of other income, net in the statement of operations and comprehensive loss on the specific identification method. All marketable securities are available for use, as needed, to fund operations and therefore, the Company classifies all marketable securities as current assets within the balance sheet.

Property and Equipment, net

Property and equipment consists of laboratory equipment, office equipment, computer hardware and software, furniture and leasehold improvements and are recorded at cost. Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed as incurred. Property and equipment are depreciated on a straight-line basis over their estimated useful lives. The Company estimates useful life on an asset by asset basis, which generally consists of three years for computer hardware and software, five years for office equipment, five years for laboratory equipment and seven years for furniture and fixtures. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the asset.

The Company reviews long-lived assets, such as property and equipment, for impairment when events or changes in circumstances indicate the carrying amount of the assets may not be recoverable. If circumstances require a long-lived asset to be tested for possible impairment, recoverability is measured by comparison of the carrying amount of the assets to estimated future undiscounted cash flows that the assets are expected to generate. If the carrying amount of an asset exceeds its estimated future cash flows, then impairment expense is recognized for the amount by which the carrying amount of the asset exceeds the fair value of the asset. For the three months ended March 31, 2023 and 2022, no impairment expenses were recognized.

Leasing

The Company evaluates leases at their inception to determine if they are an operating lease or a finance lease. As of March 31, 2023, the Company has classified all leases with terms greater than one year, as operating leases.

The Company recognizes assets and liabilities for operating leases at their inception, based on the present value of all payments due under the lease agreement. The Company uses its incremental borrowing rate to determine the present value of operating leases, which is determined by referencing collateralized borrowing rates for debt instruments with terms similar to the respective lease. The Company utilizes the accounting policy election to not separate lease and non-lease components and the accounting policy election to not apply the recognition requirement to leases with a term of twelve months or less.

Share-based compensation

The Company measures share-based awards at grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the awards. The Company’s share-based compensation consists of restricted stock units, or RSUs, and options to purchase common stock, or stock option awards.

The Company uses the Black-Scholes option pricing model to value its stock option awards.

Estimating the fair value of stock option awards requires the input of assumptions, including, the expected term of stock options, and stock price volatility. The assumptions used in estimating the fair value of share-based awards represent management's estimate and involve inherent uncertainties and the application of management's judgment. As a result, if factors change and management uses different assumptions, share-based compensation expense could be materially different for future awards.

The expected term of the stock options is estimated using the "simplified method," as the Company has limited historical information from which to develop reasonable expectations about future exercise patterns and post-vesting employment termination behavior for its stock option grants. The simplified method is the midpoint between the vesting period and the contractual term of the option. For stock price volatility, the Company uses a composite of comparable public company data as a basis for its expected volatility to calculate the fair value of option grants. The selection of comparable public company data requires the application of management’s judgement.

The Company accounts for forfeitures of RSUs and stock option awards as they occur.

Research and Development

Research and development costs are expensed as incurred and consist primarily of expenses incurred with Penn, contract research organizations, contract manufacturing organizations, internal analytical and testing activities, and employee-related expenses, including salaries, benefits, and share-based compensation. Management makes estimates of the Company’s external accrued research and development expenses, which primarily relates to contract research organizations and contract manufacturing organizations, as of each balance sheet date in the Company’s financial statements based on an estimate of progress to completion of specific tasks using facts and circumstances known to the Company at that time. The Company determines the estimates by reviewing contracts, vendor agreements and change orders, and through discussions with our internal clinical personnel and external service providers as to the progress to completion of services and the agreed-upon fee to be paid for such services. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual and related expenses accordingly.

Net Loss Per Share

Basic net loss per share of common stock is computed by dividing net loss by the weighted average number of shares of common stock outstanding during each period. Diluted loss per share of common stock includes the effect, if any, from the potential exercise or conversion of securities, such as stock options, which would result in the issuance of incremental shares of common stock. For diluted net loss per share, the weighted average number of shares of common stock is the same for basic net loss per share due to the fact that when a net loss exists, dilutive securities are not included in the calculation as the impact is anti-dilutive.

The following potentially dilutive securities have been excluded from the computation of diluted weighted average shares of common stock outstanding, as they would be anti-dilutive:

Three Months Ended March 31, 

2023

    

2022

Stock options

13,609,572

 

10,650,128

Unvested restricted stock units

1,193,666

428,500

Employee stock purchase plan

131,436

197,655

14,934,674

 

11,276,283

Recently Adopted Accounting Pronouncements

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments, or ASU 2016-13, which replaces the incurred loss impairment methodology under current U.S. GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. ASU 2016-13 was subsequently updated by ASU No. 2019-04, Codification Improvements to Topic 326, Financial Instruments—Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments, to clarify that entities should include recoveries when estimating the allowance for credit losses. This guidance was effective for the Company starting in fiscal year 2023. The Company adopted ASU 2016-13 as of January 1, 2023, which did not have a material impact on its financial statements.

v3.23.1
Cash, Cash Equivalents and Marketable Securities
3 Months Ended
Mar. 31, 2023
Cash, Cash Equivalents and Marketable Securities  
Cash, Cash Equivalents and Marketable Securities

4. Cash, Cash Equivalents and Marketable Securities

The following table provides details regarding the Company’s portfolio of cash and cash equivalents:

Cost or

(in thousands)

    

Amortized cost

    

Unrealized gains

    

Unrealized losses

    

Fair value

March 31, 2023:

 

  

 

  

 

  

 

  

Cash accounts in banking institutions

$

8,070

$

-

$

-

$

8,070

Money market funds

25,302

-

-

25,302

Total

$

33,372

$

-

$

-

$

33,372

December 31, 2022:

 

  

 

  

 

  

 

  

Cash accounts in banking institutions

$

7,532

$

-

$

-

$

7,532

Money market funds

24,578

-

-

24,578

Commercial paper

2,491

-

-

2,491

Total

$

34,601

$

-

$

-

$

34,601

The following table provides details regarding the Company’s portfolio of marketable securities:

(in thousands)

    

Amortized cost

    

Unrealized gains

    

Unrealized losses

    

Fair value

March 31, 2023:

 

  

 

  

 

  

 

  

Certificates of deposit

$

22,756

$

6

$

(61)

$

22,701

Commercial paper

43,730

5

(41)

43,694

Corporate debt securities

43,959

-

(373)

43,586

U.S. government securities

16,849

36

(17)

16,868

U.S. government agency securities

7,535

18

-

7,553

Total

$

134,829

$

65

$

(492)

$

134,402

December 31, 2022:

 

  

 

  

 

  

 

  

Certificates of deposit

$

28,197

$

6

$

(92)

$

28,111

Commercial paper

58,572

12

(72)

58,512

Corporate debt securities

67,206

1

(786)

66,421

U.S. government securities

2,000

-

(35)

1,965

Total

$

155,975

$

19

$

(985)

$

155,009

The contractual maturities of our marketable securities as of March 31, 2023, are as follows:

(in thousands)

Amortized Cost

Fair Value

Due within one year

$

115,567

$

115,207

Due after one year through five years

19,262

19,195

Total

$

134,829

$

134,402

v3.23.1
Fair Value of Financial Instruments
3 Months Ended
Mar. 31, 2023
Fair Value of Financial Instruments  
Fair Value of Financial Instruments

5. Fair Value of Financial Instruments

Fair value is the price that could be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. Fair value determination in accordance with applicable accounting guidance requires that a number of significant judgments be made. Additionally, fair value is used on a nonrecurring basis to evaluate assets for impairment or as required for disclosure purposes by applicable accounting guidance on disclosures about fair value of financial instruments. Depending on the nature of the assets and liabilities, various valuation techniques and assumptions are used when estimating fair value. The carrying amounts of certain of the Company’s financial instruments, including prepaid expense and accounts payable are shown at cost, which approximates fair value due to the short-term nature of these instruments. The Company follows the provisions of FASB ASC Topic 820, Fair Value Measurement, for financial assets and liabilities measured on a recurring basis. The guidance requires fair value measurements be classified and disclosed in one of the following three categories:

Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities.
Level 2: Quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liabilities.
Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).

The following fair value hierarchy table presents information about the Company’s assets measured at fair value on a recurring basis. Included within cash and cash equivalents on the balance sheet, but excluded from the fair value hierarchy table, are cash deposits held at financial institutions:

Fair value measurement at

reporting date using

Quoted prices

 

in active

 

Significant

 

 

markets for

 

other

 

Significant

 

identical

 

observable

 

unobservable

 

assets

 

inputs

inputs

(in thousands)

    

(Level 1)

    

(Level 2)

    

(Level 3)

March 31, 2023:

 

  

 

  

 

  

Assets

 

  

 

  

 

  

Cash equivalents:

Money market funds

$

25,302

$

-

$

-

Total cash equivalents

25,302

-

-

Marketable securities:

Certificates of deposit

-

22,701

-

Commercial paper

-

43,694

-

Corporate debt securities

-

43,586

-

U.S. government securities

-

16,868

-

U.S. government agency securities

-

7,553

-

Total marketable securities

-

134,402

-

Total financial assets

$

25,302

$

134,402

$

-

December 31, 2022:

Assets

 

  

 

  

 

  

Cash equivalents:

Money market funds

$

24,578

$

-

$

-

Commercial paper

-

2,491

-

Total cash equivalents

24,578

2,491

-

Marketable securities:

Certificates of deposit

-

28,111

-

Commercial paper

-

58,512

-

Corporate debt securities

-

66,421

-

U.S. government securities

-

1,965

-

Total marketable securities

-

155,009

-

Total financial assets

$

24,578

$

157,500

$

-

v3.23.1
Property and Equipment, net
3 Months Ended
Mar. 31, 2023
Property and Equipment, net  
Property and Equipment, net

6. Property and Equipment, net

Property and Equipment, net, consist of the following:

(in thousands)

March 31, 2023

December 31, 2022

Laboratory equipment

$

10,379

$

9,972

Office equipment

601

601

Computer hardware and software

1,128

1,090

Furniture and fixtures

1,208

1,208

Leasehold improvements

13,506

13,506

Construction in progress

908

1,291

Total property and equipment

27,730

27,668

Accumulated depreciation and amortization

(6,131)

(5,153)

$

21,599

$

22,515

Depreciation expense was $1.0 million and $0.9 million for the three months ended March 31, 2023 and 2022, respectively.

v3.23.1
Accrued Expenses and Other Current Liabilities
3 Months Ended
Mar. 31, 2023
Accrued Expenses and Other Current Liabilities  
Accrued Expenses and Other Current Liabilities

7. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following:

(in thousands)

    

March 31, 2023

    

December 31, 2022

Professional fees

$

874

$

602

Compensation and related benefits

 

3,370

 

8,446

Research and development

 

2,634

 

1,878

Property and equipment

29

85

Amount due to Catalent in connection with Letter Agreements

 

4,000

 

$

10,907

$

11,011

v3.23.1
Leases
3 Months Ended
Mar. 31, 2023
Leases  
Leases

8. Leases

The Company is party to a lease agreement for office space, or the Lease Agreement, in Philadelphia, Pennsylvania. The Lease Agreement commenced in February 2021 and is expected to expire in December 2031. The Company has an option to extend the term of the Lease Agreement by up to two five-year terms. This option to extend was not recognized as part of the Company's measurement of the right of use, or ROU, asset and operating lease liability as of March 31, 2023. The landlord provided the Company with a tenant improvement allowance of $2.8 million, for which the related expenditures were paid directly by the landlord.

The Company is also party to a lease agreement for laboratory space, or the Laboratory Lease Agreement, in Hopewell, New Jersey. The laboratory is focused on state-of-the-art analytical capabilities, assay development and validation, and clinical product testing to support both viral vector manufacturing and clinical development. The Laboratory Lease Agreement commenced in March 2021 and is expected to expire in February 2036. The Company has an option to extend the term of the Laboratory Lease Agreement by up to two five-year terms. This option to extend was not recognized as part of the Company's measurement of the ROU asset and operating lease liability as of March 31, 2023. The landlord provided the Company with a tenant improvement allowance of $1.3 million in connection with the Laboratory Lease Agreement, for which the related expenditures were paid by the Company and will be reimbursed by the landlord. As of March 31, 2023, $0.1 million of reimbursements were unpaid by the landlord and recorded within other current assets.

The following table summarizes future minimum lease payments under the Company’s operating leases:

(in thousands)

    

    

2023

$

2,603

2024

 

3,553

2025

 

3,654

2026

 

3,757

2027

 

3,864

Thereafter

 

29,679

Total undiscounted lease payments

47,110

Less: imputed interest

(20,158)

Total lease liabilities

$

26,952

Operating lease expense was $0.8 million and $0.8 million for the three months ended March 31, 2023 and 2022, respectively.

v3.23.1
Commitments and Contingencies
3 Months Ended
Mar. 31, 2023
Commitments and Contingencies.  
Commitments and Contingencies

9. Commitments and Contingencies

Amended and Restated Research, Collaboration and License Arrangement with Penn

The Company has a research, collaboration and licensing agreement with Penn, as amended, or the Penn Agreement, for research and development collaborations and exclusive license rights to patents for certain products and technologies. Under the Penn Agreement, the Company has obligations to fund certain research relating to the preclinical development of selected products in research programs as well as exploratory research programs in non-rare and/or non-monogenic, or large CNS indications, currently TLE. In addition, the Company will fund discovery research conducted by Penn through August 3, 2026 and will receive exclusive rights, subject to certain limitations, to technologies resulting from the discovery research for the Company’s products developed with GTP, such as novel capsids, toxicity reduction technologies and delivery and formulation improvements. This funding commitment for the discovery research is $5.0 million annually, paid in quarterly increments of $1.3 million through June, 2026.

The Penn Agreement includes an exploratory research program focused on discovering targets and novel gene therapy candidates for large CNS indications, currently focused on TLE, and can be expanded to other large CNS diseases upon mutual agreement. The initial term of the exploratory research program is until August 2024, which term can be extended by mutual agreement. Under the exploratory research program, the Company will have the right to further develop and commercialize any gene therapy product candidates specific for those selected targets (and any future large CNS diseases that are mutually agreed upon) that may arise from the exploratory research programs on substantially the same terms of the current Penn Agreement.

Under the Penn Agreement, the Company has eight remaining options available to commence additional licensed programs for CNS indications and has until August 3, 2026, to exercise these options. If the Company were to exercise any of these options, it would owe Penn a non-refundable upfront fee of $1.0 million per product indication, with $0.5 million due upfront and another $0.5 million fee owed upon a further developmental milestone. The Company has the obligation to fund certain research relating to the preclinical development of each licensed program.

The Penn Agreement requires that the Company make payments of up to (i) $16.5 million per product candidate for rare, monogenic disorders in the aggregate and (ii) $39.0 million per product candidate in the aggregate arising from the exploratory program for large CNS indications, currently for TLE. Each payment will be due upon the achievement of specific development milestone events by such licensed product for a first indication, reduced development milestone payments for the second and third indications and no development milestone payments for subsequent indications. In

addition, on a product-by-product basis, the Company is obligated to make up to $55.0 million in sales milestone payments on each licensed product based on annual sales of the licensed product in excess of defined thresholds.

Upon successful commercialization of a product using the licensed technology, the Company is obligated to pay to Penn, on a licensed product-by-licensed product and country-by-country basis, tiered royalties (subject to customary reductions) in the mid-single digits on annual worldwide net sales of such licensed product. In addition, the Company is obligated to pay to Penn a percentage of sublicensing income, ranging from the mid-single digits to low double digits, for sublicenses under the Penn Agreement. The agreement will expire on a licensed product-by-licensed product and country-by-country basis upon the later of (i) the expiration of the last valid claim of the licensed patent rights that covers the exploitation of such licensed product in such country, and (ii) the expiration of the royalty period. In addition, the Company will pay a tiered transaction fee of 1-2% of the net proceeds upon certain change of control events.

During the three months ended March 31, 2023, the Company did not make any payments for acquired in-process research and development. During the three months ended March 31, 2022, the Company made payments under the Penn Agreement for acquired in-process research and development of $1.5 million related to the achievement of a development milestone.

Catalent Agreements

In June 2019, the Company entered into a collaboration agreement, or the Collaboration Agreement, with Catalent. As part of the Collaboration Agreement, the Company was required to pay an annual fee for five years ending in 2025 for the exclusive use of a dedicated clean room suite, or the Clean Room Suite.

In April 2020, the Company entered into a development services and clinical supply agreement, or the Manufacturing and Supply Agreement, with Catalent to secure clinical scale manufacturing capacity for batches of active pharmaceutical ingredients for the Company’s gene therapy product candidates. The Manufacturing and Supply Agreement confirms the terms contemplated by the Collaboration Agreement and the Collaboration Agreement continues to be in effect pursuant to its terms. Under the terms of the Manufacturing and Supply Agreement, Catalent agreed to manufacture batches of drug product for the Company’s gene therapy product candidates at the Clean Room Suite at a Catalent facility provided for in the Collaboration Agreement. The Manufacturing and Supply Agreement provided for a term of five years. The Manufacturing and Supply Agreement also included minimum annual purchase commitments. The Company has the right to terminate the Manufacturing and Supply Agreement for convenience or other reasons specified in the Manufacturing and Supply Agreement upon prior written notice. If the Company terminates the Manufacturing and Supply Agreement, it will be obligated to pay an early termination fee to Catalent.

Under both the Collaboration Agreement and the Manufacturing and Supply Agreement, the Company had an annual minimum commitment of $10.6 million per year owed to Catalent for five years from the validation of the Clean Room, subject to certain inflationary adjustments.

On March 31, 2023, the Company entered into certain letter agreements amending each of (i) the Collaboration Agreement and (ii) the Manufacturing and Supply Agreement, together with the Collaboration Agreement, the Existing Agreements.

Letter agreement I, or Agreement I, eliminated the minimum annual purchase obligation and the obligation to pay an annual fee for use of the Clean Room Suite, thereby eliminating the annual minimum commitment of $10.6 million per year owed to Catalent through November 2025 under the Existing Agreements. In consideration of Agreement I, the Company will make aggregate payments to Catalent of $6.0 million between June 30, 2023 and May 1, 2024. The Company accrued the $6.0 million of aggregate payments as of the three-months ended March 31, 2023.

Letter agreement II, or Agreement II, and together with Agreement I, the Letter Agreements, extended the term of the Existing Agreements until November 6, 2030, and established a limited exclusive relationship between the Company and

Catalent for the manufacture of bulk drug substance and drug product for the Company’s adeno-associated virus delivery therapeutic product candidates for the treatment of FTD and GM1. The limited exclusive relationship under Agreement II would convert to a non-exclusive relationship (i) in the event Catalent fails to meet certain performance standards and (ii) following certain conditional events related to the divestiture by the Company of either FTD or GM1, in which case, if such events occur, the Company would pay Catalent certain fees. In addition, in the event of certain transactions, the Company may terminate the Existing Agreements for convenience with respect to such products, in which case, the Company would pay to Catalent a certain termination fee.

Immediately prior to the execution of the Letter Agreements, the Company had a $5.3 million prepaid asset related to upfront payments made to secure the Clean Room Suite. In connection with the Letter Agreements, the Company no longer has exclusive access to the Clean Room Suite at Catalent and, as a result, the Company recognized an expense of $5.3 million related to the elimination of the prepaid asset as of the three months ended March 31, 2023.

The Company classified the $11.3 million of expenses, which comprises of $6.0 million in aggregate payments due to Catalent and the $5.3 million elimination of the prepaid asset, as general and administrative expense within the statement of operations for the three months ended March 31, 2023, as both amounts do not directly relate to the future advancement of our research and development programs.

Employment Agreements

The Company has entered into employment agreements with key personnel providing for compensation and, in certain circumstances, severance and acceleration of vesting in stock-based compensation awards, as described in the respective employment agreements.

v3.23.1
Share-Based Compensation
3 Months Ended
Mar. 31, 2023
Share-Based Compensation  
Share-Based Compensation

10. Share-Based Compensation

Equity Incentive Plan

The Company has three equity incentive plans: the 2018 Equity Incentive Plan, as amended, or the 2018 Plan, the 2020 Equity Incentive Plan, or the Incentive Plan, and the 2021 Equity Inducement Plan, as amended, or the Inducement Plan. New awards can only be granted under the Incentive Plan and the Inducement Plan.

The total number of shares authorized under the Incentive Plan as of March 31, 2023 was 13,101,661. Additionally, any awards previously issued under our 2018 Plan which are forfeited become available for issuance under the Incentive Plan. As of March 31, 2023, 4,439,463 shares were available for future grants under the Incentive Plan. The number of shares of the Company’s common stock that may be issued pursuant to rights granted under the Incentive Plan shall automatically increase on January 1st of each year, commencing on January 1, 2021 and continuing for ten years, in an amount equal to five percent of the total number of shares of the Company’s common stock outstanding on December 31st of the preceding calendar year, subject to the discretion of the board of directors or compensation committee to determine a lesser number of shares shall be added for such year. As a result, the number of shares reserved for issuance under the Incentive Plan increased by 2,730,735 and 2,712,249 shares in January 2023 and 2022, respectively.

The Incentive Plan provides for the granting of common stock, incentive stock options, nonqualified stock options, restricted stock awards, and/or stock appreciation rights to employees, directors, and other persons, as determined by the Company’s board of directors. The Company’s stock options awarded to date under the Incentive Plan vest based on a requisite service period, generally over four-year periods, and have a term of ten years.

The Inducement Plan was approved by the Company’s board of directors in July 2021 and subsequently amended in February 2022 and February 2023. The total number of shares authorized under the Inducement Plan as of March 31, 2023 was 2,500,000. Of this amount, 880,967 shares were available for future grants as of March 31, 2023. The Inducement Plan provides for the granting of nonqualified stock options and restricted stock awards to employees hired

by the Company, as determined by the Company’s board of directors. The Company’s stock options awarded to date under the Inducement Plan vest based on requisite service period and have a term of ten years. The Company’s restricted stock units awarded to date under the Inducement Plan vest based on requisite service period and have a term based on each award agreement.

The Company measures share-based awards at their grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the awards. The Company recorded share-based compensation expense in the following expense categories in its accompanying statements of operations for the period presented:

Three Months Ended March 31, 

(in thousands)

2023

    

2022

Research and development

$

1,628

$

2,996

General and administrative

 

1,156

 

3,341

$

2,784

$

6,337

During the three months ended March 31, 2023 and 2022, there was no expense related to the modifications of awards.

The following table summarizes stock option activity for the three months ended March 31, 2023:

    

    

    

Weighted

Weighted

average

average

remaining

Number of

exercise price

contractual

shares

per share

term (years)

Outstanding at January 1, 2023

 

11,411,390

 

$

9.01

 

7.1

Granted

 

2,950,915

1.08

 

  

Exercised

 

 

  

Forfeited

 

(752,733)

13.69

 

  

Outstanding at March 31, 2023

 

13,609,572

$

7.02

 

7.4

Vested and exercisable at March 31, 2023

 

6,011,809

$

10.96

 

5.1

Vested or expected to vest at March 31, 2023

 

13,609,572

$

7.02

 

7.4

The weighted average grant date fair value of options granted was $0.83 and $3.45 for the three months ended March 31, 2023 and 2022, respectively. As of March 31, 2023, the total unrecognized compensation expense related to unvested stock option awards was $21.9 million, which the Company expects to recognize over a weighted average period of 2.2 years.

The 2018 Plan and the Incentive Plan provide certain holders of stock options an election to early exercise prior to vesting. The Company has the right to repurchase early exercised options without transferring any appreciation in the value of the underlying shares to the employee if the employee terminates employment before the end of the original vesting period. The repurchase price is the lesser of the original exercise price or the then fair value of the Company’s common stock. As of March 31, 2023, 70,456 options to purchase common stock are unvested, but exercisable, under early exercise provisions.

The fair value of each option was estimated on the date of grant using the weighted average assumptions in the table below:

Three Months Ended March 31, 

2023

2022

Expected volatility

92.4

%  

95.4

%

Risk‑free interest rate

3.5

%

1.5

%

Expected term

6.0

years

6.0

years

Expected dividend yield

Restricted Stock Units

The Company issues restricted stock units, or RSUs, to employees that vest over periods as determined by the board of directors. Any unvested shares are forfeited upon termination of services. The fair value of the RSUs is equal to the fair market value price of the Company’s common stock on the date of grant. Compensation expense is recognized on a straight-line basis over the vesting period of the RSUs.

The following table summarizes activity related to RSU awards during the three months ended March 31, 2023:

    

    

Weighted average

 

Number of shares

 

grant date fair value

Unvested balance at January 1, 2022

 

1,229,166

 

$

2.98

Granted

 

 

$

Vested

(12,000)

21.85

Forfeited

 

(23,500)

 

$

2.40

Unvested balance at March 31, 2023

 

1,193,666

 

$

2.85

As of March 31, 2023, the total unrecognized expense related to all RSUs was $2.4 million, which the Company expects to recognize over a weighted average period of 1.5 years.

Employee Stock Purchase Plan

The Company’s 2020 Employee Stock Purchase Plan, or the ESPP, became effective on February 28, 2020. The ESPP authorizes the issuance of up to 1,981,766 shares of the Company’s common stock. Of this amount, 1,666,061 were available for future grants as of March 31, 2023. The number of shares of the Company’s common stock that may be issued pursuant to rights granted under the ESPP shall automatically increase on January 1st of each year and continuing for ten years, in an amount equal to one percent of the total number of shares of the Company’s common stock outstanding on December 31st of the preceding calendar year, subject to the discretion of the board of directors or compensation committee to determine a lesser number of shares shall be added for such year. As a result, on January 1, 2023, the number of shares reserved for issuance under the ESPP increased by 546,147 shares, resulting in a total of 1,981,766 shares authorized for issuance.

Under the ESPP, eligible employees can purchase the Company’s common stock through accumulated payroll deductions at such times as are established by the compensation committee. Eligible employees may purchase the Company’s common stock at 85% of the lower of the fair market value of the Company’s common stock on the first day of the offering period or on the last day of the offering period. The offering periods under the ESPP have a duration of six months, with periods ending in May and November of each calendar year. Eligible employees may contribute up to 15% of their eligible compensation. Under the ESPP, a participant may not accrue rights to purchase more than $25,000 worth of the Company’s common stock for each calendar year in which such right is outstanding or purchase more than 4,000 shares of the Company’s common stock in any single offering period.

In accordance with the guidance in ASC 718-50, Compensation – Stock Compensation, the ability to purchase shares of the Company’s common stock at 85% of the lower of the price on the first day of the offering period or the last day of the offering period (i.e. the purchase date) represents an option and, therefore, the ESPP is a compensatory plan under this guidance. Accordingly, share-based compensation expense is determined based on the option’s grant-date fair value as estimated by applying the Black Scholes option-pricing model and is recognized over the withholding period. The Company recognized share-based compensation expense of de minimus and $0.1 million during the three months ended March 31, 2023 and 2022, respectively, related to the ESPP.

v3.23.1
Subsequent Events
3 Months Ended
Mar. 31, 2023
Subsequent Events.  
Subsequent Events

11. Subsequent Events

None.

v3.23.1
Summary of Significant Accounting Policies (Policies)
3 Months Ended
Mar. 31, 2023
Summary of Significant Accounting Policies  
Basis of Presentation

Basis of Presentation

The accompanying unaudited financial statements have been prepared in accordance with generally accepted accounting principles in the United States, or GAAP. Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification, or ASC, and Accounting Standards Updates promulgated by the Financial Accounting Standards Board, or FASB.

Interim Financial Statements

Interim Financial Statements

The accompanying unaudited interim financial statements have been prepared from the books and records of the Company in accordance with GAAP for interim financial information and Rule 10-01 of Regulation S-X promulgated by the United States Securities and Exchange Commission, or SEC, which permits reduced disclosures for interim periods. All adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the accompanying balance sheets, statements of operations and comprehensive loss, stockholders’ equity, and cash flows have been made. Although these interim financial statements do not include all of the information and footnotes required for complete annual financial statements, management believes the disclosures are adequate to make the information presented not misleading. Unaudited interim results of operations and cash flows are not necessarily indicative of the results that may be expected for the full year. Unaudited interim financial statements and footnotes should be read in conjunction with the audited financial statements and footnotes included in the Company’s 2022 Annual Report filed on Form 10-K.

Use of Estimates

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and contingent liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates.

Estimates and assumptions are periodically reviewed and the effects of the revisions are reflected in the accompanying financial statements in the period they are determined to be necessary.

Fair Value of Financial Instruments

Fair Value of Financial Instruments

Management believes that the carrying amounts of the Company’s financial instruments, including cash equivalents, prepaid expenses, and accounts payable, approximate fair value due to the short-term nature of those instruments.

Concentration of credit risk

Concentration of credit risk

Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents, and marketable securities. The Company maintains a deposit account in a federally insured financial institution in excess of federally insured limits. The Company maintains a money market account in a federally insured financial institution in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash and cash equivalents beyond the normal credit risk associated with commercial banking relationships.

The Company maintains a portfolio of marketable debt securities, which is diversified to limit exposure related to counterparty risk, industry risk and security type risk. The Company maintains an investment policy which dictates the allocation of funds within our portfolio of marketable debt securities. The Company has not experienced any material losses in such portfolio.

Cash and cash equivalents

Cash and cash equivalents

The Company considers all highly-liquid investments that have maturities of three months or less when acquired to be cash equivalents. Cash equivalents as of March 31, 2023 consisted of only money market funds. Cash consists of cash deposits at banking institutions.

Marketable securities

Marketable securities

The Company classifies its marketable securities as available-for-sale, which include commercial paper, certificates of deposit, corporate debt securities, United States, or U.S., government debt securities and U.S. government agency securities with original maturities of greater than three months. These securities are carried at fair market value, with unrealized gains and losses reported in comprehensive loss and accumulated other comprehensive income (loss) within stockholders’ equity. Gains or losses on marketable securities sold are recognized as a component of other income, net in the statement of operations and comprehensive loss on the specific identification method. All marketable securities are available for use, as needed, to fund operations and therefore, the Company classifies all marketable securities as current assets within the balance sheet.

Property and Equipment, net

Property and Equipment, net

Property and equipment consists of laboratory equipment, office equipment, computer hardware and software, furniture and leasehold improvements and are recorded at cost. Maintenance and repairs that do not improve or extend the lives of the respective assets are expensed as incurred. Property and equipment are depreciated on a straight-line basis over their estimated useful lives. The Company estimates useful life on an asset by asset basis, which generally consists of three years for computer hardware and software, five years for office equipment, five years for laboratory equipment and seven years for furniture and fixtures. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the asset.

The Company reviews long-lived assets, such as property and equipment, for impairment when events or changes in circumstances indicate the carrying amount of the assets may not be recoverable. If circumstances require a long-lived asset to be tested for possible impairment, recoverability is measured by comparison of the carrying amount of the assets to estimated future undiscounted cash flows that the assets are expected to generate. If the carrying amount of an asset exceeds its estimated future cash flows, then impairment expense is recognized for the amount by which the carrying amount of the asset exceeds the fair value of the asset. For the three months ended March 31, 2023 and 2022, no impairment expenses were recognized.

Leasing

Leasing

The Company evaluates leases at their inception to determine if they are an operating lease or a finance lease. As of March 31, 2023, the Company has classified all leases with terms greater than one year, as operating leases.

The Company recognizes assets and liabilities for operating leases at their inception, based on the present value of all payments due under the lease agreement. The Company uses its incremental borrowing rate to determine the present value of operating leases, which is determined by referencing collateralized borrowing rates for debt instruments with terms similar to the respective lease. The Company utilizes the accounting policy election to not separate lease and non-lease components and the accounting policy election to not apply the recognition requirement to leases with a term of twelve months or less.

Share-based compensation

Share-based compensation

The Company measures share-based awards at grant-date fair value and records compensation expense on a straight-line basis over the vesting period of the awards. The Company’s share-based compensation consists of restricted stock units, or RSUs, and options to purchase common stock, or stock option awards.

The Company uses the Black-Scholes option pricing model to value its stock option awards.

Estimating the fair value of stock option awards requires the input of assumptions, including, the expected term of stock options, and stock price volatility. The assumptions used in estimating the fair value of share-based awards represent management's estimate and involve inherent uncertainties and the application of management's judgment. As a result, if factors change and management uses different assumptions, share-based compensation expense could be materially different for future awards.

The expected term of the stock options is estimated using the "simplified method," as the Company has limited historical information from which to develop reasonable expectations about future exercise patterns and post-vesting employment termination behavior for its stock option grants. The simplified method is the midpoint between the vesting period and the contractual term of the option. For stock price volatility, the Company uses a composite of comparable public company data as a basis for its expected volatility to calculate the fair value of option grants. The selection of comparable public company data requires the application of management’s judgement.

The Company accounts for forfeitures of RSUs and stock option awards as they occur.

Research and Development

Research and Development

Research and development costs are expensed as incurred and consist primarily of expenses incurred with Penn, contract research organizations, contract manufacturing organizations, internal analytical and testing activities, and employee-related expenses, including salaries, benefits, and share-based compensation. Management makes estimates of the Company’s external accrued research and development expenses, which primarily relates to contract research organizations and contract manufacturing organizations, as of each balance sheet date in the Company’s financial statements based on an estimate of progress to completion of specific tasks using facts and circumstances known to the Company at that time. The Company determines the estimates by reviewing contracts, vendor agreements and change orders, and through discussions with our internal clinical personnel and external service providers as to the progress to completion of services and the agreed-upon fee to be paid for such services. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual and related expenses accordingly.

Net Loss Per Share

Net Loss Per Share

Basic net loss per share of common stock is computed by dividing net loss by the weighted average number of shares of common stock outstanding during each period. Diluted loss per share of common stock includes the effect, if any, from the potential exercise or conversion of securities, such as stock options, which would result in the issuance of incremental shares of common stock. For diluted net loss per share, the weighted average number of shares of common stock is the same for basic net loss per share due to the fact that when a net loss exists, dilutive securities are not included in the calculation as the impact is anti-dilutive.

The following potentially dilutive securities have been excluded from the computation of diluted weighted average shares of common stock outstanding, as they would be anti-dilutive:

Three Months Ended March 31, 

2023

    

2022

Stock options

13,609,572

 

10,650,128

Unvested restricted stock units

1,193,666

428,500

Employee stock purchase plan

131,436

197,655

14,934,674

 

11,276,283

Recently Adopted Accounting Pronouncements

Recently Adopted Accounting Pronouncements

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments, or ASU 2016-13, which replaces the incurred loss impairment methodology under current U.S. GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. ASU 2016-13 was subsequently updated by ASU No. 2019-04, Codification Improvements to Topic 326, Financial Instruments—Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments, to clarify that entities should include recoveries when estimating the allowance for credit losses. This guidance was effective for the Company starting in fiscal year 2023. The Company adopted ASU 2016-13 as of January 1, 2023, which did not have a material impact on its financial statements.

v3.23.1
Summary of Significant Accounting Policies (Tables)
3 Months Ended
Mar. 31, 2023
Summary of Significant Accounting Policies  
Schedule of antidilutive securities excluded from computation of earnings per share

Three Months Ended March 31, 

2023

    

2022

Stock options

13,609,572

 

10,650,128

Unvested restricted stock units

1,193,666

428,500

Employee stock purchase plan

131,436

197,655

14,934,674

 

11,276,283

v3.23.1
Cash, Cash Equivalents and Marketable Securities (Tables)
3 Months Ended
Mar. 31, 2023
Cash, Cash Equivalents and Marketable Securities  
Schedule of details regarding the Company's portfolio of cash and cash equivalents

Cost or

(in thousands)

    

Amortized cost

    

Unrealized gains

    

Unrealized losses

    

Fair value

March 31, 2023:

 

  

 

  

 

  

 

  

Cash accounts in banking institutions

$

8,070

$

-

$

-

$

8,070

Money market funds

25,302

-

-

25,302

Total

$

33,372

$

-

$

-

$

33,372

December 31, 2022:

 

  

 

  

 

  

 

  

Cash accounts in banking institutions

$

7,532

$

-

$

-

$

7,532

Money market funds

24,578

-

-

24,578

Commercial paper

2,491

-

-

2,491

Total

$

34,601

$

-

$

-

$

34,601

Schedule of details regarding the Company's portfolio of marketable securities

(in thousands)

    

Amortized cost

    

Unrealized gains

    

Unrealized losses

    

Fair value

March 31, 2023:

 

  

 

  

 

  

 

  

Certificates of deposit

$

22,756

$

6

$

(61)

$

22,701

Commercial paper

43,730

5

(41)

43,694

Corporate debt securities

43,959

-

(373)

43,586

U.S. government securities

16,849

36

(17)

16,868

U.S. government agency securities

7,535

18

-

7,553

Total

$

134,829

$

65

$

(492)

$

134,402

December 31, 2022:

 

  

 

  

 

  

 

  

Certificates of deposit

$

28,197

$

6

$

(92)

$

28,111

Commercial paper

58,572

12

(72)

58,512

Corporate debt securities

67,206

1

(786)

66,421

U.S. government securities

2,000

-

(35)

1,965

Total

$

155,975

$

19

$

(985)

$

155,009

Contractual Final Maturities of Marketable Securities

(in thousands)

Amortized Cost

Fair Value

Due within one year

$

115,567

$

115,207

Due after one year through five years

19,262

19,195

Total

$

134,829

$

134,402

v3.23.1
Fair Value of Financial Instruments (Tables)
3 Months Ended
Mar. 31, 2023
Fair Value of Financial Instruments  
Summary of assets measured at fair value on a recurring basis

Fair value measurement at

reporting date using

Quoted prices

 

in active

 

Significant

 

 

markets for

 

other

 

Significant

 

identical

 

observable

 

unobservable

 

assets

 

inputs

inputs

(in thousands)

    

(Level 1)

    

(Level 2)

    

(Level 3)

March 31, 2023:

 

  

 

  

 

  

Assets

 

  

 

  

 

  

Cash equivalents:

Money market funds

$

25,302

$

-

$

-

Total cash equivalents

25,302

-

-

Marketable securities:

Certificates of deposit

-

22,701

-

Commercial paper

-

43,694

-

Corporate debt securities

-

43,586

-

U.S. government securities

-

16,868

-

U.S. government agency securities

-

7,553

-

Total marketable securities

-

134,402

-

Total financial assets

$

25,302

$

134,402

$

-

December 31, 2022:

Assets

 

  

 

  

 

  

Cash equivalents:

Money market funds

$

24,578

$

-

$

-

Commercial paper

-

2,491

-

Total cash equivalents

24,578

2,491

-

Marketable securities:

Certificates of deposit

-

28,111

-

Commercial paper

-

58,512

-

Corporate debt securities

-

66,421

-

U.S. government securities

-

1,965

-

Total marketable securities

-

155,009

-

Total financial assets

$

24,578

$

157,500

$

-

v3.23.1
Property and Equipment, net (Tables)
3 Months Ended
Mar. 31, 2023
Property and Equipment, net  
Schedule of property and equipment, net

(in thousands)

March 31, 2023

December 31, 2022

Laboratory equipment

$

10,379

$

9,972

Office equipment

601

601

Computer hardware and software

1,128

1,090

Furniture and fixtures

1,208

1,208

Leasehold improvements

13,506

13,506

Construction in progress

908

1,291

Total property and equipment

27,730

27,668

Accumulated depreciation and amortization

(6,131)

(5,153)

$

21,599

$

22,515

v3.23.1
Accrued Expenses and Other Current Liabilities (Tables)
3 Months Ended
Mar. 31, 2023
Accrued Expenses and Other Current Liabilities  
Schedule of accrued liabilities and other current liabilities

(in thousands)

    

March 31, 2023

    

December 31, 2022

Professional fees

$

874

$

602

Compensation and related benefits

 

3,370

 

8,446

Research and development

 

2,634

 

1,878

Property and equipment

29

85

Amount due to Catalent in connection with Letter Agreements

 

4,000

 

$

10,907

$

11,011

v3.23.1
Leases (Tables)
3 Months Ended
Mar. 31, 2023
Leases  
Schedule of future minimum rental payments for operating leases

(in thousands)

    

    

2023

$

2,603

2024

 

3,553

2025

 

3,654

2026

 

3,757

2027

 

3,864

Thereafter

 

29,679

Total undiscounted lease payments

47,110

Less: imputed interest

(20,158)

Total lease liabilities

$

26,952

v3.23.1
Share-Based Compensation (Tables)
3 Months Ended
Mar. 31, 2023
Share-Based Compensation  
Schedule of share-based compensation expense category

Three Months Ended March 31, 

(in thousands)

2023

    

2022

Research and development

$

1,628

$

2,996

General and administrative

 

1,156

 

3,341

$

2,784

$

6,337

Summary of stock option activity plan

    

    

    

Weighted

Weighted

average

average

remaining

Number of

exercise price

contractual

shares

per share

term (years)

Outstanding at January 1, 2023

 

11,411,390

 

$

9.01

 

7.1

Granted

 

2,950,915

1.08

 

  

Exercised

 

 

  

Forfeited

 

(752,733)

13.69

 

  

Outstanding at March 31, 2023

 

13,609,572

$

7.02

 

7.4

Vested and exercisable at March 31, 2023

 

6,011,809

$

10.96

 

5.1

Vested or expected to vest at March 31, 2023

 

13,609,572

$

7.02

 

7.4

Schedule of weighted average assumptions applied to options

Three Months Ended March 31, 

2023

2022

Expected volatility

92.4

%  

95.4

%

Risk‑free interest rate

3.5

%

1.5

%

Expected term

6.0

years

6.0

years

Expected dividend yield

Summary of activity related to restricted stock unit

    

    

Weighted average

 

Number of shares

 

grant date fair value

Unvested balance at January 1, 2022

 

1,229,166

 

$

2.98

Granted

 

 

$

Vested

(12,000)

21.85

Forfeited

 

(23,500)

 

$

2.40

Unvested balance at March 31, 2023

 

1,193,666

 

$

2.85

v3.23.1
Nature of Operations (Details)
3 Months Ended
Mar. 31, 2023
item
Nature of Operations  
Number of lead clinical product candidates 2
v3.23.1
Risks and Liquidity (Details) - USD ($)
$ in Thousands
Mar. 31, 2023
Dec. 31, 2022
Risks and Liquidity    
Accumulated deficit $ (526,744) $ (492,406)
v3.23.1
Summary of Significant Accounting Policies (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Asset impairment charges $ 0 $ 0
Amount of antidilutive securities excluded from computation of earnings per share 14,934,674 11,276,283
Operating lease liability $ 26,952  
Stock options (including shares subject to repurchase)    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Amount of antidilutive securities excluded from computation of earnings per share 13,609,572 10,650,128
Unvested restricted stock units    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Amount of antidilutive securities excluded from computation of earnings per share 1,193,666 428,500
Employee stock purchase plan    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Amount of antidilutive securities excluded from computation of earnings per share 131,436 197,655
Computer hardware and software    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Useful life 3 years  
Office equipment    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Useful life 5 years  
Laboratory equipment    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Useful life 5 years  
Furniture and fixtures    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Useful life 7 years  
v3.23.1
Cash, cash equivalents and marketable securities - Portfolio of Cash and Cash Equivalents (Details) - USD ($)
$ in Thousands
Mar. 31, 2023
Dec. 31, 2022
Cash and cash equivalents    
Cost or Amortized cost $ 33,372 $ 34,601
Fair value 33,372 34,601
Cash accounts in banking institutions    
Cash and cash equivalents    
Cost or Amortized cost 8,070 7,532
Fair value 8,070 7,532
Money market funds    
Cash and cash equivalents    
Cost or Amortized cost 25,302 24,578
Fair value $ 25,302 24,578
Commercial paper    
Cash and cash equivalents    
Cost or Amortized cost   2,491
Fair value   $ 2,491
v3.23.1
Cash, cash equivalents and marketable securities - Portfolio of Marketable Securities (Details) - USD ($)
$ in Thousands
Mar. 31, 2023
Dec. 31, 2022
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]    
Amortized cost $ 134,829 $ 155,975
Unrealized gains 65 19
Unrealized losses (492) (985)
Fair value 134,402 155,009
Certificates of deposit    
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]    
Amortized cost 22,756 28,197
Unrealized gains 6 6
Unrealized losses (61) (92)
Fair value 22,701 28,111
Commercial paper    
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]    
Amortized cost 43,730 58,572
Unrealized gains 5 12
Unrealized losses (41) (72)
Fair value 43,694 58,512
Corporate debt securities    
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]    
Amortized cost 43,959 67,206
Unrealized gains   1
Unrealized losses (373) (786)
Fair value 43,586 66,421
U.S. government securities    
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]    
Amortized cost 16,849 2,000
Unrealized gains 36  
Unrealized losses (17) (35)
Fair value 16,868 $ 1,965
U.S. government agency securities    
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]    
Amortized cost 7,535  
Unrealized gains 18  
Fair value $ 7,553  
v3.23.1
Cash, cash equivalents and marketable securities (Contractual Final Maturities of Marketable Securities) (Details)
$ in Thousands
Mar. 31, 2023
USD ($)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost [Abstract]  
Due within one year, Amortized Cost $ 115,567
Due after one year through five years, Amortized Cost 19,262
Total, Amortized Cost 134,829
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value [Abstract]  
Due within one year, Fair Value 115,207
Due after one year through five years, Fair Value 19,195
Total, Fair Value $ 134,402
v3.23.1
Fair Value of Financial Instruments (Details) - USD ($)
$ in Thousands
Mar. 31, 2023
Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents $ 33,372 $ 34,601
Marketable securities 134,402 155,009
Certificates of deposit    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Marketable securities 22,701 28,111
Commercial paper    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Marketable securities 43,694 58,512
Corporate debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Marketable securities 43,586 66,421
U.S. government securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Marketable securities 16,868 1,965
U.S. government agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Marketable securities 7,553  
Money market funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents 25,302 24,578
Commercial paper    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents   2,491
Level 1 | Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents 25,302 24,578
Total financial assets 25,302 24,578
Level 1 | Recurring | Money market funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents 25,302 24,578
Level 2 | Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents   2,491
Marketable securities 134,402 155,009
Total financial assets 134,402 157,500
Level 2 | Recurring | Certificates of deposit    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Marketable securities 22,701 28,111
Level 2 | Recurring | Commercial paper    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents   2,491
Marketable securities 43,694 58,512
Level 2 | Recurring | Corporate debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Marketable securities 43,586 66,421
Level 2 | Recurring | U.S. government securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Marketable securities 16,868 $ 1,965
Level 2 | Recurring | U.S. government agency securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Marketable securities $ 7,553  
v3.23.1
Property and Equipment, net (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Dec. 31, 2022
Property, Plant and Equipment [Line Items]      
Total property and equipment $ 27,730   $ 27,668
Accumulated depreciation (6,131)   (5,153)
Total, property plant and equipment net 21,599   22,515
Depreciation expense 978 $ 883  
Laboratory equipment      
Property, Plant and Equipment [Line Items]      
Total property and equipment 10,379   9,972
Office equipment      
Property, Plant and Equipment [Line Items]      
Total property and equipment 601   601
Computer hardware and software.      
Property, Plant and Equipment [Line Items]      
Total property and equipment 1,128   1,090
Furniture and fixtures      
Property, Plant and Equipment [Line Items]      
Total property and equipment 1,208   1,208
Leasehold improvements      
Property, Plant and Equipment [Line Items]      
Total property and equipment 13,506   13,506
Construction in progress      
Property, Plant and Equipment [Line Items]      
Total property and equipment $ 908   $ 1,291
v3.23.1
Accrued Expenses and Other Current Liabilities (Details) - USD ($)
$ in Thousands
Mar. 31, 2023
Dec. 31, 2022
Accrued Expenses and Other Current Liabilities    
Professional fees $ 874 $ 602
Compensation and related benefits 3,370 8,446
Research and development 2,634 1,878
Property and equipment 29 85
Amount due to Catalent in connection with Letter Agreements 4,000  
Accrued expenses and other current liabilities $ 10,907 $ 11,011
v3.23.1
Leases (Details)
$ in Thousands
3 Months Ended
Mar. 31, 2023
USD ($)
item
Mar. 31, 2022
USD ($)
Lessee, Lease, Description [Line Items]    
Rent expense $ 800 $ 800
Future minimum lease payments    
2023 2,603  
2024 3,553  
2025 3,654  
2026 3,757  
2027 3,864  
Thereafter 29,679  
Total Undiscounted lease payments 47,110  
Less: imputed interest (20,158)  
Total Lease Liabilities 26,952  
Other current assets    
Lessee, Lease, Description [Line Items]    
Tenant improvements $ 100  
Maximum | Operating Leases For Office Space    
Lessee, Lease, Description [Line Items]    
Number of extension terms | item 2  
Extended term of new lease agreement 5 years  
Tenant improvement allowance $ 2,800  
Maximum | Operating Leases For Laboratory Space    
Lessee, Lease, Description [Line Items]    
Tenant improvement allowance $ 1,300  
v3.23.1
Commitments and Contingencies - Collaboration Agreements (Details)
$ in Millions
1 Months Ended 3 Months Ended 10 Months Ended
Aug. 03, 2020
USD ($)
Option
Aug. 31, 2021
Apr. 30, 2020
USD ($)
Jun. 30, 2019
Mar. 31, 2023
USD ($)
Mar. 31, 2022
USD ($)
May 01, 2024
USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]              
Development milestone payment         $ 0.0    
Catalent Maryland, Inc. (Catalent)              
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]              
Annual fee payable, term       5 years      
Period for which annual fee is payable     5 years        
Term of manufacturing and supply agreement     5 years        
Minimum amount agreed to purchase in batches of drug product     $ 10.6        
Accrued payments on collaboration         6.0    
Prepaid assets related to upfront payments         5.3    
Catalent Maryland, Inc. (Catalent) | General and administrative              
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]              
Expenses on elimination of prepaid asset         5.3    
Expense on write off         11.3    
Expense on write off of aggregate payments         6.0    
Catalent Maryland, Inc. (Catalent) | Subsequent Events              
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]              
Aggregate payments on collaboration             $ 6.0
Amended and restated agreement with Penn              
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]              
Annual fee payable $ 5.0            
Quarterly fee payable $ 1.3            
Number of CNS indications | Option 8            
Upfront payments $ 1.0            
Upfront fee payable upon clinical candidate designation 0.5            
Upfront fee due $ 0.5            
Payment made on option exercise           $ 1.5  
Amount payable per product candidate arising from the exploratory program for large CNS indications         39.0    
Sales milestone payments         55.0    
Amended and restated agreement with Penn | Minimum              
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]              
Collaboration agreement, tiered transaction fee percent   1.00%          
Amended and restated agreement with Penn | Maximum              
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]              
Collaboration agreement, tiered transaction fee percent   2.00%          
Amount payable per product candidate for rare, monogenic disorders         $ 16.5    
v3.23.1
Share-Based Compensation - Equity Incentive Plan & ESPP (Details)
3 Months Ended
Jan. 01, 2023
shares
Jan. 01, 2022
shares
Feb. 28, 2020
USD ($)
shares
Mar. 31, 2023
USD ($)
plan
shares
Mar. 31, 2022
USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Number of equity incentive plans | plan       3  
Number of shares purchased     4,000    
Share-based compensation expense | $       $ 2,784,000 $ 6,337,000
Equity Incentive Plan 2020          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Shares authorized       13,101,661  
Shares available for future grant       4,439,463  
Period till which there is automatic increase in rights granted under the Plan       10 years  
Percent of the total number of shares of the Company's common stock outstanding       5.00%  
Term of award       10 years  
Vesting period       4 years  
Additional number of common shares reserved for future issuance 2,730,735 2,712,249      
Equity Inducement Plan 2021          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Shares authorized       2,500,000  
Shares available for future grant       880,967  
Term of award       10 years  
Employee Stock Purchase Plan          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Shares authorized 1,981,766   1,981,766    
Shares available for future grant       1,666,061  
Additional number of common shares reserved for future issuance 546,147        
Period till which there is automatic increase in rights granted under ESPP     10 years    
Percentage of common stock outstanding     1.00%    
Percentage of stock purchase price     85.00%    
Percentage of maximum employee contribution     15.00%    
Maximum amount of common stock that can be purchased | $     $ 25,000    
Share-based compensation expense | $       $ 100,000 $ 100,000
v3.23.1
Share-Based Compensation - Share-based compensation expense (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based compensation expense $ 2,784 $ 6,337
Share-based compensation expense due to modifications 0  
Research and development    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based compensation expense 1,628 2,996
General and administrative    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based compensation expense $ 1,156 $ 3,341
v3.23.1
Share-Based Compensation - Stock Option Activity (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Dec. 31, 2022
Number of shares      
Outstanding, Beginning of period 11,411,390    
Granted 2,950,915    
Forfeited (752,733)    
Outstanding, Ending of period 13,609,572   11,411,390
Vested and Exercisable at December 31, 2022 6,011,809    
Vested or expected to vest at December 31, 2022 13,609,572    
Weighted average exercise price per share      
Outstanding, Beginning of period $ 9.01    
Granted 1.08    
Forfeited 13.69    
Outstanding, Ending of period 7.02   $ 9.01
Vested and Exercisable at December 31, 2022 10.96    
Vested or expected to vest at December 31, 2022 $ 7.02    
Weighted average remaining contractual term (years)      
Outstanding 7 years 4 months 24 days   7 years 1 month 6 days
Vested and Exercisable at December 31, 2022 5 years 1 month 6 days    
Vested or expected to vest at December 31, 2022 7 years 4 months 24 days    
Number of share options unvested and exercisable during the period 70,456    
Weighted average grant date fair value of options granted $ 0.83 $ 3.45  
Unrecognized compensation expense related to unvested stock option awards $ 21.9    
Weighted average period for recognition 2 years 2 months 12 days    
v3.23.1
Share-Based Compensation - Assumptions Used in Determining Fair Value & Early exercise of Stock Options (Details)
3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]    
Expected volatility 92.40% 95.40%
Risk-free interest rate 3.50% 1.50%
Expected term 6 years 6 years
v3.23.1
Share-Based Compensation - Restricted Stock Units (Details) - Unvested restricted stock units - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended
Mar. 31, 2023
Dec. 31, 2022
Number of shares    
Unvested balance, Beginning 1,229,166  
Vested (12,000)  
Forfeited (23,500)  
Unvested balance, Ending 1,193,666  
Weighted average grant date fair value    
Unvested balance, Weighted average grant date fair value, Beginning $ 2.85 $ 2.98
Vested, Weighted average grant date fair value 21.85  
Forfeited, Weighted average grant date fair value 2.40  
Unvested balance, Weighted average grant date fair value, Ending $ 2.85  
Total unrecognized expense $ 2.4  
Weighted-average remaining contractual term 1 year 6 months