Evelo Biosciences (EVLO) 10-Q 14 Nov 22 2022 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2022	Nov. 08, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2022
Document Transition Report	false
Entity File Number	001-38473
Entity Registrant Name	Evelo Biosciences, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-5594527
Entity Address, Address Line One	620 Memorial Drive
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02139
City Area Code	(617)
Local Phone Number	577-0300
Title of 12(b) Security	Common Stock,$0.001 par value per share
Trading Symbol	EVLO
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		109,614,598
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001694665
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 69,053	$ 68,441
Prepaid expenses and other current assets	3,274	2,585
Total current assets	72,327	71,026
Property and equipment, net	5,455	6,622
Right of use asset - operating lease	7,398	8,910
Other assets	1,156	1,313
Total assets	86,336	87,871
Current liabilities:
Debt, current portion	10,095	0
Accounts payable	1,550	1,601
Accrued expenses	12,478	13,068
Operating lease liability, current portion	2,177	1,951
Other current liabilities	617	742
Total current liabilities	26,917	17,362
Noncurrent liabilities:
Debt, net of current portion	36,650	46,557
Operating lease liability, net of current portion	5,935	7,785
Deferred revenue	7,500	7,500
Total liabilities	77,002	79,204
Commitments and contingencies (Note 9)
Stockholder’s equity:
Preferred stock, $0.001 par value; 10,000,000 shares authorized; no shares issued or outstanding as of September 30, 2022 and December 31, 2021, respectively	0	0
Common stock, $0.001 par value; 200,000,000 shares authorized; 108,473,091 and 53,576,454 shares issued and outstanding as of September 30, 2022 and December 31, 2021, respectively	108	54
Additional paid-in capital	514,907	423,308
Accumulated deficit	(505,681)	(414,695)
Total stockholders’ equity	9,334	8,667
Total liabilities and stockholders’ equity	$ 86,336	$ 87,871

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, authorized (in shares)	10,000,000	10,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	108,473,091	53,576,454
Common stock, shares outstanding (in shares)	108,473,091	53,576,454

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Operating expenses:
Research and development	$ 21,928	$ 22,599	$ 62,470	$ 64,762
General and administrative	7,126	10,111	24,909	23,075
Total operating expenses	29,054	32,710	87,379	87,837
Loss from operations	(29,054)	(32,710)	(87,379)	(87,837)
Other income (expense):
Interest expense, net	(788)	(1,023)	(2,835)	(2,602)
Loss on extinguishment of debt	0	0	0	(3,226)
Other miscellaneous income (expense), net	(615)	159	(386)	472
Total other expense, net	(1,403)	(864)	(3,221)	(5,356)
Loss before income taxes	(30,457)	(33,574)	(90,600)	(93,193)
Income tax expense	(107)	(156)	(386)	(331)
Net loss	$ (30,564)	$ (33,730)	$ (90,986)	$ (93,524)
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.28)	$ (0.63)	$ (1.14)	$ (1.77)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.28)	$ (0.63)	$ (1.14)	$ (1.77)
Weighted-average number of common shares outstanding, basic (in shares)	108,051,851	53,430,333	79,528,761	52,704,470
Weighted-average number of common shares outstanding, diluted (in shares)	108,051,851	53,430,333	79,528,761	52,704,470

Condensed Consolidated Statem_2

Condensed Consolidated Statement of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2020		47,470,119
Beginning balance at Dec. 31, 2020	$ 30,485	$ 47	$ 322,957	$ (292,519)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under Employee Stock Purchase Plan (in shares)		27,587
Issuance of common stock under Employee Stock Purchase Plan	90		90
Issuance of common stock, net (in shares)		5,814,734
Issuance of common stock, net	81,961	$ 6	81,955
Exercise of stock options (in shares)		45,299
Exercise of stock options	235		235
Stock-based compensation expense	3,264		3,264
Net loss	(28,196)			(28,196)
Ending balance (in shares) at Mar. 31, 2021		53,357,739
Ending balance at Mar. 31, 2021	87,839	$ 53	408,501	(320,715)
Beginning balance (in shares) at Dec. 31, 2020		47,470,119
Beginning balance at Dec. 31, 2020	30,485	$ 47	322,957	(292,519)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(93,524)
Ending balance (in shares) at Sep. 30, 2021		53,453,959
Ending balance at Sep. 30, 2021	33,076	$ 53	419,066	(386,043)
Beginning balance (in shares) at Mar. 31, 2021		53,357,739
Beginning balance at Mar. 31, 2021	87,839	$ 53	408,501	(320,715)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)		40,532
Exercise of stock options	330		330
Stock-based compensation expense	3,772		3,772
Issuance of common stock warrants	1,750		1,750
Net loss	(31,598)			(31,598)
Ending balance (in shares) at Jun. 30, 2021		53,398,271
Ending balance at Jun. 30, 2021	62,093	$ 53	414,353	(352,313)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under Employee Stock Purchase Plan (in shares)		18,771
Issuance of common stock under Employee Stock Purchase Plan	147		147
Vesting of restricted common stock (in shares)		9,850
Vesting of restricted common stock	0
Exercise of stock options (in shares)		27,067
Exercise of stock options	125		125
Stock-based compensation expense	4,441		4,441
Net loss	(33,730)			(33,730)
Ending balance (in shares) at Sep. 30, 2021		53,453,959
Ending balance at Sep. 30, 2021	$ 33,076	$ 53	419,066	(386,043)
Beginning balance (in shares) at Dec. 31, 2021	53,576,454	53,576,454
Beginning balance at Dec. 31, 2021	$ 8,667	$ 54	423,308	(414,695)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under Employee Stock Purchase Plan (in shares)		36,329
Issuance of common stock under Employee Stock Purchase Plan	129		129
Vesting of restricted common stock (in shares)		35,406
Vesting of restricted common stock	0
Stock-based compensation expense	4,275		4,275
Fees associated with public offering of common stock	(12)		(12)
Net loss	(29,861)			(29,861)
Ending balance (in shares) at Mar. 31, 2022		53,648,189
Ending balance at Mar. 31, 2022	$ (16,802)	$ 54	427,700	(444,556)
Beginning balance (in shares) at Dec. 31, 2021	53,576,454	53,576,454
Beginning balance at Dec. 31, 2021	$ 8,667	$ 54	423,308	(414,695)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ (90,986)
Ending balance (in shares) at Sep. 30, 2022	108,473,091	108,473,091
Ending balance at Sep. 30, 2022	$ 9,334	$ 108	514,907	(505,681)
Beginning balance (in shares) at Mar. 31, 2022		53,648,189
Beginning balance at Mar. 31, 2022	(16,802)	$ 54	427,700	(444,556)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net (in shares)		54,246,358
Issuance of common stock, net	78,982	$ 54	78,928
Vesting of restricted common stock (in shares)		16,278
Vesting of restricted common stock	0
Exercise of stock options (in shares)		42,494
Exercise of stock options	30		30
Stock-based compensation expense	3,999		3,999
Net loss	(30,561)			(30,561)
Ending balance (in shares) at Jun. 30, 2022		107,953,319
Ending balance at Jun. 30, 2022	35,648	$ 108	510,657	(475,117)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under Employee Stock Purchase Plan (in shares)		40,385
Issuance of common stock under Employee Stock Purchase Plan	72		72
Issuance of common stock, net (in shares)		475,000
Issuance of common stock, net	712	$ 0	712
Exercise of stock options (in shares)		4,387
Exercise of stock options	3		3
Stock-based compensation expense	3,463		3,463
Net loss	$ (30,564)			(30,564)
Ending balance (in shares) at Sep. 30, 2022	108,473,091	108,473,091
Ending balance at Sep. 30, 2022	$ 9,334	$ 108	$ 514,907	$ (505,681)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating activities
Net loss	$ (90,986,000)	$ (93,524,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	11,737,000	11,477,000
Depreciation expense	1,537,000	1,678,000
Non-cash interest expense	188,000	218,000
Non-cash lease expense	2,175,000	1,368,000
Loss on extinguishment of debt	0	3,226,000
Loss on disposal of property and equipment	232,000	5,000
Net foreign currency losses	1,012,000	0
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(799,000)	(63,000)
Accounts payable	(40,000)	1,075,000
Accrued expenses and other current liabilities	(814,000)	(404,000)
Operating lease liabilities	(2,287,000)	(1,414,000)
Deferred revenue	0	7,500,000
Other liabilities	0	(21,000)
Net cash used in operating activities	(78,045,000)	(68,879,000)
Investing activities
Purchases of property and equipment	(394,000)	(1,962,000)
Proceeds from sale of fixed assets	0	6,000
Net cash used in investing activities	(394,000)	(1,956,000)
Financing activities
Proceeds from issuance of common stock, net of issuance cost	79,682,000	81,961,000
Proceeds from the issuance of common stock under employee stock purchase plan and exercise of stock options	234,000	927,000
Proceeds from the issuance of long-term debt, net of issuance costs	0	14,778,000
Net cash provided by financing activities	79,916,000	97,666,000
Effect of exchange rate changes on cash and cash equivalents	(1,022,000)	0
Net increase in cash, cash equivalents and restricted cash	455,000	26,831,000
Cash, cash equivalents and restricted cash – beginning of period	69,754,000	70,420,000
Cash, cash equivalents and restricted cash – end of period	70,209,000	97,251,000
Supplemental disclosure of cash flow information
Cash paid for interest	2,963,000	2,383,000
Cash paid for taxes	592,000	9,000
Noncash investing and financing activities
Property and equipment additions included in accrued expenses	128,000	198,000
Issuance of common stock warrants	$ 0	$ 1,750,000

Organization

Organization	9 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Evelo Biosciences, Inc. ("Evelo," "we," "our," "us" or the "Company”) is a biotechnology company incorporated in Delaware on May 6, 2014. We are a clinical-stage biotechnology company focused on discovering and developing a new class of oral medicines that act on immune cells in the small intestine with systemic effects. We are advancing these investigational medicines with the aim of treating a broad range of inflammatory diseases, with an initial focus on psoriasis and atopic dermatitis. Our headquarters is located in Cambridge, Massachusetts. Since inception, we have devoted substantially all of our efforts to research and development and raising capital. We have not generated any product or license revenue related to our primary business purpose to date. We are subject to a number of risks similar to those of other development stage companies, including a dependence on key individuals, the need to develop commercially viable products, the competition from other companies, many of which are larger and better capitalized, and the need to obtain adequate additional financing to fund the development of our product candidates. We have incurred operating losses since inception and we expect such losses and negative operating cash flows to continue for the foreseeable future. As of September 30, 2022, we held cash and cash equivalents of $69.1 million and have an accumulated deficit of $505.7 million. Since inception, we have financed operations primarily with the proceeds from the issuance of common stock and since-redeemed preferred stock to equity investors, and from debt financing. In accordance with the Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40)

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification and ASU of the FASB. Use of Estimates The preparation of the unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Significant estimates and assumptions reflected in these unaudited condensed consolidated financial statements include, but are not limited to, estimates related to the application of Revenue from Contracts with Customers (Topic 606) ("ASC 606") to our collaboration agreement with Meddist Company Limited ("ALJ"), the accrual of research and development expenses, the expected future lives of property and equipment and the valuation of stock-based awards. We base our estimates on historical experience and market-specific or other relevant assumptions that we believe to be reasonable under the circumstances. Actual results could differ from those estimates. Unaudited Interim Financial Information Our unaudited condensed consolidated financial statements included herein have been prepared pursuant to the rules and regulations of the United States Securities and Exchange Commission (the “SEC”). The unaudited condensed consolidated financial statements include the accounts of our business and our wholly owned and controlled subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. In the opinion of management, the information furnished reflects all adjustments, all of which are of a normal and recurring nature, necessary for a fair presentation of the results for the reported interim periods. The results of operations for interim periods are not necessarily indicative of results to be expected for the full year or any other interim period. The accompanying condensed consolidated balance sheet as of December 31, 2021 has been derived from our audited consolidated financial statements for the year ended December 31, 2021. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to rules and regulations. However, we believe that the disclosures are adequate to make the information presented not misleading. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited annual consolidated financial statements and related notes in our Annual Report on Form 10-K for the year ended December 31, 2021. These unaudited condensed consolidated financial statements are prepared on the same basis as the audited financial statements. In the opinion of our management, the accompanying unaudited condensed consolidated financial statements contain all adjustments which are necessary to present fairly our financial position as of September 30, 2022, and the results of operations and stockholders' equity for the three and nine months ended September 30, 2022 and 2021. Such adjustments are of a normal and recurring nature. The results for the three and nine months ended September 30, 2022 are not necessarily indicative of the results to be realized for the year ending December 31, 2022, or for any future period. Subsequent Event Considerations We consider events or transactions that occur after the balance sheet date but prior to the issuance of the unaudited condensed consolidated financial statements to identify matters that require additional disclosure or that may significantly affect currently reported financial condition such as our judgments related to estimates. Subsequent events were evaluated as required. Emerging Growth Company Status We are an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 (the "JOBS Act"), and we may take advantage of reduced reporting requirements that are otherwise applicable to public companies until we are no longer an emerging growth company. Section 107 of the JOBS Act provides that an emerging growth company can take advantage of the extended transition period afforded by the JOBS Act for the implementation of new or revised accounting standards. We elected to use the extended transition period for complying with new or revised accounting standards and, as a result of this election, our unaudited condensed consolidated financial statements may not be comparable to companies that comply with public company effective dates. We may take advantage of these exemptions up until the last day of the fiscal year following the fifth anniversary of our IPO or such earlier time that we no longer are an emerging growth company. We would cease to be an emerging growth company if we have more than $1.235 billion in annual revenue, have more than $700.0 million in market value of our stock held by non-affiliates (and have been a public company for at least 12 months and have filed one annual report on Form 10-K), or have issued more than $1.0 billion of non-convertible debt securities over a three-year period. Concentrations of Credit Risk and Off-Balance Sheet Risk Financial instruments that potentially expose us to concentrations of credit risk primarily consist of cash and cash equivalents. We place our operating cash in demand deposit accounts at a single financial institution which have exceeded and are expected to continue to exceed federally insured limits. Our money market funds are held in an investment account at an affiliate institution. As of September 30, 2022 and December 31, 2021, we had no off-balance sheet risk such as foreign exchange contracts, option contracts, derivatives or foreign currency hedging arrangements. Comprehensive Loss Comprehensive loss consists of net loss and changes in equity during a period arising from transactions and other equity and circumstances, of which we have none. Our comprehensive loss equals our net loss for all periods presented. Cash, Cash Equivalents and Restricted Cash Cash equivalents are highly liquid investments that are readily convertible into cash with original maturities of three months or less, which consist of cash held in banks and funds held in money market accounts. Cash equivalents are stated at cost, which approximates market value. Our restricted cash consists of the deposits held for the building lease for our office and laboratory premises and for our credit card facility. As of September 30, 2022 and December 31, 2021 we had $1.2 million and $1.3 million, respectively, in noncurrent restricted cash included within other assets recorded on the unaudited condensed consolidated balance sheets. The following reconciles cash, cash equivalents and restricted cash as of September 30, 2022 and 2021, as presented on our statements of cash flows to the related balance sheet accounts (in thousands): September 30, 2022 2021 Cash and cash equivalents: Cash $ 10,363 $ 3,359 Money market funds 58,690 92,579 Total cash and cash equivalents 69,053 95,938 Restricted cash 1,156 1,313 Cash, cash equivalents and restricted cash $ 70,209 $ 97,251 Research and Development Costs Research and development costs are expensed in the period incurred. Research and development expenses consist of both internal and external costs associated with the development of our product candidates, such as payroll, consulting and manufacturing costs associated with the development of our product candidates. Costs for certain development activities, such as clinical trials and manufacturing development activities, are recognized based on an evaluation of the progress to completion of specific tasks using data such as patient enrollment, clinical site activations, and information provided to us by our vendors on their actual costs incurred or level of effort expended. Payments for these activities are based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected on the unaudited condensed consolidated balance sheets as prepaid or accrued research and development expenses. Segments We have one operating segment. Our chief operating decision maker, our Chief Executive Officer, manages our operations on a consolidated basis for the purposes of allocating resources. Recently Adopted Accounting Pronouncements Debt with Conversion and Other Options On August 5, 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU-2020-06”), which simplifies the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity’s own equity. The guidance simplifies the evaluation of whether a contract in the issuer’s own equity can be classified in equity or an embedded feature qualifies for the derivative scope exception. We adopted the guidance for the year beginning January 1, 2022. The adoption has no impact on our unaudited condensed consolidated financial statements and related disclosures. Codification Improvements In October 2020, the FASB issued ASU No. 2020-10 - Codification Improvements . The amendments improve the codification by having all disclosure-related guidance available in the disclosure sections of the codification and also include various other minor amendments. We adopted the guidance for the year beginning January 1, 2022, with no impact on our unaudited condensed consolidated financial statements and related disclosures. Accounting Pronouncements Issued and Not Adopted Financial Instruments - Credit Losses In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326) — Measurement of Credit Losses on Financial Instruments , which was subsequently updated (together “ASU 2016-13”). The provisions of ASU 2016-13 modify the impairment model to utilize an expected loss methodology in place of the currently used incurred loss methodology, and require a consideration of a broader range of reasonable and supportable information to inform credit loss estimates. ASU 2016-13 will be effective for us on January 1, 2023, with early adoption permitted. We are currently evaluating the potential impact that this standard may have on our financial position and results of operations, as well as the timing of our adoption of this standard.

ALJ Collaborative Agreement

ALJ Collaborative Agreement	9 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ALJ Collaborative Agreement	ALJ Collaborative Agreement In March 2021, we entered into a collaborative commercialization and license agreement (“ALJ Agreement”) with ALJ. Pursuant to the ALJ Agreement, we granted to ALJ an exclusive, non-transferable, sublicensable license to our product candidate EDP1815. In consideration for the rights granted under the ALJ Agreement, ALJ was obligated to pay a one-time, non-refundable upfront fee of $7.5 million. The parties will also share the future operating profits and losses for certain products in certain territories equally (50:50) as well as certain development, regulatory and commercialization costs. We have concluded that the delivery of the license to ALJ shall be accounted for under ASC 606. The development, regulatory and commercialization activities within the territories shall be accounted for under the FASB guidance of Collaborative Arrangements (Topic 808) ("ASC 808"). We have recognized no revenue under the ALJ Agreement to date as we have yet to undertake any of our performance obligations within the agreement. The $7.5 million upfront fee is recorded as deferred revenue as a non-current liability in the accompanying unaudited condensed consolidated balance sheets because the performance obligation is not expected to be completed within the next twelve months. We anticipate payments under the cost-sharing or profit and loss sharing arrangements will be classified in the statement of operations consistent with the guidance of ASC 808. To date, we have neither received nor incurred any such payments. Mayo Foundation for Medical Education and Research In August 2017, we and the Mayo Clinic entered into a license agreement which was subsequently amended. Under the agreement, the Mayo Clinic granted us (i) an exclusive, worldwide, sublicensable license under the Mayo Clinic’s rights to certain intellectual property and microbial strains and (ii) a non-exclusive, worldwide, sublicensable license to certain related know-how to develop and commercialize certain microbial strains and licensed products incorporating such strains. As consideration, we paid a nonrefundable upfront fee of $0.3 million and are obligated to pay annual license maintenance fees. The nonrefundable upfront fees were expensed to research and development expense in 2017. Annual maintenance fees are expensed as incurred over the term of the agreement. We may owe the Mayo Clinic milestone payments upon the achievement of certain milestones up to a maximum of $59.1 million in the aggregate, as well as royalties on net sales of licensed products in low single-digit percentages. As of September 30, 2022, we incurred milestone payments since inception of approximately $0.3 million and no amounts are currently due. University of Chicago In March 2016, we and the University of Chicago entered into a patent license agreement (“2016 University of Chicago Agreement”). Under the agreement, the University of Chicago granted us (i) an exclusive, royalty-bearing and sublicensable license to certain patent rights related to the administration of microbes to treat cancer and (ii) a non-exclusive, royalty-bearing, sublicensable license to access technical information for the development and commercialization of microbial products to treat cancer in combination with checkpoint inhibitors. As consideration, we paid a nonrefundable upfront fee of less than $0.5 million and were obligated to pay annual license maintenance fees. The nonrefundable upfront fees were expensed to research and development expense in 2016. Annual maintenance fees were expensed as incurred over the term of the agreement. As of September 30, 2022, we incurred milestone payments since inception of approximately $0.4 million and no amounts are currently due.

Leases

Leases	9 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Leases	Leases In January 2018, we entered into an operating sublease arrangement for approximately 40,765 square feet of office and research and development space at 620 Memorial Drive, Cambridge, MA 02139, extending through September 2025. The lease requires a security deposit which we fulfill with a standing letter of credit secured by restricted cash on deposit. For each of the three months ended September 30, 2022 and 2021, we recorded rent expense of $0.7 million. For each of the nine months ended September 30, 2022 and 2021, we recorded rent expense of $2.2 million. Lease amounts reported in the condensed consolidated balance sheets and the weighted-average lease term and discount rate information were as follows (in thousands): September 30, 2022 December 31, 2021 Assets: Operating lease right-of-use assets $ 7,398 $ 8,910 Liabilities: Operating lease liabilities, current 2,177 1,951 Operating lease liabilities, noncurrent 5,935 7,785 Total lease liabilities $ 8,112 $ 9,736 Weighted-average remaining lease term 3 years 3.75 years Weighted-average discount rate 9.5 % 9.5 %

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The following presents the fair value hierarchy for financial assets measured at fair value on a recurring basis as of September 30, 2022 (in thousands): Total Level 1 Assets: Money market funds included in cash and cash equivalents $ 58,690 $ 58,690 Total $ 58,690 $ 58,690 The following presents the fair value hierarchy for financial assets measured at fair value on a recurring basis as of December 31, 2021 (in thousands): Total Level 1 Assets: Money market funds included in cash and cash equivalents $ 66,989 $ 66,989 Total $ 66,989 $ 66,989 Cash held in money market funds are invested in a fund comprised of U.S. government securities and instruments. As of September 30, 2022 and December 31, 2021, our financial assets measurable at fair value consisted entirely of money market funds measured at Level 1. We held no financial liabilities measurable at fair value.

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2022
Payables and Accruals [Abstract]
Accrued Expenses	Accrued Expenses Accrued expenses recorded on the unaudited condensed consolidated balance sheets consist of the following (in thousands): September 30, 2022 December 31, 2021 External research and development expenses $ 5,637 $ 4,895 Payroll and related expenses 5,615 6,412 Professional fees 732 1,013 Other 494 748 Total accrued expenses $ 12,478 $ 13,068

Loan and Security Agreements

Loan and Security Agreements	9 Months Ended
	Sep. 30, 2022
Debt Disclosure [Abstract]
Loan and Security Agreements	Loan and Security Agreements In July 2019, we entered into a loan and security agreement with K2 HealthVentures LLC and others (collectively, "K2HV"), under which K2HV agreed to extend term loans of up to $45.0 million in three tranches. The initial tranche of $20.0 million was funded in July 2019. The second tranche of $10.0 million was funded in July 2020. The availability of the third tranche of $15.0 million expired in January 2021. The facility was amended in June 2021 (the "Amended Credit Facility"), to supersede the expired $15.0 million third tranche commitment with a new $15.0 million fourth tranche commitment, which we drew down in June 2021. The Amended Credit Facility resulted in a debt extinguishment for accounting purposes, and we recorded a loss on the extinguishment of debt of $3.2 million in the quarterly period end ed June 30, 2021, equaling the difference between the fair value for reacquisition of the new debt and the carrying amount of the existing debt. In connection with the Amended Credit Facility, we issued to K2 HealthVentures Equity Trust LLC, an affiliate of K2HV, a warrant to purchase up to 139,770 shares of our common stock (the "Warrant") at a Warrant Price (as defined in the Warrant) of $13.30 per share . In addition, we provided K2HV the option (the "Conversion Option"), exercisable at any time, to convert at a Conversion Price (as defined in the Amended Credit Facility) of $13.30 per share up to $5.0 million of loan principal outstanding into up to 375,940 shares of our common stock. Se e Note 10 - Stockholders' Equity. Interest on the outstanding loan balance accrues at a variable annual rate equal to the greater of (i) 8.65% and (ii) the prime rate plus 3.15%. Terms are for interest-only payments on a monthly basis through February 2023. Thereafter, terms provide for equal monthly payments of principal plus interest until the loans mature in August 2024 whereupon the remaining balance is due and payable. Pursuant to the Amended Credit Facility, we elected to adjust the repayment schedule such that commencing on March 1, 2023, we will make consecutive equal monthly payments of principal and accrued and unpaid interest based on a notional thirty month repayment period. The loan maturity date remains August 1, 2024 and any outstanding principal and unpaid interest is due at maturity. Upon final payment or prepayment of the loans, the terms of the Amended Credit Facility required us to pay a final payment ("Final Payment") equal to 4.8% of the aggregate original principal amount of the loans borrowed. Borrowings under the Amended Credit Facility are collateralized by substantially all our tangible personal property along with our equity interests in our subsidiaries. The Amended Credit Facility contains customary representations, warranties and covenants . During our debt covenant compliance review applicable to periods in the third quarter of 2022, we identified certain Events of Default (as defined in the Amended Credit Facility) resulting from non-compliance with certain provisions of the Amended Credit Facility. Under the Amended Credit Facility, Events of Default may entitle the lenders to default interest, the ability to terminate the facility and the ability to accelerate repayment of any outstanding loans in full. Subsequent to September 30, 2022, K2HV agreed to waive all identified Events of Default, thereby waiving its right to default interest and its ability to terminate the facility and accelerate repayment of all outstanding loans in full. As a result of this waiver, the debt remains classified according to its contractual payment terms as of September 30, 2022 and we are compliant with all covenants. In connection with such waiver, on November 14, 2022, we and K2HV entered into a modification letter to the Amended Credit Facility whereby we agreed, among other things, to: (i) accelerate the Final Payment of $2.16 million such that it will become payable on December 12, 2022 (it would have otherwise been due at maturity, at the time of a refinancing, or at the time of payment of final principal); (ii) amend and restate the Warrant to change the Warrant Price to $2.00 per share and increase the Number of Shares subject to the Warrant to 663,750; and (iii) with respect to the Conversion Option, restate the Conversion Price to $2.00 per share, such that K2HV may now convert up to $5.0 million of loan principal outstanding into up to 2,500,000 shares of our common stock. There is no impact of these agreed amended terms on the financial statements for any periods presented in this Quarterly Report on Form 10-Q as the amendments are effective subsequent to September 30, 2022. The minimum future loan payments under the Amended Credit Facility as of September 30, 2022, prior to the latest amendment described above, are as follows (in thousands): Remainder of 2022 $ 1,050 2023 17,618 2024 35,001 Total minimum payments 53,669 Less: amounts representing interest and discount (6,924) Total debt $ 46,745

In-License Agreements

In-License Agreements	9 Months Ended
	Sep. 30, 2022
Research and Development [Abstract]
In-License Agreements	ALJ Collaborative Agreement In March 2021, we entered into a collaborative commercialization and license agreement (“ALJ Agreement”) with ALJ. Pursuant to the ALJ Agreement, we granted to ALJ an exclusive, non-transferable, sublicensable license to our product candidate EDP1815. In consideration for the rights granted under the ALJ Agreement, ALJ was obligated to pay a one-time, non-refundable upfront fee of $7.5 million. The parties will also share the future operating profits and losses for certain products in certain territories equally (50:50) as well as certain development, regulatory and commercialization costs. We have concluded that the delivery of the license to ALJ shall be accounted for under ASC 606. The development, regulatory and commercialization activities within the territories shall be accounted for under the FASB guidance of Collaborative Arrangements (Topic 808) ("ASC 808"). We have recognized no revenue under the ALJ Agreement to date as we have yet to undertake any of our performance obligations within the agreement. The $7.5 million upfront fee is recorded as deferred revenue as a non-current liability in the accompanying unaudited condensed consolidated balance sheets because the performance obligation is not expected to be completed within the next twelve months. We anticipate payments under the cost-sharing or profit and loss sharing arrangements will be classified in the statement of operations consistent with the guidance of ASC 808. To date, we have neither received nor incurred any such payments. Mayo Foundation for Medical Education and Research In August 2017, we and the Mayo Clinic entered into a license agreement which was subsequently amended. Under the agreement, the Mayo Clinic granted us (i) an exclusive, worldwide, sublicensable license under the Mayo Clinic’s rights to certain intellectual property and microbial strains and (ii) a non-exclusive, worldwide, sublicensable license to certain related know-how to develop and commercialize certain microbial strains and licensed products incorporating such strains. As consideration, we paid a nonrefundable upfront fee of $0.3 million and are obligated to pay annual license maintenance fees. The nonrefundable upfront fees were expensed to research and development expense in 2017. Annual maintenance fees are expensed as incurred over the term of the agreement. We may owe the Mayo Clinic milestone payments upon the achievement of certain milestones up to a maximum of $59.1 million in the aggregate, as well as royalties on net sales of licensed products in low single-digit percentages. As of September 30, 2022, we incurred milestone payments since inception of approximately $0.3 million and no amounts are currently due. University of Chicago In March 2016, we and the University of Chicago entered into a patent license agreement (“2016 University of Chicago Agreement”). Under the agreement, the University of Chicago granted us (i) an exclusive, royalty-bearing and sublicensable license to certain patent rights related to the administration of microbes to treat cancer and (ii) a non-exclusive, royalty-bearing, sublicensable license to access technical information for the development and commercialization of microbial products to treat cancer in combination with checkpoint inhibitors. As consideration, we paid a nonrefundable upfront fee of less than $0.5 million and were obligated to pay annual license maintenance fees. The nonrefundable upfront fees were expensed to research and development expense in 2016. Annual maintenance fees were expensed as incurred over the term of the agreement. As of September 30, 2022, we incurred milestone payments since inception of approximately $0.4 million and no amounts are currently due.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Manufacture and Supply Agreement with Sacco S.r.l. In July 2019, we entered into an agreement with Sacco S.r.l. ("Sacco") pursuant to which Sacco will manufacture and supply single strain, non-genetically modified microbes intended for oral delivery or oral use in pharmaceutical products exclusively for us for a period of five years. Sacco may terminate the agreement if the provision of manufacturing services has been, or is scheduled to be, inactive for a consecutive period of six months. We agreed to pay Sacco an aggregate of €3.0 million, consisting of payments of €0.6 million annually during the exclusivity period. We have incurred annual exclusivity fees since inception of approximately €2.4 million, and no amounts are currently due. We have an additional contractual arrangement with an affiliate of Sacco for manufacturing that will require us to spend an aggregate minimum amount of €5.4 million, consisting of €1.5 million annually during each of 2022, 2023 and 2024 and €0.9 million on or before March 1, 2025. In addition to our manufacture and supply agreement with Sacco, we have other agreements including a collaborative agreement, sublease and license agreement which do or may obligate us to future funding commitments. See for example Note 3 - ALJ Collaborative Agreement, Note 4 - Leases and Note 8 - License Agreements. Litigation and Other Proceedings We may periodically become subject to legal proceedings and claims arising in connection with on-going business activities, including claims or disputes related to patents issued to us or that are pending. We currently are not a party to any material litigation and have established no contingency reserves for any litigation liability. On February 12, 2021, the European Patent Office issued a Communication of a Notice of Opposition for European patent EP 3223834, which is held by us. In July 2021, we filed our reply to the Notice of Opposition. In January 2022, the European Patent Office issued a preliminary opinion and a summons to oral proceedings. We filed our final written submission in July 2022, and the oral proceedings were held on September 14, 2022. The Opposition Board maintained claims that we presented in an auxiliary request in the oral proceedings. The deadline to appeal the Opposition Board’s decision is December 14, 2022. The patent at issue does not relate to any of our current product candidates, and any subsequent appeal is not expected to affect any of our current development plans.

Stockholders_ Equity

Stockholders’ Equity	9 Months Ended
	Sep. 30, 2022
Equity [Abstract]
Stockholders’ Equity	Stockholders’ Equity 2019 Shelf Registration and 2019 ATM Program In June 2019, we filed a Registration Statement on Form S-3 ("2019 Shelf Registration Statement") with the SEC for the registration and offering of common stock, preferred stock, debt securities, warrants and/or units or any combination thereof in the aggregate amount of up to $200.0 million for a period of up to three years from the date of effectiveness. We simultaneously entered into an "at-the-market" offering sales agreement ("2019 ATM") providing for the offering, issuance and sale for up to $50.0 million of common stock under the 2019 Shelf Registration Statement. During the year ended December 31, 2021, we issued 139,734 common shares under the 2019 ATM with offering prices ranging between $12.54 and $13.17 per share for gross proceeds of $1.8 million and net proceeds of $1.7 million. During the three and nine months ended September 30, 2022, we sold no shares of common stock under the 2019 ATM. The 2019 Shelf Registration Statement expired in June 2022, and we terminated the 2019 ATM in July 2022. 2021 Shelf Registration In August 2021, we filed a Registration Statement on Form S-3 (“2021 Shelf Registration Statement”) with the SEC for the registration and offering of common stock, preferred stock, debt securities, warrants and/or units or any combination thereof in the aggregate amount of up to $200.0 million for a period of up to three years from the date of effectiveness. No stock or securities registered thereunder were issued in the year ended December 31, 2021 or prior to our May 2022 Registered Direct Offering. May 2022 Registered Direct Offering In May 2022, we entered into a securities purchase agreement (the "Purchase Agreement") with certain purchasers named therein. Pursuant to the Purchase Agreement, we agreed to issue and sell to such purchasers in a registered direct offering an aggregate of 54,246,358 shares of common stock, including 393,834 shares acquired by our officers and directors and 28,253,422 shares acquired by related parties, at a purchase price of $1.46 per share, pursuant to the 2021 Shelf Registration Statement and a related prospectus supplement filed with the SEC. The closing of the registered direct offering occurred on May 27, 2022. The placement generated gross proceeds of $79.2 million. There were no underwriting or placement fees associated with the transaction. Legal, professional services and stock transfer fees totaled $0.2 million and were capitalized to additional paid-in capital upon the sale of common stock. 2022 ATM Program In July 2022, we entered into an "at-the-market" offering sales agreement ("2022 ATM") providing for the offering, issuance and sale of up to $75.0 million of our common stock under the 2021 Shelf Registration Statement. During the three and nine months ended September 30, 2022, we issued 475,000 shares of common stock under the 2022 ATM at a weighted average price per share of $2.06 for aggregate net proceeds of $0.7 million after deducting commissions and other offering expenses paid by us.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation 2021 Inducement Plan In May 2021, our board of directors adopted the Evelo Biosciences, Inc. 2021 Employment Inducement Award Plan (the “Inducement Award Plan”) without stockholder approval pursuant to Rule 5635(c)(4) of the Nasdaq Stock Market LLC listing rules. As of September 30, 2022, 310,000 shares of common stock are available for future grant under the Inducement Award Plan. 2018 Incentive Award Plan In April 2018, our board of directors adopted, and our stockholders approved, the 2018 Incentive Award Plan (the "2018 Plan"), effective May 2018, under which we may grant cash and equity-based incentive awards to our employees, officers, directors, consultants and advisors. As of September 30, 2022, awards representing 769,311 shares were available for future grant under the 2018 Plan. Stock Options Stock options and awards granted to employees generally vest over a four-year period but may be granted with different vesting terms and have a term of 10 years. During the nine months ended September 30, 2022 and 2021, we granted stock options to purchase 3,083,755 and 3,472,149 shares of common stock, respectively, with a weighted-average grant-date fair value of $2.89 and $10.81 per share, respectively. As of September 30, 2022, total unrecognized compensation expense related to stock options was $26.6 million, which is expected to be recognized over a weighted-average period of 2.6 years. Restricted Stock Units We issue RSUs under the 2018 Plan and the 2021 Inducement Award Plan. Typically, each award of RSUs vests as to 25% on the first anniversary of the grant date, and either monthly thereafter or annually over three Stock-based compensation expense related to RSUs was $0.2 million and $0.4 million for the three months ended September 30, 2022 and 2021, respectively. Stock-based compensation expense related to RSUs was $0.9 million and $0.7 million for the nine months ended September 30, 2022 and 2021, respectively. There was a total of 51,684 and 14,777 RSUs that vested during the nine months ended September 30, 2022 and 2021, respectively. 2018 Employee Stock Purchase Plan In April 2018, our board of directors adopted, and our stockholders approved, the 2018 Employee Stock Purchase Plan (“ESPP”), which became effective in May 2018. As of September 30, 2022, a total of 1,195,147 shares of common stock were reserved for issuance under the ESPP. The compensation expense recognized related to the ESPP for the three and nine months ended September 30, 2022 and 2021 was not material. There was a total of 76,714 and 46,358 shares, respectively, purchased under the ESPP during the nine months ended September 30, 2022 and 2021, respectively. Stock-Based Compensation Expense Stock-based compensation expense recorded in our unaudited condensed consolidated statements of operations consists of the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Research and development $ 1,694 $ 2,053 $ 5,431 $ 5,925 General and administrative 1,769 2,388 6,306 5,552 Total stock-based compensation expense 3,463 $ 4,441 11,737 $ 11,477

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share Basic and diluted net loss per common share is determined by dividing net loss attributable to common stockholders by the weighted-average common shares outstanding during the period, as follows (net loss in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Numerator Net loss $ (30,564) $ (33,730) $ (90,986) $ (93,524) Denominator Weighted average shares outstanding used in computing net loss per share 108,051,851 53,430,333 79,528,761 52,704,470 Net loss per share, basic and diluted $ (0.28) $ (0.63) $ (1.14) $ (1.77) We compute diluted net loss per common share by giving consideration to all potentially dilutive common shares, except where the effect of including such securities would be anti-dilutive. We have reported net losses since inception and, as such, have determined that all potentially dilutive common shares are anti-dilutive. Consequently, basic and diluted net loss per share of common stock were the same for all periods presented as the impact of all potentially dilutive securities outstanding was anti-dilutive. The following table presents securities excluded from the computation of diluted weighted-average shares outstanding for the periods presented, as they are anti-dilutive: September 30, 2022 2021 Unvested common stock from early exercise of options — 18,386 Stock options to purchase common stock 11,432,121 9,716,285 Warrants 139,770 139,770 RSUs 301,300 — Convertible debt (as-converted to common stock) 375,940 375,940 Common stock offering from ESPP 40,197 13,152 Total securities excluded 12,289,328 10,263,533

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2022
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Weatherden Advisory Services Agreement We receive clinical advisory services from Weatherden Ltd. (“Weatherden”) under agreements that were entered into during 2017 and 2018. Duncan McHale, our Chief Medical Officer, is a part owner of Weatherden. During each of the nine-month periods ended September 30, 2022 and 2021, we paid Weatherden $0.2 million. As of September 30, 2022 and December 31, 2021, the amounts owed to Weatherden under the supply of service agreement were approximately $0.1 million or less, respectively. Epstein Consulting Services Agreement In September 2019, we entered into a consulting agreement with David Epstein ("Consulting Agreement"), our former Chairman of the Board, for strategic advisory and other consulting services. The Consulting Agreement was amended in October 2020 and again in April 2021, and terminated pursuant to its terms on June 30, 2022. In accordance with the initial terms of the Consulting Agreement, Mr. Epstein was granted an option to purchase 75,000 shares of common stock, vesting in 36 equal monthly installments and subject to his continued provision of consulting services on the applicable vesting dates. Under the Consulting Agreement as amended in October 2020, Mr. Epstein was also entitled to receive (i) an annual equity award on each anniversary of the effective date of the Consulting Agreement in the form of an option to purchase shares of common stock having a grant date fair market value of approximately $0.2 million as determined by our board of directors in its discretion based on customary option pricing methodologies, vesting in 12 equal monthly installments and subject to his continued provision of consulting services on the applicable vesting date, and (ii) an aggregate annual cash consulting fee of $0.3 million. In the event the Consulting Agreement was renewed for a term of less than one year, the equity award and the number of shares of common stock would be adjusted proportionately to the length of the renewal term. In October 2020, in connection with the commencement of his second year of service as a consultant, Mr. Epstein was granted an option to purchase 44,743 shares of common stock, vesting in nine equal monthly installments and subject to his continued provision of consulting services on the vesting dates. Under the Consulting Agreement as amended in April 2021 and effective on June 30, 2021, Mr. Epstein was entitled to receive RSUs having an aggregate grant date fair value of approximately $0.5 million, as determined by our board of directors in its discretion based on a 10-day trailing average of the closing price of our common stock, as his sole compensation for his consulting services. The RSUs vested in 12 substantially equal monthly installments such that the RSUs became fully vested on June 30, 2022, in each case subject to Mr. Epstein's continued provision of consulting services on the applicable vesting date. In June 2022, terms of Mr. Epstein's unvested option grants were modified to allow immediate vesting upon his resignation as Chairman of the Board of Directors on June 30, 2022. All of the foregoing options and restricted stock units were or are subject to accelerated vesting under change in control provisions. Securities Purchase Agreement with Related Parties In May 2022, in connection with our registered direct offering, we entered into the Purchase Agreement with a group of purchasers including certain of our executive officers, members of our board of directors and other related parties. Of the 54,246,358 total shares offered, officers and directors purchased an aggregate of 393,834 shares and other related parties purchased an aggregate of 28,253,422 shares of our common stock for $1.46 per share, a price equal to the offering price per share of, and on equal terms as, common stock sold to the public. See Note 10 - Stockholders' Equity.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification and ASU of the FASB. The accompanying condensed consolidated balance sheet as of December 31, 2021 has been derived from our audited consolidated financial statements for the year ended December 31, 2021. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to rules and regulations. However, we believe that the disclosures are adequate to make the information presented not misleading. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited annual consolidated financial statements and related notes in our Annual Report on Form 10-K for the year ended December 31, 2021. These unaudited condensed consolidated financial statements are prepared on the same basis as the audited financial statements. In the opinion of our management, the accompanying unaudited condensed consolidated financial statements contain all adjustments which are necessary to present fairly our financial position as of September 30, 2022, and the results of operations and stockholders' equity for the three and nine months ended September 30, 2022 and 2021. Such adjustments are of a normal and recurring nature. The results for the three and nine months ended September 30, 2022 are not necessarily indicative of the results to be realized for the year ending December 31, 2022, or for any future period.
Use of Estimates	Use of Estimates The preparation of the unaudited condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Significant estimates and assumptions reflected in these unaudited condensed consolidated financial statements include, but are not limited to, estimates related to the application of Revenue from Contracts with Customers (Topic 606) ("ASC 606") to our collaboration agreement with Meddist Company Limited ("ALJ"), the accrual of research and development expenses, the expected future lives of property and equipment and the valuation of stock-based awards. We base our estimates on historical experience and market-specific or other relevant assumptions that we believe to be reasonable under the circumstances. Actual results could differ from those estimates.
Principles of Consolidation	All intercompany transactions and balances have been eliminated in consolidation. In the opinion of management, the information furnished reflects all adjustments, all of which are of a normal and recurring nature, necessary for a fair presentation of the results for the reported interim periods. The results of operations for interim periods are not necessarily indicative of results to be expected for the full year or any other interim period.
Subsequent Event Considerations	Subsequent Event ConsiderationsWe consider events or transactions that occur after the balance sheet date but prior to the issuance of the unaudited condensed consolidated financial statements to identify matters that require additional disclosure or that may significantly affect currently reported financial condition such as our judgments related to estimates. Subsequent events were evaluated as required.
Concentrations of Credit Risk and Off-Balance Sheet Risk	Concentrations of Credit Risk and Off-Balance Sheet Risk Financial instruments that potentially expose us to concentrations of credit risk primarily consist of cash and cash equivalents. We place our operating cash in demand deposit accounts at a single financial institution which have exceeded and are expected to continue to exceed federally insured limits. Our money market funds are held in an investment account at an affiliate institution. As of September 30, 2022 and December 31, 2021, we had no off-balance sheet risk such as foreign exchange contracts, option contracts, derivatives or foreign currency hedging arrangements.
Comprehensive Loss	Comprehensive Loss Comprehensive loss consists of net loss and changes in equity during a period arising from transactions and other equity and circumstances, of which we have none. Our comprehensive loss equals our net loss for all periods presented.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted CashCash equivalents are highly liquid investments that are readily convertible into cash with original maturities of three months or less, which consist of cash held in banks and funds held in money market accounts. Cash equivalents are stated at cost, which approximates market value. Our restricted cash consists of the deposits held for the building lease for our office and laboratory premises and for our credit card facility.
Research and Development Costs	Research and Development Costs Research and development costs are expensed in the period incurred. Research and development expenses consist of both internal and external costs associated with the development of our product candidates, such as payroll, consulting and manufacturing costs associated with the development of our product candidates. Costs for certain development activities, such as clinical trials and manufacturing development activities, are recognized based on an evaluation of the progress to completion of specific tasks using data such as patient enrollment, clinical site activations, and information provided to us by our vendors on their actual costs incurred or level of effort expended. Payments for these activities are based on the terms of the individual arrangements, which may differ
Segments	Segments We have one operating segment. Our chief operating decision maker, our Chief Executive Officer, manages our operations on a consolidated basis for the purposes of allocating resources.
Recently Adopted Accounting Pronouncements and Accounting Pronouncements Issued and Not Adopted	Recently Adopted Accounting Pronouncements Debt with Conversion and Other Options On August 5, 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity (“ASU-2020-06”), which simplifies the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity’s own equity. The guidance simplifies the evaluation of whether a contract in the issuer’s own equity can be classified in equity or an embedded feature qualifies for the derivative scope exception. We adopted the guidance for the year beginning January 1, 2022. The adoption has no impact on our unaudited condensed consolidated financial statements and related disclosures. Codification Improvements In October 2020, the FASB issued ASU No. 2020-10 - Codification Improvements . The amendments improve the codification by having all disclosure-related guidance available in the disclosure sections of the codification and also include various other minor amendments. We adopted the guidance for the year beginning January 1, 2022, with no impact on our unaudited condensed consolidated financial statements and related disclosures. Accounting Pronouncements Issued and Not Adopted Financial Instruments - Credit Losses In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326) — Measurement of Credit Losses on Financial Instruments , which was subsequently updated (together “ASU 2016-13”). The provisions of ASU 2016-13 modify the impairment model to utilize an expected loss methodology in place of the currently used incurred loss methodology, and require a consideration of a broader range of reasonable and supportable information to inform credit loss estimates. ASU 2016-13 will be effective for us on January 1, 2023, with early adoption permitted. We are currently evaluating the potential impact that this standard may have on our financial position and results of operations, as well as the timing of our adoption of this standard.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following reconciles cash, cash equivalents and restricted cash as of September 30, 2022 and 2021, as presented on our statements of cash flows to the related balance sheet accounts (in thousands): September 30, 2022 2021 Cash and cash equivalents: Cash $ 10,363 $ 3,359 Money market funds 58,690 92,579 Total cash and cash equivalents 69,053 95,938 Restricted cash 1,156 1,313 Cash, cash equivalents and restricted cash $ 70,209 $ 97,251
Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following reconciles cash, cash equivalents and restricted cash as of September 30, 2022 and 2021, as presented on our statements of cash flows to the related balance sheet accounts (in thousands): September 30, 2022 2021 Cash and cash equivalents: Cash $ 10,363 $ 3,359 Money market funds 58,690 92,579 Total cash and cash equivalents 69,053 95,938 Restricted cash 1,156 1,313 Cash, cash equivalents and restricted cash $ 70,209 $ 97,251

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Assets And Liabilities, Lessee	Lease amounts reported in the condensed consolidated balance sheets and the weighted-average lease term and discount rate information were as follows (in thousands): September 30, 2022 December 31, 2021 Assets: Operating lease right-of-use assets $ 7,398 $ 8,910 Liabilities: Operating lease liabilities, current 2,177 1,951 Operating lease liabilities, noncurrent 5,935 7,785 Total lease liabilities $ 8,112 $ 9,736
Lease, Cost	Weighted-average remaining lease term 3 years 3.75 years Weighted-average discount rate 9.5 % 9.5 %

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Measured at Fair Value	The following presents the fair value hierarchy for financial assets measured at fair value on a recurring basis as of September 30, 2022 (in thousands): Total Level 1 Assets: Money market funds included in cash and cash equivalents $ 58,690 $ 58,690 Total $ 58,690 $ 58,690 The following presents the fair value hierarchy for financial assets measured at fair value on a recurring basis as of December 31, 2021 (in thousands): Total Level 1 Assets: Money market funds included in cash and cash equivalents $ 66,989 $ 66,989 Total $ 66,989 $ 66,989

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2022
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses recorded on the unaudited condensed consolidated balance sheets consist of the following (in thousands): September 30, 2022 December 31, 2021 External research and development expenses $ 5,637 $ 4,895 Payroll and related expenses 5,615 6,412 Professional fees 732 1,013 Other 494 748 Total accrued expenses $ 12,478 $ 13,068

Loan and Security Agreements (T

Loan and Security Agreements (Tables)	9 Months Ended
	Sep. 30, 2022
Debt Disclosure [Abstract]
Schedule of Minimum Aggregate Future Loan Payments	The minimum future loan payments under the Amended Credit Facility as of September 30, 2022, prior to the latest amendment described above, are as follows (in thousands): Remainder of 2022 $ 1,050 2023 17,618 2024 35,001 Total minimum payments 53,669 Less: amounts representing interest and discount (6,924) Total debt $ 46,745

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Schedule of Stock-based Compensation Expense	Stock-based compensation expense recorded in our unaudited condensed consolidated statements of operations consists of the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Research and development $ 1,694 $ 2,053 $ 5,431 $ 5,925 General and administrative 1,769 2,388 6,306 5,552 Total stock-based compensation expense 3,463 $ 4,441 11,737 $ 11,477

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	Basic and diluted net loss per common share is determined by dividing net loss attributable to common stockholders by the weighted-average common shares outstanding during the period, as follows (net loss in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Numerator Net loss $ (30,564) $ (33,730) $ (90,986) $ (93,524) Denominator Weighted average shares outstanding used in computing net loss per share 108,051,851 53,430,333 79,528,761 52,704,470 Net loss per share, basic and diluted $ (0.28) $ (0.63) $ (1.14) $ (1.77)
Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Weighted-Average Shares Outstanding	The following table presents securities excluded from the computation of diluted weighted-average shares outstanding for the periods presented, as they are anti-dilutive: September 30, 2022 2021 Unvested common stock from early exercise of options — 18,386 Stock options to purchase common stock 11,432,121 9,716,285 Warrants 139,770 139,770 RSUs 301,300 — Convertible debt (as-converted to common stock) 375,940 375,940 Common stock offering from ESPP 40,197 13,152 Total securities excluded 12,289,328 10,263,533

Organization - Narrative (Detai

Organization - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 69,053	$ 68,441	$ 95,938
Accumulated deficit	$ 505,681	$ 414,695

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Narrative (Details) $ in Millions	9 Months Ended
	Sep. 30, 2022 USD ($) Segment	Dec. 31, 2021 USD ($)
Accounting Policies [Abstract]
Noncurrent restricted cash | $	$ 1.2	$ 1.3
Number of operating segments | Segment	1

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Cash and cash equivalents:
Cash	$ 10,363		$ 3,359
Money market funds	58,690		92,579
Total cash and cash equivalents	69,053	$ 68,441	95,938
Restricted cash	1,156		1,313
Cash, cash equivalents and restricted cash	$ 70,209	$ 69,754	$ 97,251	$ 70,420

ALJ Collaborative Agreement (De

ALJ Collaborative Agreement (Details) - USD ($) $ in Thousands	1 Months Ended
	Mar. 31, 2021	Sep. 30, 2022	Dec. 31, 2021
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue recognized		$ 7,500	$ 7,500
Transaction with party to collaborative arrangement | ALJ
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue recognized	$ 7,500	$ 7,500
Share of operating profits and losses and development, regulatory and commercialization costs.	50%

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Jan. 31, 2018 ft²
Leases [Abstract]
Area of leased office and research development space (in square feet) | ft²					40,765
Rent expense | $	$ 0.7	$ 0.7	$ 2.2	$ 2.2

Leases - Schedule of Consolidat

Leases - Schedule of Consolidated Balance Sheets and Lease Term (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Assets
Operating lease right-of-use assets	$ 7,398	$ 8,910
Liabilities:
Operating lease liability, current portion	2,177	1,951
Operating lease liabilities, non current	5,935	7,785
Total lease liabilities	$ 8,112	$ 9,736

Leases - Schedule of Minimum Ag

Leases - Schedule of Minimum Aggregate Future Lease Commitments (Details)	Sep. 30, 2022	Dec. 31, 2021
Leases [Abstract]
Weighted-average remaining lease term	3 years	3 years 9 months
Weighted-average discount rate	9.50%	9.50%

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Assets:
Money market funds included in cash and cash equivalents	$ 58,690		$ 92,579
Total	58,690	$ 66,989
Money market funds
Assets:
Money market funds included in cash and cash equivalents	58,690	66,989
Level 1
Assets:
Total	58,690	66,989
Level 1 | Money market funds
Assets:
Money market funds included in cash and cash equivalents	$ 58,690	$ 66,989

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
External research and development expenses	$ 5,637	$ 4,895
Payroll and related expenses	5,615	6,412
Professional fees	732	1,013
Other	494	748
Total accrued expenses	$ 12,478	$ 13,068

Loan and Security Agreements -

Loan and Security Agreements - Narrative (Details)	1 Months Ended		3 Months Ended			9 Months Ended
	Nov. 14, 2022 USD ($) shares $ / shares	Jun. 30, 2021 USD ($) $ / shares shares	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($) $ / shares shares	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Jul. 31, 2019 USD ($) tranche
Line of Credit Facility [Line Items]
Loss on extinguishment of debt			$ 0	$ 0		$ 0	$ 3,226,000
Principal amount of loans borrowed		4.80%
2019 Credit Facility
Line of Credit Facility [Line Items]
Interest expense			$ 1,100,000	$ 1,000,000		$ 3,200,000	$ 2,600,000
Amended Credit Facility | Warrants
Line of Credit Facility [Line Items]
Number of shares called by warrants (in shares) (up to) | shares		139,770			139,770
Amended Credit Facility | Convertible debt (as-converted to common stock)
Line of Credit Facility [Line Items]
Number of shares called by warrants (in shares) (up to) | shares		375,940			375,940
Line of Credit | 2019 Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity (up to)								$ 45,000,000
Number of tranches | tranche								3
Line of Credit | 2019 Credit Facility | Security And Loan Agreement, Tranche One
Line of Credit Facility [Line Items]
Maximum borrowing capacity (up to)								$ 20,000,000
Line of Credit | 2019 Credit Facility | Security And Loan Agreement, Tranche Two
Line of Credit Facility [Line Items]
Maximum borrowing capacity (up to)								10,000,000
Line of Credit | 2019 Credit Facility | Security And Loan Agreement, Tranche Three
Line of Credit Facility [Line Items]
Maximum borrowing capacity (up to)								15,000,000
Line of Credit | 2019 Credit Facility | Security And Loan Agreement, Tranche Four
Line of Credit Facility [Line Items]
Maximum borrowing capacity (up to)								$ 15,000,000
Line of Credit | Amended Credit Facility
Line of Credit Facility [Line Items]
Loss on extinguishment of debt					$ 3,200,000
Common stock exercise prices (in dollars per share) | $ / shares		$ 13.30			$ 13.30
Common stock at a conversion price (in dollars per share) | $ / shares		$ 13.30			$ 13.30
Convertible debt (up to)		$ 5,000,000			$ 5,000,000
Loan and security agreement, interest rate		8.65%			8.65%
Line of Credit | Amended Credit Facility | Subsequent Event
Line of Credit Facility [Line Items]
Number of shares called by warrants (in shares) (up to) | shares	663,750
Common stock exercise prices (in dollars per share) | $ / shares	$ 2
Common stock at a conversion price (in dollars per share) | $ / shares	$ 2
Convertible debt (up to)	$ 5,000,000
Final payment	$ 2,160,000
Number of shares issuable upon conversion | shares	2,500,000
Line of Credit | Amended Credit Facility | Prime Plus
Line of Credit Facility [Line Items]
Loan and security agreement, basis spread on interest rate		3.15%

Loan and Security Agreements _2

Loan and Security Agreements - Schedule of Minimum Aggregate Future Loan Payments (Details) - Line of Credit $ in Thousands	Sep. 30, 2022 USD ($)
Line of Credit Facility [Line Items]
Remainder of 2022	$ 1,050
2023	17,618
2024	35,001
Total minimum payments	53,669
Less: amounts representing interest and discount	(6,924)
Total debt	$ 46,745

In-License Agreements - Narrati

In-License Agreements - Narrative (Details) - USD ($)	1 Months Ended		62 Months Ended	79 Months Ended
	Aug. 31, 2017	Mar. 31, 2016	Sep. 30, 2022	Sep. 30, 2022
Mayo Clinic
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Non-refundable upfront fee	$ 300,000
Milestone payments upon achievement of certain development, regulatory, and commercial events (up to)			$ 300,000
Amount due under license agreement			0	$ 0
Mayo Clinic | Maximum
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Milestone payments upon achievement of certain development, regulatory, and commercial events (up to)	$ 59,100,000
University of Chicago Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Non-refundable upfront fee		$ 500,000
Amount due under license agreement			$ 0	0
Milestone payments for development and commercialization of licensed products				$ 400,000

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - Collaborative Arrangement - EUR (€) € in Millions	1 Months Ended	3 Months Ended	12 Months Ended			39 Months Ended
	Jul. 31, 2019	Mar. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2022
Sacco
Commitment And Contingencies [Line Items]
Term of collaboration arrangement	5 years
Period of inactive manufacturing services causing termination under collaborative arrangement	6 months
Aggregate amount due under collaborative arrangement	€ 3
Annual amount due under collaborative arrangement	0.6
Fee incurred under collaborative arrangement						€ 2.4
Affiliate Of Sacco
Commitment And Contingencies [Line Items]
Aggregate amount due under collaborative arrangement	€ 5.4
Affiliate Of Sacco | Forecast
Commitment And Contingencies [Line Items]
Collaboration arrangement additional fee incurred		€ 0.9	€ 1.5	€ 1.5	€ 1.5

Stockholders_ Equity (Details)

Stockholders’ Equity (Details) - USD ($)	1 Months Ended				3 Months Ended	9 Months Ended	12 Months Ended
	Jul. 31, 2022	May 31, 2022	Aug. 31, 2021	Jun. 30, 2019	Sep. 30, 2022	Sep. 30, 2022	Dec. 31, 2021
Class of Stock [Line Items]
Sale of stock, term (up to)			3 years	3 years
Number of shares sold in public offering (in shares)		54,246,358
Price of shares sold in public offering (in dollars per share)		$ 1.46
Registration Statement
Class of Stock [Line Items]
Maximum value of shares issued in transaction (up to)			$ 200,000,000	$ 200,000,000
2019 At-the-market
Class of Stock [Line Items]
Number of shares sold in public offering (in shares)					0	0
At-the-market
Class of Stock [Line Items]
Maximum value of shares issued in transaction (up to)				$ 50,000,000
Number of shares sold in public offering (in shares)					475,000	475,000	139,734
Price of shares sold in public offering (in dollars per share)	$ 2.06
Gross proceeds from transactions							$ 1,800,000
Net proceeds from issuance of common stock	$ 700,000						$ 1,700,000
Sale of stock, consideration authorized	$ 75,000,000
At-the-market | Minimum
Class of Stock [Line Items]
Price of shares sold in public offering (in dollars per share)							$ 12.54
At-the-market | Maximum
Class of Stock [Line Items]
Price of shares sold in public offering (in dollars per share)							$ 13.17
Purchase Agreement
Class of Stock [Line Items]
Number of shares sold in public offering (in shares)		54,246,358
Price of shares sold in public offering (in dollars per share)		$ 1.46
Net proceeds from issuance of common stock		$ 79,200,000
Fees associated with public offering of common stock		$ 200,000
Purchase Agreement | Affiliated Entity | Officers And Directors
Class of Stock [Line Items]
Number of shares sold in public offering (in shares)		393,834
Purchase Agreement | Affiliated Entity | Related Parties
Class of Stock [Line Items]
Number of shares sold in public offering (in shares)		28,253,422

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended		48 Months Ended
	Sep. 30, 2022	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense		$ 3,463	$ 4,441	$ 11,737	$ 11,477
2021 Stock Inducement Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock available for future grant (in shares)	310,000	310,000		310,000
2018 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock available for future grant (in shares)	769,311	769,311		769,311
Number of stock options granted (in shares)				3,083,755	3,472,149
Weighted average fair value of options granted (in dollars per share)				$ 2.89	$ 10.81
Unrecognized compensation expense	$ 26,600	$ 26,600		$ 26,600
Compensation cost not yet recognized, period for recognition				2 years 7 months 6 days
Stock Options | 2018 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)				4 years
Options granted, maximum expiration period (no more than)				10 years
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)						3 years
Number of stock options granted (in shares)				172,450	108,375
Weighted average fair value of options granted (in dollars per share)				$ 5.05	$ 15.50
Unrecognized compensation expense	$ 1,500	1,500		$ 1,500
Compensation cost not yet recognized, period for recognition				1 year 10 months 24 days
Total stock-based compensation expense		$ 200	$ 400	$ 900	$ 700
Number of shares vested (in shares)				51,684	14,777
RSUs | On first anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage						25%
Employee Stock Purchase Plan | 2018 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares authorized for issuance (in shares)	1,195,147
Number of shares issued for purchase (in shares)				76,714	46,358

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 3,463	$ 4,441	$ 11,737	$ 11,477
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	1,694	2,053	5,431	5,925
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 1,769	$ 2,388	$ 6,306	$ 5,552

Net Loss Per Share - Weighted-A

Net Loss Per Share - Weighted-Average Common Shares Outstanding (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Numerator
Net loss	$ (30,564)	$ (30,561)	$ (29,861)	$ (33,730)	$ (31,598)	$ (28,196)	$ (90,986)	$ (93,524)
Denominator
Weighted average shares used in computing net loss per share, basic (in shares)	108,051,851			53,430,333			79,528,761	52,704,470
Weighted average shares used in computing net loss per share, diluted (in shares)	108,051,851			53,430,333			79,528,761	52,704,470
Net loss per share, basic ( in dollars per share)	$ (0.28)			$ (0.63)			$ (1.14)	$ (1.77)
Net loss per share, diluted (in dollars per share)	$ (0.28)			$ (0.63)			$ (1.14)	$ (1.77)

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Weighted-Average Shares Outstanding (Details) - shares	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total number of securities excluded from computation of diluted weighted-average shares outstanding (in shares)	12,289,328	10,263,533
Unvested common stock from early exercise of options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total number of securities excluded from computation of diluted weighted-average shares outstanding (in shares)	0	18,386
Stock options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total number of securities excluded from computation of diluted weighted-average shares outstanding (in shares)	11,432,121	9,716,285
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total number of securities excluded from computation of diluted weighted-average shares outstanding (in shares)	139,770	139,770
RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total number of securities excluded from computation of diluted weighted-average shares outstanding (in shares)	301,300	0
Convertible debt (as-converted to common stock)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total number of securities excluded from computation of diluted weighted-average shares outstanding (in shares)	375,940	375,940
Common stock offering from ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total number of securities excluded from computation of diluted weighted-average shares outstanding (in shares)	40,197	13,152

Related Party Transactions - Na

Related Party Transactions - Narrative (Details) $ / shares in Units, $ in Millions	1 Months Ended			9 Months Ended
	May 31, 2022 $ / shares shares	Oct. 31, 2020 USD ($) installment shares	Sep. 30, 2019 installment shares	Sep. 30, 2022 USD ($) shares	Sep. 30, 2021 USD ($) shares	Dec. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)
Related Party Transaction [Line Items]
Amounts due to related party | $				$ 0.1		$ 0.1
Number of shares sold in public offering (in shares)	54,246,358
Price of shares sold in public offering (in dollars per share) | $ / shares	$ 1.46
Purchase Agreement
Related Party Transaction [Line Items]
Number of shares sold in public offering (in shares)	54,246,358
Price of shares sold in public offering (in dollars per share) | $ / shares	$ 1.46
Purchase Agreement | Other Related Parties
Related Party Transaction [Line Items]
Number of shares sold in public offering (in shares)	28,253,422
RSUs
Related Party Transaction [Line Items]
Number of stock options granted (in shares)				172,450	108,375
Weatherden Ltd
Related Party Transaction [Line Items]
Payment to related party | $				$ 0.2	$ 0.2
Mr. Epstein | RSUs
Related Party Transaction [Line Items]
Aggregate grant date fair value for restricted stock units | $							$ 0.5
Mr. Epstein | Consulting Agreement
Related Party Transaction [Line Items]
Number of stock options granted (in shares)		44,743	75,000
Option to purchase shares, vesting period, number of equal monthly installments | installment			36
Aggregate grant date fair value | $		$ 0.2
Annual equity award, vesting period, number of equal monthly installments | installment		12
Aggregate annual cash consulting fee | $		$ 0.3
Renewal term		1 year
Mr. Epstein | Consulting Agreement | Stock options to purchase common stock
Related Party Transaction [Line Items]
Annual equity award, vesting period, number of equal monthly installments | installment		9
Mr. Epstein | Consulting Agreement | RSUs
Related Party Transaction [Line Items]
Option to purchase shares, vesting period, number of equal monthly installments | installment		12
Period for trailing average closing common stock price		10 days
Affiliated Entity | Purchase Agreement | Officers And Directors
Related Party Transaction [Line Items]
Number of shares sold in public offering (in shares)	393,834