eFFECTOR Therapeutics (EFTR) 10-Q 8 Nov 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Oct. 31, 2021
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Registrant Name	eFFECTOR Therapeutics, Inc.
Entity Central Index Key	0001828522
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		40,371,726
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity File Number	001-39866
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	85-3306396
Entity Address, Address Line One	11120 Roselle Street
Entity Address, Address Line Two	Suite A
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92121
City Area Code	858
Local Phone Number	925-8215
Document Quarterly Report	true
Document Transition Report	false
Common Stock [Member]
Document Information [Line Items]
Trading Symbol	EFTR
Title of 12(b) Security	Common stock, $0.0001 par value per share
Security Exchange Name	NASDAQ
Warrant [Member]
Document Information [Line Items]
Trading Symbol	EFTRW
Title of 12(b) Security	Warrants to purchase common stock
Security Exchange Name	NASDAQ

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 54,768	$ 15,216
Prepaid expenses and other current assets	4,173	1,362
Total current assets	58,941	16,578
Property and equipment, net	21	34
Operating lease right-of-use assets	24	92
Other assets	950	0
Total assets	59,936	16,704
Current liabilities:
Accounts payable	321	347
Accrued expenses	2,748	1,984
Warrant liability	0	433
Term loans, net	0	5,907
Earn-out liability	43,250	0
Lease liabilities, current portion	28	108
Total current liabilities	46,347	8,779
Non-current term loans, net	18,663	6,946
Accrued final payment on term loans	1,100	0
Non-current warrant liability	1,495	0
Total liabilities	67,605	15,725
Commitments and contingencies
Stockholders' deficit:
Preferred stock, $0.0001 par value; 100,000,000 and zero shares authorized at September 30, 2021 and December 31, 2020 respectively; zero shares issued and outstanding as of September 30, 2021 and December 31, 2020	0	0
Common stock, $0.0001 par value; 1,000,000,000 shares authorized at September 30, 2021 and December 31, 2020; 40,669,373 shares issued and 40,369,373 shares issued and outstanding as of September 30, 2021; 1,445,065 shares issued and outstanding as of December 31, 2020	4	0
Additional paid-in capital	132,277	4,454
Accumulated deficit	(139,950)	(136,699)
Total stockholders' deficit	(7,669)	(132,245)
Total liabilities, convertible preferred stock, and stockholders' deficit	59,936	16,704
Series A Preferred Stock [Member]
Current liabilities:
Temporary equity carrying amount attributable to parent	0	46,567
Series B Preferred Stock [Member]
Current liabilities:
Temporary equity carrying amount attributable to parent	0	51,084
Series C Preferred Stock [Member]
Current liabilities:
Temporary equity carrying amount attributable to parent	$ 0	$ 35,573

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred Stock, Shares authorized	100,000,000	0
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock price per share	$ 0.0001	$ 0.0001
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	40,669,373	1,445,065
Common stock, shares outstanding	40,369,373	1,445,065
Series A Preferred Stock [Member]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred Stock, Shares authorized	0	14,056,840
Preferred stock, shares issued	0	11,563,819
Preferred stock, shares outstanding	0	11,563,819
Preferred Stock, liquidation preference, Value	$ 0	$ 46,900,000
Series B Preferred Stock [Member]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred Stock, Shares authorized	0	11,071,448
Preferred stock, shares issued	0	10,154,819
Preferred stock, shares outstanding	0	10,154,819
Preferred Stock, liquidation preference, Value	$ 0	$ 51,400
Series C Preferred Stock [Member]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred Stock, Shares authorized	0	7,346,140
Preferred stock, shares issued	0	6,734,590
Preferred stock, shares outstanding	0	6,734,590
Preferred Stock, liquidation preference, Value	$ 0	$ 35,800,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Total revenue	$ 427	$ 574	$ 1,119	$ 41,958
Operating expenses:
Research and development	5,022	6,780	13,562	17,231
General and administrative	4,119	1,063	7,052	3,289
Total operating expenses	9,141	7,843	20,614	20,520
Operating (loss) income	(8,714)	(7,269)	(19,495)	21,438
Other income (expense)
Interest income	1	3	2	65
Interest expense	(488)	(342)	(1,274)	(1,019)
Other income (expense), net	290	4	218	(68)
Change in fair value of earn-out liability	17,790	0	17,790	0
Loss on debt extinguishment	0	0	(492)	0
Total other income (expense)	17,593	(335)	16,244	(1,022)
Income (loss) before income taxes	8,879	(7,604)	(3,251)	20,416
Income tax expense	0	5	0	351
Net income (loss) and comprehensive income (loss)	8,879	(7,609)	(3,251)	20,065
Income allocable to participating securities	0	0	0	(19,502)
Net income (loss) attributable to common shareholders	$ 8,879	$ (7,609)	$ (3,251)	$ 563
Net income (loss) per share attributable to common shareholders:
Net income (loss) per share - Basic	$ 0.53	$ (5.29)	$ (0.49)	$ 0.40
Net income (loss) per share - diluted	$ 0.42	$ (5.29)	$ (0.49)	$ 0.39
Weighted-average common shares outstanding:
Weighted average common shares outstanding - basic	16,701,967	1,438,584	6,588,282	1,398,954
Weighted average common shares outstanding - diluted	20,067,715	1,438,584	6,588,282	2,505,240
Collaboration Revenue
Total revenue	$ 0	$ 574	$ 0	$ 41,958
Grant Revenue
Total revenue	$ 427	$ 0	$ 1,119	$ 0

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Deficit (Unaudited) - USD ($)	Total	Series A Preferred Stock [Member]	Series B Preferred Stock [Member]	Series C Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Previously Reported [Member]	Previously Reported [Member]Series A Preferred Stock [Member]	Previously Reported [Member]Series B Preferred Stock [Member]	Previously Reported [Member]Series C Preferred Stock [Member]	Previously Reported [Member]Common Stock [Member]	Previously Reported [Member]Additional Paid-in Capital [Member]	Previously Reported [Member]Accumulated Deficit [Member]	Revision of Prior Period, Adjustment [Member]Series A Preferred Stock [Member]	Revision of Prior Period, Adjustment [Member]Series B Preferred Stock [Member]	Revision of Prior Period, Adjustment [Member]Series C Preferred Stock [Member]	Revision of Prior Period, Adjustment [Member]Common Stock [Member]	Revision of Prior Period, Adjustment [Member]Additional Paid-in Capital [Member]
Balance at Dec. 31, 2019	$ (147,063,000)					$ 3,847,000	$ (150,910,000)	$ (147,063,000)				$ 1,000	$ 3,846,000	$ (150,910,000)				$ (1,000)	$ 1,000
Temporary Equity, Balance, shares at Dec. 31, 2019		11,563,819	10,154,819	6,734,590					119,744,594	105,154,241	69,737,402				108,180,775	94,999,422	63,002,812
Temporary Equity, Balance at Dec. 31, 2019		$ 46,567,000	$ 51,084,000	$ 35,573,000					$ 46,567,000	$ 51,084,000	$ 35,573,000
Balance, shares at Dec. 31, 2019					1,333,711							13,810,811						12,477,100
Stock option exercises	16,000					16,000
Stock option exercises, shares					18,915
Stock-based compensation expense	89,000					89,000
Net income (loss)	19,081,000						19,081,000
Balance at Mar. 31, 2020	(127,877,000)					3,952,000	(131,829,000)
Temporary Equity, Balance, shares at Mar. 31, 2020		11,563,819	10,154,819	6,734,590
Temporary Equity, Balance at Mar. 31, 2020		$ 46,567,000	$ 51,084,000	$ 35,573,000
Balance, shares at Mar. 31, 2020					1,352,626
Balance at Dec. 31, 2019	(147,063,000)					3,847,000	(150,910,000)	$ (147,063,000)				$ 1,000	$ 3,846,000	$ (150,910,000)				$ (1,000)	$ 1,000
Temporary Equity, Balance, shares at Dec. 31, 2019		11,563,819	10,154,819	6,734,590					119,744,594	105,154,241	69,737,402				108,180,775	94,999,422	63,002,812
Temporary Equity, Balance at Dec. 31, 2019		$ 46,567,000	$ 51,084,000	$ 35,573,000					$ 46,567,000	$ 51,084,000	$ 35,573,000
Balance, shares at Dec. 31, 2019					1,333,711							13,810,811						12,477,100
Stock option exercises	$ 108,000
Stock option exercises, shares	111,354
Net income (loss)	$ 20,065,000
Balance at Sep. 30, 2020	(126,546,000)					4,299,000	(130,845,000)
Temporary Equity, Balance, shares at Sep. 30, 2020		11,563,819	10,154,819	6,734,590
Temporary Equity, Balance at Sep. 30, 2020		$ 46,567,000	$ 51,084,000	$ 35,573,000
Balance, shares at Sep. 30, 2020					1,445,065
Balance at Mar. 31, 2020	(127,877,000)					3,952,000	(131,829,000)
Temporary Equity, Balance, shares at Mar. 31, 2020		11,563,819	10,154,819	6,734,590
Temporary Equity, Balance at Mar. 31, 2020		$ 46,567,000	$ 51,084,000	$ 35,573,000
Balance, shares at Mar. 31, 2020					1,352,626
Stock option exercises	72,000					72,000
Stock option exercises, shares					75,540
Stock-based compensation expense	99,000					99,000
Net income (loss)	8,593,000						8,593,000
Balance at Jun. 30, 2020	(119,113,000)					4,123,000	(123,236,000)
Temporary Equity, Balance, shares at Jun. 30, 2020		11,563,819	10,154,819	6,734,590
Temporary Equity, Balance at Jun. 30, 2020		$ 46,567,000	$ 51,084,000	$ 35,573,000
Balance, shares at Jun. 30, 2020					1,428,166
Stock option exercises	$ 20,000					20,000
Stock option exercises, shares	16,899				16,899
Stock-based compensation expense	$ 156,000					156,000
Net income (loss)	(7,609,000)						(7,609,000)
Balance at Sep. 30, 2020	(126,546,000)					4,299,000	(130,845,000)
Temporary Equity, Balance, shares at Sep. 30, 2020		11,563,819	10,154,819	6,734,590
Temporary Equity, Balance at Sep. 30, 2020		$ 46,567,000	$ 51,084,000	$ 35,573,000
Balance, shares at Sep. 30, 2020					1,445,065
Stock-based compensation expense	155,000					155,000
Net income (loss)	(5,854,000)						(5,854,000)
Balance at Dec. 31, 2020	$ (132,245,000)					4,454,000	(136,699,000)
Temporary Equity, Balance, shares at Dec. 31, 2020	28,453,228	11,563,819	10,154,819	6,734,590
Temporary Equity, Balance at Dec. 31, 2020		$ 46,567,000	$ 51,084,000	$ 35,573,000
Balance, shares at Dec. 31, 2020	1,445,065				1,445,065
Stock-based compensation expense	$ 188,000					188,000
Net income (loss)	(6,582,000)						(6,582,000)
Balance at Mar. 31, 2021	(138,639,000)					4,642,000	(143,281,000)
Temporary Equity, Balance, shares at Mar. 31, 2021		11,563,819	10,154,819	6,734,590
Temporary Equity, Balance at Mar. 31, 2021		$ 46,567,000	$ 51,084,000	$ 35,573,000
Balance, shares at Mar. 31, 2021					1,445,065
Balance at Dec. 31, 2020	$ (132,245,000)					4,454,000	(136,699,000)
Temporary Equity, Balance, shares at Dec. 31, 2020	28,453,228	11,563,819	10,154,819	6,734,590
Temporary Equity, Balance at Dec. 31, 2020		$ 46,567,000	$ 51,084,000	$ 35,573,000
Balance, shares at Dec. 31, 2020	1,445,065				1,445,065
Stock option exercises	$ 78,000
Stock option exercises, shares	72,940
Net income (loss)	$ (3,251,000)
Balance at Sep. 30, 2021	$ (7,669,000)				$ 4,000	132,277,000	(139,950,000)
Temporary Equity, Balance, shares at Sep. 30, 2021		0	0	0
Temporary Equity, Balance at Sep. 30, 2021		$ 0	$ 0	$ 0
Balance, shares at Sep. 30, 2021	40,369,373				40,369,373
Balance at Mar. 31, 2021	$ (138,639,000)					4,642,000	(143,281,000)
Temporary Equity, Balance, shares at Mar. 31, 2021		11,563,819	10,154,819	6,734,590
Temporary Equity, Balance at Mar. 31, 2021		$ 46,567,000	$ 51,084,000	$ 35,573,000
Balance, shares at Mar. 31, 2021					1,445,065
Stock option exercises	15,000					15,000
Stock option exercises, shares					15,451
Stock-based compensation expense	161,000					161,000
Net income (loss)	(5,548,000)						(5,548,000)
Balance at Jun. 30, 2021	(144,011,000)					4,818,000	(148,829,000)
Temporary Equity, Balance, shares at Jun. 30, 2021		11,563,819	10,154,819	6,734,590
Temporary Equity, Balance at Jun. 30, 2021		$ 46,567,000	$ 51,084,000	$ 35,573,000
Balance, shares at Jun. 30, 2021					1,460,516
Recapitalization Costs	51,974,000				$ 1,000	51,973,000
Recapitalization Costs, Share					10,347,611
Conversion of preferred stock into common stock	133,224,000	$ (46,567,000)	$ (51,084,000)	$ (35,573,000)	$ 3,000	133,221,000
Conversion of preferred stock into common stock, Share		(11,563,819)	(10,154,819)	(6,734,590)	28,453,228
Contingently issuable Earn-Out Shares	(61,040,000)					(61,040,000)
Stock option exercises	$ 63,000					63,000
Stock option exercises, shares	57,489				57,489
Cashless exercise of warrants	$ 857,000					857,000
Cashless exercise of warrants, share					50,529
Stock-based compensation expense	2,385,000					2,385,000
Net income (loss)	8,879,000						8,879,000
Balance at Sep. 30, 2021	$ (7,669,000)				$ 4,000	$ 132,277,000	$ (139,950,000)
Temporary Equity, Balance, shares at Sep. 30, 2021		0	0	0
Temporary Equity, Balance at Sep. 30, 2021		$ 0	$ 0	$ 0
Balance, shares at Sep. 30, 2021	40,369,373				40,369,373

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities:
Net income (loss)	$ (3,251)	$ 20,065
Adjustments to reconcile net (loss) income to cash (used in) provided by operating activities:
Depreciation and amortization expense	19	127
Stock-based compensation	2,734	344
Loss on debt extinguishment	492	0
(Gain) Loss on change in fair value of warrant liability	(213)	68
Gain on change in fair value of earn-out liability	(17,790)
Non-cash interest expense	221	93
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(2,249)	447
Other non-current assets	(950)
Accounts payable	(26)	560
Accrued expenses	1,145	(434)
Operating lease right-of-use assets and liabilities, net	(12)	(10)
Contract liabilities		42
Net cash (used in) provided by operating activities	(19,880)	21,302
Investing activities:
Proceeds from sale of fixed assets	607
Purchases of fixed assets	(6)
Net cash provided by investing activities	601	0
Financing activities:
Proceeds from issuance of common stock options	78	108
Issuance of term loans, net of issuance costs	19,835
Repayment of term loans	(13,940)	(500)
Proceeds from Business Combination, net of offering costs paid (see Note 3)	52,858
Net cash provided by (used in) financing activities	58,831	(392)
Net increase in cash and cash equivalents	39,552	20,910
Cash and cash equivalents at beginning of period	15,216	3,427
Cash and cash equivalents at end of period	54,768	24,337
Supplemental disclosure of cash flow information
Interest paid	951	745
Operating lease liabilities arising from obtaining right-of-use assets		$ 269
Conversion of preferred stock into common stock	133,224
Cashless Warrant Exercise	$ 857

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Basis of Presentation	1. Organization and Basis of Presentation Description of Business Locust Walk Acquisition Corp. ("LWAC”) was initially formed on October 2, 2020 as a Delaware corporation formed for the purpose of effecting a merger, capital stock exchange, asset acquisition, stock purchase, reorganization or other similar business transaction with one or more operating businesses. On May 26, 2021, LWAC entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Locust Walk Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of LWAC (“Merger Sub”), and eFFECTOR Therapeutics, Inc., a Delaware corporation (“ Old eFFECTOR”). Pursuant to the terms of the Merger Agreement, a business combination between LWAC and Old eFFECTOR was effected through the merger of the Merger Sub with and into Old eFFECTOR, with Old eFFECTOR surviving as the surviving company and a wholly-owned subsidiary of LWAC with the name of eFFECTOR Therapeutics Operations, Inc. On August 25, 2021, and in connection with the closing of the business combination (the "Business Combination"), LWAC was renamed eFFECTOR Therapeutics, Inc. ("eFFECTOR" or the "Company"). All outstanding preferred shares of Old eFFECTOR converted into common shares of Old eFFECTOR on a 1:1 basis, which were then converted, along with all outstanding common shares of Old eFFECTOR, into common shares of the surviving eFFECTOR company through application of an exchange ratio of approximately 0.09657 (the "Exchange Ratio"). The Company is a clinical-stage biopharmaceutical company focused on pioneering the discovery and development of a new class of oncology drugs the Company refers to as selective translation regulator inhibitors. The Company’s principal operations are in the United States, with its headquarters in San Diego, California. The Company has devoted substantially all of its resources to raising capital, identifying potential product candidates, establishing its intellectual property portfolio, conducting preclinical studies and clinical trials, establishing arrangements with third parties for the manufacture of its product candidates and related raw materials, and providing general and administrative support for these operations. The Company has not generated revenues from its principal operations through September 30, 2021. Basis of Presentation The accompanying unaudited condensed consolidated financial statements as of September 30, 2021 and for the three and nine months ended September 30, 2021 and 2020 have been prepared in accordance with U.S. generally accepted accounting principles (“US GAAP”) for interim financial information and pursuant to Article 10 of Regulation S-X of the Securities Act of 1933, as amended (the “Securities Act”). Accordingly, they do not include all of the information and notes required by US GAAP for complete financial statements. These unaudited financial statements include only normal and recurring adjustments that the Company believes are necessary to fairly state the Company’s financial position and the results of its operations and cash flows. The results for the three and nine months ended September 30, 2021 are not necessarily indicative of the results expected for the full fiscal year or any subsequent interim period. The balance sheet at December 31, 2020 has been derived from the audited financial statements at that date but does not include all the disclosures required by US GAAP for complete financial statements. Because all of the disclosures required by US GAAP for complete financial statements are not included herein, these unaudited financial statements and the notes accompanying them should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2020 included elsewhere in Form 424(b)(3) filed with the Securities and Exchange Commission (“SEC”) on October 5, 2021. The Business Combination was accounted for as a reverse recapitalization in accordance with U.S. GAAP. Under this method of accounting, LWAC was treated as the “acquired” Company and eFFECTOR is treated as the acquirer for financial reporting purposes. Accordingly, for accounting purposes, the Business Combination was treated as the equivalent of Old eFFECTOR issuing stock for the net assets of LWAC, accompanied by a recapitalization. The net assets of LWAC are stated at historical cost, with no goodwill or other intangible assets recorded. Old eFFECTOR was determined to be the accounting acquirer based on the following predominant factors:  Old eFFECTOR’s shareholders have a majority of the voting power of the combined company;  the Board and Management are primarily composed of individuals associated with Old eFFECTOR; and  Old eFFECTOR comprises all of the ongoing operations of the combined company. The consolidated assets, liabilities and results of operations prior to the Business Combination are those of Old eFFECTOR. The shares and corresponding capital amounts and income or losses per share, prior to the Business Combination, have been retroactively restated based on shares reflecting the Exchange Ratio established in the Business Combination. Liquidity The Company has a limited operating history and the sales and income potential of the Company’s business and market are unproven. The accompanying financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or amounts and classification of liabilities that may result from the outcome of this uncertainty. Management is required to perform a two-step analysis over its ability to continue as a going concern. Management must first evaluate whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern (step 1). If management concludes that substantial doubt is raised, management is also required to consider whether its plans alleviate that doubt (step 2). The Company has experienced net losses and negative cash flows from operating activities since its inception, aside from the year ended December 31, 2020, as a result of non-recurring revenue in connection with the Research Collaboration and License Agreement with Pfizer which rendered net income in 2020. The Company has an accumulated deficit of $ 140.0 million at September 30, 2021. For the nine months ended September 30, 2021, the Company used $ 19.9 million in cash for operations. At September 30, 2021, the Company had cash and cash equivalents of $ 54.8 million. Management anticipates that its expenses will increase significantly in connection with its ongoing activities to support its research and development efforts, and it expects to incur substantial operating losses and negative cash flows from operations for the foreseeable future. The Company believes that its $ 54.8 million of cash and cash equivalents held as of September 30, 2021 are sufficient to fund planned operations for at least twelve months from the date that these financial statements are issued, though the Company may pursue additional cash resources through public or private equity or debt financings. Management’s expectations with respect to its ability to fund current planned operations is based on estimates that are subject to risks and uncertainties. Its operating plan may change as a result of many factors currently unknown to management and there can be no assurance that the current operating plan will be achieved in the time frame anticipated by the Company, and it may need to seek additional funds sooner than anticipated. If adequate funds are not available to the Company on a timely basis, management may be required to delay, limit, reduce or terminate certain of its research, product development or future commercialization efforts, obtain funds through arrangements with collaborators on terms unfavorable to the Company, or pursue merger or acquisition strategies, all of which could adversely affect the holdings or the rights of its stockholders.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Grant Revenue The Company’s grant revenues are derived from a grant with the Defense Advanced Research Projects Agency (“DARPA”) through the University of California, San Francisco (“UCSF”). The Company recognizes DARPA Grant revenue as reimbursable grant costs are incurred up to pre-approved award limits within the budget period. The costs associated with these reimbursements are reflected as a component of research and development expense in the accompanying statements of operations. Billings in excess of receipts are included as a receivable recorded within prepaid expenses and other current assets on the balance sheets. Research and Development Costs Research and development expenses primarily consist of costs associated with the preclinical and clinical development of the Company’s product candidates. Research and development costs are expensed as incurred. Clinical Trial Accruals and Preclinical Studies The Company is required to estimate expenses resulting from our obligations under contracts with vendors and consultants, CROs and clinical sites in connection with conducting clinical trials and preclinical studies. The financial terms of these contracts are subject to negotiations which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects clinical trial and preclinical study expenses in the financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the clinical trial or preclinical study as measured by the timing of various aspects of the clinical trial, preclinical study, or related activities. The Company determines accrual estimates through review of the underlying contracts along with preparation of financial models taking into account correspondence with clinical and other key personnel and third-party service providers as to the progress of the clinical trials, preclinical studies, or other services being conducted. During the course of a clinical trial or preclinical study, the Company adjusts the rate of expense recognition if actual results differ from estimates. Public and Private Placement Warrants Upon completion of the Business Combination, the Company assumed public and private placement warrants that were issued by LWAC in connection with their IPO in January 2021 whereby holders of the public and private placement warrants are entitled to acquire common stock of the Company. The Company has concluded that the public warrants are equity-classified. Since the settlement value of the private placement warrants is dependent, in part, on who holds the warrants at the time of settlement, they are not considered indexed to the Company's stock and are therefore recorded as liabilities. Warrants classified as liabilities are recorded at their estimated fair value on the date of issuance and are revalued at each subsequent balance sheet date, with fair value changes recognized in other income (expense), net in the accompanying statements of operations and comprehensive income (loss). The Company estimates the fair value of these warrants using the Black-Scholes option pricing model. Stock-Based Compensation Expense Stock-based compensation expense represents the cost of the grant date fair value of employee stock option grants recognized over the requisite service period of the awards (usually the vesting period) on a straight- line basis. The Company estimates the fair value of stock option grants using the Black-Scholes option-pricing model. The Company accounts for stock options granted to non-employees using the fair value approach. The Black-Scholes option-pricing model requires the use of subjective assumptions, including the risk- free interest rate, the expected stock price volatility, the expected term of stock options, and the expected dividend yield. The fair value of the underlying common stock used within the Black-Scholes option-pricing model is based on the closing price of common stock on the date of grant. Earn-out Shares In accordance with the Merger Agreement, 5,000,000 shares are contingently issuable to Old eFFECTOR stockholders and option holders upon the occurrence of the Triggering Event, defined within the Merger Agreement as the date on which the common stock price equals or exceeds $ 20.00 over at least 20 trading days out of 30 consecutive trading day period for the two-year period following the close date of the Business Combination. The estimated fair value of the Earn-Out Shares was determined using a Monte Carlo simulation valuation model using a distribution of potential outcomes on a monthly basis over the earn-out period using the most reliable information available. The Company has determined that the contingent obligation to issue Earn-Out Shares to existing Old eFFECTOR shareholders is not indexed to the Company's stock under ASC 815-40 and therefore equity treatment is precluded. The Triggering Event that determines the issuance of the Earn-Out Shares includes terms that are not solely indexed to our common stock , and as such liability classification is required. Equity-linked instruments classified as liabilities are recorded at their estimated fair value on the date of issuance and are revalued at each subsequent balance sheet date, with fair value changes recognized in other income (expense), net in the accompanying statements of operations and comprehensive income (loss). The Company has determined that the contingent obligation to issue Earn-Out Shares to existing Old eFFECTOR option holders falls within the scope of ASC 718, Share-based Compensation, because the option holders are required to continue providing service until the occurrence of the Triggering Event. The fair value of the option holder Earn-Out Shares is recorded as share-based compensation over the derived service period of the Monte Carlo simulation valuation model, recognized in research and development and general and administrative expense in the accompanying statements of operations and comprehensive income (loss). Recent Accounting Guidance From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board ("FASB") or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes, based on their preliminary assessment, that the impact of recently issued standards that are not yet effective will not have a material impact on their financial position or results of operations upon adoption. Net Income (Loss) Per Share The Company computes net income (loss) per share in accordance with the FASB guidance for Earnings Per Share, which established standards regarding the computation of earnings per share by companies that have issued securities other than common stock that contractually entitle the holder to participate in earnings and dividends. The guidance requires earnings available to common shareholders for the period, after deduction of preferred stock preferences, to be allocated between the common and preferred shareholders based on their respective rights to receive dividends. The Company is not required to present basic and diluted net income per share for securities other than common stock; therefore, the net income (loss) per share amounts only pertain to the Company’s common stock. Basic net income (loss) per share is calculated by dividing income (loss) allocable to common shareholders (net income after reduction for any required returns to preferred stock shareholders prior to paying dividends to the common shareholders, assuming current income for the period had been distributed) by the weighted-average number of common shares outstanding, during the period. The Company calculates diluted net income per share using the more dilutive of the 1) treasury stock method, if-converted method, or contingently issuable share method, as applicable, or 2) the two-class method. The Company has used the treasury stock method to calculate diluted net income (loss) per share for the nine months ended September 30, 2021, as the Company was in a net loss position, and used the two-class method for the three months ended September 30, 2021 and the three and nine months ended September 30, 2020, as the if-converted method is anti-dilutive. Diluted net income per share for the three months ended September 30, 2021 and the three and nine months ended September 30, 2020 also reflects the assumed exercise of options outstanding during the period using the treasury stock method, to the extent dilutive. Warrants were excluded from the calculation of diluted net income per share for the three and nine months ended September 30, 2020 as their effect would be anti-dilutive. As a result of the Business Combination, the Company has retroactively restated the weighted average shares outstanding prior to August 25, 2021, to give effect to the Exchange Ratio. The following table sets forth the computation of basic and diluted net income (loss) per share (in thousands, except share and per share data): Three Months Ended Nine Months Ended September 30, September 30, September 30, September 30, Basic Net Income (Loss) per share Net income (loss) $ 8,879 $ ( 7,609 ) $ ( 3,251 ) $ 20,065 Less: income allocated to participating securities — — — ( 19,502 ) Net income (loss) attributable to common shareholders $ 8,879 $ ( 7,609 ) $ ( 3,251 ) $ 563 Weighted average common shares outstanding - basic 16,701,967 1,438,584 6,588,282 1,398,954 Net income (loss) per share - basic $ 0.53 $ ( 5.29 ) $ ( 0.49 ) $ 0.40 Diluted Net Income (Loss) per share Net income (loss) $ 8,879 $ ( 7,609 ) $ ( 3,251 ) $ 20,065 Less: gain on change in fair value of private placement warrants ( 367 ) — — — Less: income allocated to participating securities — — — ( 19,093 ) Net income (loss) attributable to common shareholders $ 8,512 $ ( 7,609 ) $ ( 3,251 ) $ 972 Weighted average common shares outstanding - basic 16,701,967 1,438,584 6,588,282 1,398,954 Weighted average effect of dilutive securities: Stock options 3,302,088 — — 1,106,286 Private placement warrants 1,923 — — — Public warrants 61,737 — — — Weighted average common shares outstanding - diluted 20,067,715 1,438,584 6,588,282 2,505,240 Net income (loss) per share - diluted $ 0.42 $ ( 5.29 ) $ ( 0.49 ) $ 0.39 Potentially dilutive securities as of September 30, 2021 and 2020 are as follows (in common stock equivalent shares): For the Three Months Ended September 30, For the Nine Months Ended September 30, 2021 2020 2021 2020 Series A Convertible Preferred Stock — 11,563,819 — 11,563,819 Series B Convertible Preferred Stock — 10,154,819 — 10,154,819 Series C Convertible Preferred Stock — 6,734,590 — 6,734,590 Series C Convertible Preferred Stock Warrants 108,029 70,455 108,029 70,455 Public warrants — — 5,833,333 — Private placement warrants — — 181,667 — Earn-Out Shares 5,000,000 — 5,000,000 — Unvested sponsor shares 300,000 — 300,000 — Stock options outstanding 64,486 3,630,273 3,978,805 523,893 Total 5,472,515 32,153,956 15,401,834 29,047,576

Business Combination

Business Combination	9 Months Ended
	Sep. 30, 2021
Business Combinations [Abstract]
Business Combination	3. Business Combination As discussed in Note 1, on August 25, 2021, the Company completed the previously announced Business Combination pursuant to the Merger Agreement. Upon closing of the Business Combination, the combined company was renamed eFFECTOR Therapeutics, Inc. As a result of the Business Combination, each share of Old eFFECTOR preferred stock and common stock was converted into the right to receive approximately 0.09657 shares of the Company's common stock (the “Common Stock”) for an aggregate of 30,021,762 shares of common stock issued in the Business Combination. Former holders of shares of Old eFFECTOR common stock (including shares received as a result of the conversion of Old eFFECTOR preferred stock and the exercise of Old eFFECTOR warrants) and former holders of options to purchase shares of Old eFFECTOR will also be entitled to receive their pro rata share of up to 5,000,000 earn-out shares (the "Earn-Out Shares") of Common Stock if, on or prior to August 26, 2023, the closing share price of shares of common stock equals or exceeds $ 20.00 over at least 20 trading days within a 30 -day trading period (the “Triggering Event”) and, in respect of each former holder of Old eFFECTOR stock options, such holder continues to provide services to the Company or one of its subsidiaries at the time of such Triggering Event. The Earn-Out Shares will also be earned and issuable in the event of a change in control of the Company on or prior to August 26, 2023 that results in the holders of common stock receiving a per-share price equal to or in excess of $20.00. Pursuant to subscription agreements entered into in connection with the Merger Agreement (collectively, the “Subscription Agreements”), certain investors agreed to subscribe for an aggregate of 6,070,003 newly-issued shares of Common Stock at a purchase price of $ 10.00 per share for an aggregate purchase price of $ 60.7 million (the “PIPE Financing”). At the closing, we consummated the PIPE Financing. A total of 10,347,611 shares of common stock were issued in connection with the close of the Business Combination, inclusive of the PIPE Financing shares and shares held by LWAC sponsor and public investors. In connection with the closing of the Business Combination, the LWAC sponsor received 4,056,250 shares of eFFECTOR common stock, of which 300,000 shares were subject to vesting if, on or prior to August 25, 2024, the price of shares of common stock equals or exceeds $ 15.00 per share for a period of at least 20 trading days out of 30 consecutive trading days ending on the trading day immediately prior to the date of determination (the "Sponsor Shares"). The 300,000 sponsor shares subject to vesting meet the criteria for equity classification, but are not considered outstanding from an accounting perspective. These shares are considered issued but not outstanding as of September 30, 2021 and have been excluded from outstanding shares in the calculation of income (loss) per share for the three and nine months ended September 30, 2021. After giving effect to the Business Combination, and the consummation of the PIPE Financing, there were 40,669,373 shares of Common Stock issued and 40,369,373 shares of Common Stock issued and outstanding. In connection with the closing of the Business Combination, options to purchase shares of Old eFFECTOR common stock were converted, at an exchange ratio of approximately 0.09657 , into options to purchase an aggregate of 3,920,657 shares of Common Stock, with a weighted-average exercise price of $ 1.56 per share. Pursuant to the terms of the Merger Agreement, the Company’s shareholders exchanged their interests in the Company for shares of common stock of eFFECTOR. In addition, awards under the Company’s existing equity incentive plans, including the 2013 Plan, continue in full force and effect on the same terms and conditions as were previously applicable to such awards, subject to adjustments to the exercise price and number of shares of common stock issuable upon exercise based on the final exchange ratio of approximately 0.09657 . Gross proceeds from this transaction totaled approximately $ 67.0 million, which included funds held in LWAC’s trust and operating accounts and the completion of a concurrent sale of 6,070,003 shares of Common Stock at a purchase price of $ 10.00 per share in the PIPE Financing. The transaction was accounted for as a “reverse recapitalization” in accordance with US GAAP. Under the reverse recapitalization model, the business combination was treated as eFFECTOR issuing equity for the net assets of LWAC, with no goodwill or intangible assets recorded. Under this method of accounting, LWAC was treated as the “acquired” company for financial reporting purposes. This determination is primarily based on the fact that subsequent to the business combination, eFFECTOR stockholders have a majority of the voting power of the combined company, comprise all of the ongoing operations of the combined entity, comprise a majority of the governing body of the combined company, and eFFECTOR senior management comprise all of the senior management of the combined company. All periods prior to the Business Combination have been retroactively adjusted using the Exchange Ratio for the equivalent number of shares outstanding immediately after the Business Combination to effect the reverse recapitalization. In connection with the Business Combination, the Company raised $ 52.9 million of net proceeds. This amount was comprised of $ 6.3 million of cash held in LWAC’s trust and operating accounts from its initial public offering and $ 60.7 million of cash in connection with the PIPE Financing, LWAC’s transaction costs and underwriters’ fees of $ 11.1 million. Old eFFECTOR incurred $ 3.0 million of transaction costs, consisting of banking, legal, and other professional fees which were recorded as a reduction to additional paid-in capital. In addition to the net proceeds disclosed above, the Company also assumed $ 0.9 million of net liabilities of LWAC upon closing of the Business Combination. The following summarizes the common stock outstanding following the consummation of the Business Combination, PIPE Financing and the automatic cashless exercise of Old eFFECTOR warrants: Shares % Old eFFECTOR Stockholders 30,021,762 74.4 % LWAC Stockholders 521,358 1.3 % LWAC Founders (1) 3,756,250 9.3 % PIPE Investors 6,070,003 15.0 % Total 40,369,373 100.0 % (1) Excludes 300,000 Sponsor Shares subject to vesting that are not considered outstanding from an accounting perspective.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: 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 for similar assets and liabilities in active markets, 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 liability. 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 Company’s cash equivalents are classified using Level 1 inputs within the fair value hierarchy because they are valued using quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented. The Company estimates the fair value of preferred stock warrants at the time of issuance and subsequent remeasurement using the Black-Scholes option pricing model at each reporting date, if required, based on the following inputs: the risk-free interest rates; the expected dividend rates; the remaining contractual life of the warrants; the fair value of the underlying stock; and the expected volatility of the price of the underlying stock. The estimates are based, in part, on subjective assumptions and could differ materially in the future. Changes to these assumptions as well as the fair value of the Company’s stock on the reporting date can have a significant impact on the fair value of the warrant liability. The following table summarizes the Company’s assets and liabilities that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy as of September 30, 2021 and December 31, 2020 (in thousands): Fair Value Measurements Using September 30, Quoted Prices Significant Significant 2021 Level 1 Level 2 Level 3 Assets Money market funds $ 54,768 $ 54,768 $ — $ — Total assets $ 54,768 $ 54,768 $ — $ — Liabilities Private placement warrant liability $ 1,495 $ — $ — $ 1,495 Earn-out liability 43,250 — — 43,250 Total liabilities $ 44,745 $ — $ — $ 44,745 Fair Value Measurements Using December 31, Quoted Prices Significant Significant 2020 Level 1 Level 2 Level 3 Assets Money market funds $ 15,216 $ 15,216 $ — $ — Total assets $ 15,216 $ 15,216 $ — $ — Liabilities Preferred stock warrant liability $ 433 $ — $ — $ 433 Total liabilities $ 433 $ — $ — $ 433 The preferred stock warranty liability is measured at fair value, using a combination of observable and unobservable inputs. The change in fair value of the preferred stock warrant liability is recorded in Other income (expense) on the statement of operations and comprehensive income (loss). All outstanding preferred stock warrants were cashless exercised as a result of the Business Combination on August 25, 2021 (See Note 8). The preferred stock warrants were remeasured to fair value on the date of cashless exercise based on the net shares issued and fair value of common stock on the settlement date, which was the close date of the Business Combination on August 25, 2021. The following key assumptions were used in determining the fair value of the preferred stock warrant liability valued using the Black-Scholes option pricing model as of December 31, 2020: December 31, Fair value of Series C convertible preferred stock $ 0.70 Expected volatility 96.3 % Risk-free interest rate 0.7 % Expected term (in years) 7.7 Expected dividend yield — The following table presents activity for the preferred stock warrant liability measured at fair value using significant unobservable Level 3 inputs during the nine months ended September 30, 2021 and 2020 (in thousands): Series C Preferred Stock Warrant Liability Balance at December 31, 2019 $ 442 Change in fair value 68 Balance at September 30, 2020 $ 510 Balance at December 31, 2020 $ 433 Issuance of new warrants 271 Change in fair value 153 Warrant exercises ( 857 ) Balance at September 30, 2021 $ — In connection with the Business Combination, the Company assumed the public and private placement warrants described in Note 2. The private placement warrants are precluded from equity treatment and are recorded as liabilities as they are not considered indexed to the Company's Common Stock. The private placement warrant liability is measured at fair value, using a combination of observable and unobservable inputs. The change in fair value of the private placement warrant liability is recorded in other income (expense) on the statement of operations and comprehensive income (loss). The following key assumptions were used in determining the fair value of the private placement warrant liability valued using the Black-Scholes option pricing model as of September 30, 2021 and August 25, 2021: September 30, As of August 25, 2021 at Initial Measurement Common stock price $ 14.05 $ 16.98 Expected volatility 65.0 % 60.0 % Risk-free interest rate 1.0 % 0.8 % Expected term (in years) 4.9 5.0 Expected dividend yield — — The following table presents activity for the private placement warrant liability measured at fair value using significant unobservable Level 3 inputs during the nine months ended September 30, 2021 (in thousands): Private Placement Warrant Liability Private Placement Warrants liability - August 25, 2021 (closing date) $ 1,862 Change in fair value - Closing Date through September 30, 2021 ( 367 ) Balance at September 30, 2021 $ 1,495 Former holders of shares of Old eFFECTOR common stock were allocated Earn-Out shares in connection with the completion of the Business Combination with LWAC which are accounted for as liabilities. Please refer to Note 10 for additional details surrounding the valuation methodology for these Earn-Out shares.

Property and Equipment , net

Property and Equipment , net	9 Months Ended
	Sep. 30, 2021
Property Plant And Equipment [Abstract]
Property and Equipment , net	5. Property and Equipment, net Property and equipment, net consists of the following (in thousands): September 30, December 31, Lab equipment $ 30 $ 30 Computer and office equipment 124 133 Furniture and fixtures 64 64 Construction in process 2 — 220 227 Less accumulated depreciation and amortization ( 199 ) ( 193 ) $ 21 $ 34 The Company recorded depreciation and amortization expense of approximately $ 6 thousand and $ 40 thousand for the three months ended September 30, 2021 and 2020 , respectively, and recorded approximately $ 20 thousand and $ 127 thousand for the nine months ended September 30, 2021 and 2020, respectively.

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2021
Payables And Accruals [Abstract]
Accrued Expenses	6. Accrued Expenses Accrued expenses consist of the following (in thousands): September 30, December 31, Employee compensation $ 803 $ 230 Research and development 702 755 Professional and outside services 760 44 Interest 128 598 Income taxes payable 351 351 Other 4 6 $ 2,748 $ 1,984

Term Loans

Term Loans	9 Months Ended
	Sep. 30, 2021
Longterm Notes And Loans By Type Current And Noncurrent [Abstract]
Term Loans	7. Term Loans SVB Term Loans In August 2018, Old eFFECTOR entered into a Loan and Security Agreement (“LSA”) with Silicon Valley Bank (“SVB”), pursuant to which the Company may borrow up to $ 20.0 million, issuable in three separate tranches of $ 7.5 million (“Term Loan A”), $ 7.5 million (“Term Loan B”) and $ 5.0 million (“Term Loan C”), collectively referred to as the Term Loans. The Term Loan A became available to the Company at the effective date of the LSA on August 31, 2018 and the Company borrowed the $ 7.5 million under the Term Loan A on that date, receiving the cash proceeds on September 5, 2018. Term Loan B was immediately available commencing on the effective date of the LSA and ending on the earlier of 1) August 31, 2019, and 2) the occurrence of an event of default. The Company borrowed the $ 7.5 million under Term Loan B on November 19, 2018. Term Loan C was not drawn. The Term Loans had an interest-only period that commenced upon the borrowing of each tranche of the Term Loans with interest due and payable upon the first day of each month. The interest-only period ended August 31, 2020. The Company was required to make a final payment equal to 5.5 % of the original aggregate principal amount of the Term Loans at maturity, which was accrued over the term of the debt arrangements. The Term Loans had a maturity date of February 1, 2023 . In connection with the LSA, the Company issued two separate warrants, each to purchase up to 46,970 shares of Series C Preferred Stock at an exercise price of $ 5.33 per share, to SVB and Life Science Loans II, LLC (life science loan sector of SVB). The number of shares subject to each warrant as of December 31, 2020, was 35,227 in connection with the Term Loan A and Term Loan B. Each warrant was automatically exercised on a cashless basis on August 25, 2021, in connection with the completion of the Business Combination, for 16,477 shares of Common Stock. The Term Loans carried an interest rate equal to the greater of 1.5 % plus prime or 6.5 %, with an effective interest rate at December 31, 2020, of 9.1 % and 9.0 % for Term Loan A and Term Loan B, respectively. The Company recorded a debt discount of $ 0.2 million for the estimated fair value of warrants and debt issuance costs upon the borrowing of each Term Loan A and Term Loan B, which was being amortized to interest expense over the term of the loan using the effective-interest method. As of December 31, 2020, the Company had $ 13.0 million of outstanding principal under the Term Loans of which $ 12.9 million is reflected on the balance sheet net of debt discounts. Interest expense, including amortization of debt discount related to the SVB Term Loans, totaled zero and $ 0.3 million for the three months ended September 30, 2021 and 2020, respectively, and $ 0.2 million and $ 1.0 million for the nine months ended September 30, 2021 and 2020, respectively. In March 2021, Old eFFECTOR repaid the SVB Term Loans using the proceeds from Oxford Term A Loans (defined below). The aggregate outstanding principal balance of SVB Term Loans A and B was $ 11.5 million at the date of repayment. The Company paid the entire outstanding principal balance, along with a final payment in the amount of $ 0.8 million (equal to 5.5% of the original aggregate principal amount), a prepayment fee of $ 0.1 million (equal to 1 % of the original aggregate principal amount), and $ 37,000 of accrued interest. The Company recorded a loss on debt extinguishment in the amount of $ 0.5 million in connection with the transaction, which has been recorded in Loss on debt extinguishment on the Statement of Operations for the period. The loss on debt extinguishment includes the unamortized debt discount and final payment associated with Term Loan A and Term Loan B at the time of extinguishment along with the $ 0.1 million prepayment fee. Oxford Term Loans In March 2021, Old eFFECTOR entered into a Loan and Security Agreement (“Oxford LSA”) with Oxford Finance LLC (“Oxford”), pursuant to which the Company may borrow up to $ 30.0 million, issuable in two separate tranches of $ 20.0 million (“Term A Loans”) and $ 10.0 million (“Term B Loans”), collectively referred to as the Oxford Loans. The Term A Loans became available to the Company at the effective date of the Oxford LSA on March 19, 2021 and $ 12.5 million of the proceeds were used to pay off the outstanding SVB Term Loans. The remaining net proceeds from Term A Loans of $ 7.4 million, after taking into effect specified issuance and legal fees designated within the distribution letter, were distributed to the Company in March 2021. Term B Loans will only become available to the Company upon achievement of certain clinical development milestones (“Phase II Milestones”) and is available until the earlier of (i) May 31, 2022 , (ii) forty-five days after the occurrence of the Phase II Milestones, and (iii) the occurrence of an event of default. The Term A Loans have an interest-only period that commences upon the borrowing with interest due and payable upon the first day of each month. The interest-only period ends May 1, 2023 , provided that upon the funding of the Term B Loans the end date will be extended to May 1, 2024 . The Company is required to make a final payment equal to 5.5 % of each funded tranche at maturity, which has been recorded as a debt discount for the Term A Loan which is outstanding and is being amortized over the term of the debt arrangements. The Oxford Loans have a maturity date of March 18, 2026 . In connection with the Oxford LSA, the Company issued warrants to purchase a total of 37,575 shares of Series C Preferred Stock at an exercise price of $ 5.33 per share. The warrants were automatically exercised on a cash basis on August 25, 2021, in connection with the completion of the Business Combination, for 17,575 shares of Common Stock. The Oxford Loans carry a variable interest rate equal to the greater of (i) 7.7 % and (ii) the sum of the prime rate plus 4.45 %. The Company has the option to prepay all, but not less than all, of the borrowed amounts, provided that the Company will be obligated to pay a prepayment fee equal to (i) 3.0 % of the outstanding principal balance of the applicable Oxford Loans if prepayment is made prior to the first anniversary of the effective date of the Oxford LSA, (ii) 2.0 % of the outstanding principal balance of the applicable Oxford Loans if prepayment is made after the first anniversary of the effective date of the Oxford LSA but before the second anniversary, and (iii) 1.0 % of the outstanding principal balance of the applicable Oxford Loans if prepayment is made after the second anniversary of the effective date of the Oxford LSA but before the third anniversary. No prepayment fee will apply for a prepayment made after the third anniversary of the effective date of the Oxford LSA and prior to the maturity date. The Company’s obligations under the Oxford LSA are secured by a first priority security interest in substantially all of its current and future assets, other than its owned intellectual property. The Company is also obligated to comply with various other customary covenants, including restrictions on its ability to encumber intellectual property assets without consent. The Company recorded a debt discount of $ 1.5 million for the estimated fair value of warrants, debt issuance costs upon the borrowing of Term A Loans, and final payment to be made, which is being amortized to interest expense over the term of the loan using the effective-interest method. As of September 30, 2021 , the Company had $ 20.0 million of outstanding principal under the Term A Loans of which $ 18.7 million is reflected on the balance sheet net of debt discounts. Interest expense, including amortization of debt discount related to the Oxford Term A Loans, totaled $ 0.5 million and $ 1.0 million for the three and nine months ended September 30, 2021. The Company is in compliance with all covenants under the Oxford LSA as of September 30, 2021. The Term A Loans include customary events of default, including instances of a material adverse change in our operations, that may require prepayment of the outstanding Term A Loans. There have been no events of default as of the date of issuance of these financial statements. Based on the outstanding principal amounts for the Company’s Term A Loans, the following table sets forth by year the Company’s required future principal payments as of September 30, 2021 (in thousands): As of September 30, 2021 2023 $ 4,444 2024 6,667 2025 6,667 2026 2,222 Required future principal payments $ 20,000 Unamortized debt discount ( 1,337 ) Non-current term loans, net as of September 30, 2021 $ 18,663

Warrants

Warrants	9 Months Ended
	Sep. 30, 2021
Warrants and Rights Note Disclosure [Abstract]
Warrants	8. Warrants Preferred Stock Warrants The Company accounts for its warrants to purchase shares of convertible preferred stock as a liability. The Company adjusted the liability for changes in fair value of these warrants up until the closing date of the Business Combination. Upon consummation of the Business Combination on August 25, 2021, the outstanding warrants were cashless exercised and 50,529 total net shares were issued, after giving effect to the application of the exchange ratio of approximately 0.09657 . The following table summarizes the outstanding warrants to purchase shares of preferred stock and the corresponding exercise price as of September 30, 2021 and December 31, 2020: September 30, December 31, Exercise Price Expiration Date Series C preferred stock warrants — 70,455 $ 5.33 August 31, 2028 Series C preferred stock warrants — — $ 5.33 March 19, 2031 Assumed Public Warrants and Private Placement Warrants Following the consummation of the Business Combination, holders of the public warrants and private placement warrants are entitled to acquire common stock of the Company. The warrants will become exercisable on January 7, 2022, which is 12 months from the closing of the LWAC's initial public offering. Each whole warrant entitles the registered holder to purchase one share of Common Stock at an exercise price of $ 11.50 per share, beginning 30 days after the closing date of the Business Combination. The public warrants and private placement warrants will expire five years after the completion of the Business Combination. Once the public warrants and private placement warrants became exercisable, the Company has the right to redeem the outstanding warrants in whole and not in part at a price of $ 0.01 per warrant upon a minimum of 30 days’ prior written notice of redemption, if and only if the last sale price of the Common Stock equals or exceeds $ 18.00 per share for any 20 trading days within a 30 -trading day period ending on the third trading day prior to the date on which the Company sends the notice of redemption to the warrant holders. The private placement warrants are identical to the public warrants except that, so long as they are held by the Sponsor or its permitted transferees: (i) they will not be redeemable by the Company; (ii) they may be exercised by the holders on a cashless basis; and (iii) they are subject to registration rights. Private placement warrants are liability-classified (See Note 4) and the public warrants are equity-classified. The following table summarizes the number of outstanding public warrants and private placement warrants and the corresponding exercise price as of September 30, 2021 and December 31, 2020: September 30, December 31, Exercise Price Expiration Date Public warrants 5,833,333 — $ 11.50 August 24, 2026 Private placement warrants 181,667 — $ 11.50 August 24, 2026

Preferred Stock and Stockholder

Preferred Stock and Stockholders' Deficit	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Preferred Stock and Stockholders' Deficit	9. Preferred Stock and Stockholders’ Deficit Preferred Stock Upon closing of the Business Combination transaction, pursuant to the terms of the Amended and Restated Certificate of Incorporation, the Company authorized 100,000,000 shares of preferred stock with a par value $ 0.0001 per share. eFFECTOR's board of directors has the authority, without further action by the stockholders to issue such shares of preferred stock in one or more series, to establish from time to time the number of shares to be included in each such series, and to fix the dividend, voting, and other rights, preferences and privileges of the shares. There were no issued and outstanding shares of preferred stock as of September 30, 2021. In connection with the closing of the Business Combination on August 25, 2021, all Old eFFECTOR convertible preferred stock was converted into Common Stock of eFFECTOR at an Exchange Ratio of 0.09657 . 28,453,228 total shares of Old eFFECTOR convertible preferred stock (as adjusted for the exchange ratio), composed of 11,563,819 shares of Old eFFECTOR Series A convertible preferred stock, 10,154,819 shares of Old eFFECTOR Series B convertible preferred stock, and 6,734,590 shares of Old eFFECTOR Series C convertible preferred stock, were converted into 28,453,228 shares of eFFECTOR Common Stock. The authorized shares, purchase price, number of shares and liquidation amount for each series of convertible preferred stock as of December 31, 2020, as adjusted for the Exchange Ratio, is as follows (in thousands, except share and per share amounts): Shares Purchase Shares Liquidation Convertible preferred stock: Series A 14,056,840 $ 4.05382 11,563,819 $ 46,878 Series B 11,071,448 $ 5.05806 10,154,819 $ 51,364 Series C 7,346,140 $ 5.32253 6,734,590 $ 35,845 Total 32,474,428 28,453,228 $ 134,087 Common Stock During the three and nine months ended September 30, 2021 , the Company issued 57,489 and 72,940 shares of common stock in connection with the exercise of stock options, for net cash proceeds of $ 63,000 and $ 78,000 , respectively. During the three and nine months ended September 30, 2020 , the Company issued 16,899 and 111,354 of shares of common stock in connection with the exercise of stock options, for net cash proceeds of $ 20,000 and $ 108,000 , respectively. 2013 Equity Incentive Plan Prior to the Business Combination, Old eFFECTOR maintained its 2013 Equity Incentive Plan (the “2013 Plan”), under which Old eFFECTOR granted incentive stock options, restricted stock awards, and other stock-based awards to employees, directors, and non-employee consultants. Upon the closing, the Company ceased granting awards under the 2013 Plan and, as described below, all awards under the 2013 Plan were converted into awards under the 2021 Plan with the same terms and conditions. As of August 25, 2021, prior to the Business Combination transaction, 3,920,657 Old eFFECTOR options remained outstanding under the 2013 Plan, as adjusted for the application of the Exchange Ratio. Conversion of Awards In connection with the Business Combination, each option of Old eFFECTOR that was outstanding and unexercised immediately prior to the close date (whether vested or unvested) was converted into an option to acquire an adjusted number of shares of eFFECTOR common stock at an adjusted exercise price per share (the "Substitute Options"), based on the Exchange Ratio of approximately 0.09657 , and will continue to be governed by substantially the same terms and conditions, including vesting, as were applicable to the former option. Each Substitute Option will be exercisable for a number of whole shares of Common Stock equal to the product of the number of shares of Old eFFECTOR common stock underlying such Old eFFECTOR option multiplied by the Exchange Ratio, and the per share exercise price of such Substitute Option will be equal to the quotient determined by dividing the exercise price per share of Old eFFECTOR common stock by the Exchange Ratio. In connection with the closing, 40,599,270 options to purchase shares of Old eFFECTOR common stock were exchanged for options to purchase an aggregate of 3,920,657 shares of Common Stock, with an as-adjusted weighted-average exercise price of $ 1.56 per share. 2021 Equity Incentive Plan and ESPP In connection with the consummation of the Business Combination on August 25, 2021, the Board of Directors approved the adoption of the 2021 Equity Incentive Plan (the “2021 Plan”). As of September 30, 2021, 6,506,338 shares of Common Stock are authorized for issuance pursuant to awards under the 2021 Plan, inclusive of any shares of Common Stock subject to stock options, restricted stock awards or other awards that were assumed in the Business Combination. As of September 30, 2021, 64,486 options to purchase common shares have been awarded and 6,441,852 shares remain available for issuance under the 2021 Plan. The 2021 Plan permits the granting of incentive stock options, restricted stock awards, other stock-based award or other cash-based awards to employees, directors, and non-employee consultants. At a special meeting of stockholders held on August 24, 2021, stockholders considered and approved the eFFECTOR Therapeutics, Inc. 2021 Employee Stock Purchase Plan (the "ESPP"). The ESPP provides for six-month offering periods, and at the end of each offering period, employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the last trading day of the offering period. An aggregate of 880,000 shares were initially reserved and available for issuance under the ESPP. The ESPP provides that the number of shares reserved and available for issuance under the plan will automatically increase each January 1, beginning on January 1, 2021, by 1.0% of the outstanding number of shares of common stock on the immediately preceding December 31, or such lesser amount as determined by our board of directors; provided that the total number of shares of common stock that become available for issuance under the ESPP will never exceed 15,000,000 . If our capital structure changes because of a stock dividend, stock split or similar event, the number of shares that can be issued under the ESPP will be appropriately adjusted. No awards were granted under the ESPP as of September 30, 2021. Stock Options In May 2013, the Company adopted the 2013 Equity Incentive Plan (the “2013 Plan”), which was amended in February 2016. The Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, stock appreciation rights, and stock bonuses to directors, employees and consultants of the Company. As of September 30, 2021 and December 31, 2020 , the number of shares reserved under the Plan was 3,914,319 an d 4,594,060 , r espectively. In August 2021, the Company adopted the 2021 Equity Incentive Plan (the “2021 Plan”). The Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, stock appreciation rights, and stock bonuses to directors, employees and consultants of the Company. As of September 30, 2021 and December 31, 2020 , the number of shares reserved under the 2021 Plan was 6,506,338 and zero , respectively. There were zero and 132,974 shares available for grant under the 2013 Plan as of September 30, 2021 and December 31, 2020 , respectively. In connection with the completion of the Business Combination and the adoption of the 2021 Plan, no further awards will be granted under the 2013 Plan. Options granted under the 2021 Plan are exercisable at various dates as determined upon grant and will expire no more than ten years from their date of grant, or in the case of certain non-statutory options, ten years from the date of grant. The exercise price of each option shall be determined by the Board of Directors based on the estimated fair value of the Company’s stock on the date of the option grant. In the case of incentive stock options, the exercise price shall not be less than 100 % of the fair market value of the Company’s common stock at the time the option is granted. For holders of more than 10 % of the Company’s total combined voting power of all classes of stock, incentive stock options may not be granted at less than 110 % of the fair market value of the Company’s stock at the date of grant and for a term not to exceed five years. Most option grants generally vest 25 % on the first anniversary of the original vesting commencement date, with the balance vesting monthly over the remaining three years . A summary of the Company’s stock option activity under the plans is as follows (in thousands, except share and per share amounts and years): Shares Weighted- Weighted- Aggregate Outstanding at December 31, 2020 3,887,038 $ 1.41 6.6 $ 3,806 Granted 204,512 10.28 9.8 Exercised ( 72,940 ) 1.06 4.5 Cancelled ( 39,805 ) 1.38 7.2 Outstanding at September 30, 2021 3,978,805 $ 1.87 6.1 $ 48,898 Vested and exercisable at September 30, 2021 2,912,657 $ 1.26 5.0 $ 37,248 For the nine months ended September 30, 2021 the total fair value of vested options was $ 0.5 million. The weighted-average grant date fair value of employee and non-employee option grants, on an as-converted basis based upon the Exchange Ratio, during the nine months ended September 30, 2021 was $ 7.18 per share. Stock-Based Compensation Expense The Company recognized stock-based compensation expense specifically related to stock options of $ 0.2 million and $ 0.6 million for the three and nine months ended September 30, 2021 , respectively, and recognized stock-based compensation expense specifically related to stock options of $ 0.2 million and $ 0.3 million for the three and nine months ended September 30, 2020 , respectively. The assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock option grants were as follows: Nine Months Ended September 30, 2021 2020 Risk-free interest rate 0.7 % - 0.9 % 0.3 % - 1.0 % Expected volatility 82 % - 90 % 87 % - 93 % Expected term (in years) 5.5 - 6.1 5.3 - 6.1 Expected dividend yield 0 % 0 % Risk-free interest rate. The risk-free rate assumption is based on the U.S. Treasury instruments, the terms of which were consistent with the expected term of the Company’s stock options. Expected volatility. Due to the Company’s limited operating history and lack of company-specific historical or implied volatility, the expected volatility assumption was determined by examining the historical volatilities of a group of industry peers whose share prices are publicly available. Expected term. The expected term of stock options represents the weighted-average period the stock options are expected to be outstanding. The Company uses the simplified method for estimating the expected term as provided by the SEC. The simplified method calculates the expected term as the weighted average of the time-to-vesting and the contractual life of the options. Expected dividend yield. The expected dividend assumption is based on the Company’s history and expectation of dividend payouts. The Company has not paid and does not intend to pay dividends. Forfeitures . The Company reduces stock-based compensation expense for actual forfeitures during the period in which they occur. As of September 30, 2021 , the unrecognized compensation cost related to outstanding employee options was $ 1.7 million and is expected to be recognized as expense over approximately 1.0 year. Unrecognized compensation cost related to outstanding nonemployee options was $ 0.8 million as of September 30, 2021 , and is expected to be recognized as expense over approximately 0.5 years. Common Stock Reserved for Future Issuance Common stock reserved for future issuance consists of the following as of September 30, 2021 and December 31, 2020: September 30, December 31, Convertible preferred stock — 28,453,228 Stock options issued and outstanding 3,978,805 3,887,038 Preferred stock warrants issued and outstanding — 70,455 Public warrants issued and outstanding 5,833,333 — Private placement warrants issued and outstanding 181,667 — Earn-Out shares 5,000,000 — Unvested sponsor shares 300,000 — Authorized for future stock awards or option grants 6,441,852 132,974 Total 21,735,657 32,543,695

Earn-out Shares

Earn-out Shares	9 Months Ended
	Sep. 30, 2021
Earn out Share [Abstract]
Earn-out Shares	10. Earn-Out Shares In accordance with the Merger Agreement, 5,000,000 shares are contingently issuable to Old eFFECTOR stockholders and option holders upon the occurrence of the Triggering Event, defined within the Merger Agreement as the date on which the common stock price equals or exceeds $ 20.00 over at least 20 trading days out of 30 consecutive trading day period for the two-year period following the close date of the Business Combination. As of August 25, 2021, the stockholders and option holders will be eligible to receive approximately 4,425,258 and 574,742 Earn-Out Shares, respectively, based on the fully diluted cap table of Old eFFECTOR. The fair value of the Earn-Out Shares is $ 13.79 per share as of the closing date of the Business Combination (August 25, 2021). As of September 30, 2021, the stockholders and option holders will be eligible to receive approximately 4,426,889 and 573,111 Earn-Out Shares, respectively, based on the current fully diluted cap table of Old eFFECTOR. The fair value of the Earn-Out Shares is $ 9.77 per share as of September 30, 2021. The estimated fair value of the Earn-Out Shares was determined using a Monte Carlo simulation valuation model using a distribution of potential outcomes on a monthly basis over the Earn-Out Period using the most reliable information available. Assumptions used in the valuation were as follows: September 30, As of August 25, 2021 at Initial Measurement Stock price $ 14.05 $ 16.98 Expected volatility 65.0 % 60.0 % Risk-free interest rate 0.3 % 0.2 % Forecast period (in years) 1.9 2.0 Cost of equity 20.0 % 20.0 % Old eFFECTOR Shareholders The Company has determined that the contingent obligation to issue Earn-Out Shares to existing Old eFFECTOR shareholders is not indexed to the Company's stock under ASC 815-40 and therefore equity treatment is precluded. The Triggering Event that determines the issuance of the Earn-Out Shares includes terms that are not solely indexed to the common stock of the Company, and as such liability classification is required. As of the consummation date of the Business Combination, the estimated fair value of the shareholder Earn-Out Shares was approximately $ 61.0 million and the Company will revalue the liability each reporting period with the changes in fair value being recorded to the Statements of Operations. For the three and nine months ended September 30, 2021 , there was a decrease in the earn-out liability of $ 17.8 million which was recorded as a gain on change in fair value within the Statements of Operations. In accordance with the Merger Agreement, Earn-Out Shares attributable to Old eFFECTOR option holders who discontinue providing service before the occurrence of the Triggering Event are reallocated to the remaining eligible stockholders and option holders. The earn-out liability is recorded on the balance sheet as a current liability since the expected date of achievement based on the valuation model is within the next twelve months. The following table presents activity for the Earn-Out liability measured at fair value using significant unobservable Level 3 inputs at the Merger close date (August 25, 2021) and September 30, 2021 (in thousands): Earn-out Liability Earn-out liability - August 25, 2021 (Closing Date) $ 61,024 Incremental shares due to option holder forfeitures 16 Change in fair value - Closing Date through September 30, 2021 ( 17,790 ) Balance at September 30, 2021 $ 43,250 Old eFFECTOR Option Holders The contingent obligation to issue Earn-Out Shares to existing Old eFFECTOR option holders falls within the scope of ASC 718, Share-based Compensation, because the option holders are required to continue providing service until the occurrence of the Triggering Event. The fair value of the option holder Earn-Out Shares at the Merger closing date (August 25, 2021) is approximately $ 7.9 million, which will be recorded as share-based compensation over the derived service period of 0.36 years following the consummation of the Business Combination. For the three and nine months ended September 30, 2021 , there was approximately $ 2.1 million recorded in share-based compensation related to the Earn-Out Shares, with approximately $ 5.8 million of unrecognized compensation expense as September 30, 2021 , which is expected to be recognized over the remaining derived service period of 0.27 years.

License Agreements

License Agreements	9 Months Ended
	Sep. 30, 2021
License Agreement Disclosure [Abstract]
License Agreement	11. License Agreements In May 2013, the Company entered into an agreement with the Regents of the University of California (“UCSF”) which provides the Company with an exclusive license to UCSF’s patent rights in certain inventions (the “UCSF Translational Profiling Patent Rights”) relating to translational profiling laboratory techniques initially developed at UCSF. Under the agreement, the Company is permitted to research, develop, make and sell products that it discovers and develops utilizing the UCSF Translational Profiling Patent Rights, which the Company refers to as licensed products, and use certain licensed processes utilizing the UCSF Translational Profiling Patent Rights and to sublicense such licensed products and processes. Under the agreements, the Company is required to use commercially reasonable efforts to meet certain specified development, regulatory and commercial milestones related to the licensed products within specified time periods. In consideration of the rights granted to the Company under the agreement, the Company made a one-time license issue fee cash payment to UCSF of $ 50,000 upon the issuance of the license in 2013. In July 2021, the Company entered into an amendment to the license agreement to confirm the impact of the Business Combination on the license agreement, including clarifying that in connection with the closing of the Business Combination, the Company would pay UCSF a one-time cash payment of approximately $ 1.0 million, subject to adjustment based on the final Exchange Ratio. The $ 1.0 million payment was made to UCSF in August 2021 in connection with the close of the Business Combination. The Company is also required to make cash milestone payments to UCSF upon the completion of certain clinical and regulatory milestones for the licensed products. The aggregate remaining potential milestone payments are approximately $ 375,000 . Additionally, the Company has agreed to pay UCSF a royalty of less than one percent on net sales of each of the first two licensed products sold by the Company or its affiliates, subject to minimum annual royalty payments and other adjustments in certain circumstances. The Company’s royalty obligations continue for each licensed product or service until the expiration of the last licensed patent covering the applicable licensed product or service. In the event the Company sublicenses any of the UCSF Translational Profiling Patent Rights, the Company has agreed to pay a percentage of sublicense revenue received at specified rates that start at low double digit percentages and decrease to single digit percentages based on the elapsed time from the effective date of the agreement. Additionally, the Company has agreed to pay a low double digit percentage of any payments it receives from the sales of a licensed product discovered or developed by the Company under a collaboration agreement and a low double digit percentage of any net sales with respect to a licensed service. UCSF may terminate the agreement if the Company fails to perform or violates any material term of the agreement and fails to cure such nonperformance or violation within 60 days of notice from UCSF or in the event of the Company’s insolvency. The Company is currently in compliance with all material terms of the agreement. The Company may terminate the agreement upon 60 days ’ written notice to UCSF and may terminate the UCSF Translational Profiling Patent Rights on a claim-by-claim, patent-by-patent and country-by-country basis by giving written notice to UCSF. Absent early termination, the agreement will continue until the expiration date of the longest-lived patent right included in the UCSF Translational Profiling Patent Rights. Any terminations initiated by the Company does not relieve their obligation to pay royalties and milestones under the terms of the UCSF agreement. In addition to the $ 1.0 million one-time cash payment made in connection with the completion of the Business Combination, the Company paid an annual minimum royalty of $ 15,000 to UCSF for the three and nine months ended September 30, 2021 and 2020 . All license related fees, including the one-time cash payment, were recorded as research and development expense.

Research Collaboration and Lice

Research Collaboration and License Agreement	9 Months Ended
	Sep. 30, 2021
Research And Development [Abstract]
Research Collaboration and License Agreement	12. Research Collaboration and License Agreement In December 2019, the Company entered into a Research Collaboration and License Agreement (the “Pfizer Agreement”) with Pfizer to research and develop small molecules that target eIF4E. Pursuant to the Pfizer Agreement, the Company granted Pfizer a worldwide, exclusive license, with a right to sublicense, under certain of the Company’s patents, know-how and materials, to use, develop, manufacture, commercialize, and otherwise exploit compounds or products targeting eIF4E, for any and all indications. Pursuant to the Pfizer Agreement, Pfizer granted the Company an option to co-fund and co-promote a single such licensed product under a profit and loss share arrangement in the United States. The option can be exercised prior to a specified time before the first patient is expected to be enrolled in a clinical trial intended to support an NDA for marketing approval. Under the Pfizer Agreement, the Company was responsible for initial research in collaboration with Pfizer, and Pfizer is responsible for all further development of the program, including submission of an IND and conducting all clinical development and commercialization activities. Pfizer is obligated to use commercially reasonable efforts to develop and seek regulatory approval for a licensed product, and commercialize a licensed product where Pfizer has received regulatory approval, in the United States and certain other countries. In the event the Company exercises its co-funding and co-promotion option, a joint steering committee will oversee the development plan and budget of the co-developed product, and the Company will have the responsibility to conduct a portion of product marketing presentations to healthcare providers. Pursuant to the Pfizer Agreement, the Company received an upfront, one-time, non-refundable, non-creditable payment of $ 15 million from Pfizer. Pfizer was obligated to reimburse the Company for costs incurred for research performed, up to a specified cap in the low double-digit millions. Upon the achievement of specified early development and regulatory milestones, Pfizer will be obligated to pay the Company up to $ 80 million in the aggregate. For other non-early stage development milestones Pfizer’s payment obligations to the Company depends upon whether the Company has exercised its co-funding and co-promotion option: 1) if it does not exercise the option, non-early stage development payments may total up to $ 165 million in aggregate, and 2) if it does exercise the option, non-early stage development payments may total up to $ 70 million in aggregate. Upon the achievement of specified sales milestones, Pfizer is also obligated to make tiered milestone payments of up to $ 235 million in aggregate. On a product-by-product basis, Pfizer will also be required to pay the Company high single-digit percentage royalties on annual net sales of each licensed product. If the Company exercises its co-promotion and co-funding option, royalty payments will exclude sales in the United States and the Company will share with Pfizer profits from sale of the relevant licensed product in the United States. Unless earlier terminated, the Pfizer Agreement will continue in effect until the expiration of all Pfizer payment obligations. Except in the United States, if the Company exercises its co-funding and co-promotion option, following expiration of the obligation to pay royalties for any licensed product in a given country and payment of all amounts due, Pfizer’s license to such licensed product in such country will become fully paid-up, perpetual, irrevocable and royalty-free. Pfizer may terminate the Pfizer Agreement for convenience upon written notice. Either party may terminate the Pfizer Agreement if an undisputed material breach by the other party is not cured within a defined period of time, or upon notice for insolvency-related events of the other party that are not discharged within a defined time period. Under the framework of ASC Topic 606, Revenue from Contracts with Customers, the Company identified two distinct performance obligations; 1) delivery of the license and 2) performance of future research activities specified within the research plan. The Company determined the standalone value of the license by calculating the present value of the probability weighted cash inflows to be generated from the Pfizer Agreement. These cash inflows include development and sales milestones and future royalties. The standalone value of the research activities was determined by identifying the market cost for services and supplies to perform such activities if it were to be outsourced to a third-party. The initial transaction price of $ 27.0 million was allocated to the two performance obligations on a relative standalone value basis, with $ 25.6 million allocated to the license and $ 1.4 million allocated to the research activities. The value attributable to the license was recognized upon delivery of the license to Pfizer and the value attributable to the research activities was recognized pro-rata based on the actual costs incurred by the Company compared to the total estimated costs of the research activities from the time of execution to the end of the research program. During the three and nine months ended September 30, 2020 , the Company received zero and $ 42.0 million from Pfizer in connection with the Research and License Agreement for delivery of the license, reimbursement of research activities specific within the research plan, and achievement of the first development milestones. For the three and nine months ended September 30, 2020, the Company recorded revenue of $ 0.6 million and $ 42.0 million, respectively. All of the revenue recorded for the three months ended September 30, 2020 related to the performance of research activities specified within the research plan. A contract liability balance of $ 42 thousand was recorded as of September 30, 2020. As of September 30, 2020, all future development and sales milestones (variable consideration) were fully constrained. There was no revenue recorded in connection with this agreement for the three and nine months ended September 30, 2021 because all development and sales milestones (variable consideration) were fully constrained.

DARPA Grant Revenue

DARPA Grant Revenue	9 Months Ended
	Sep. 30, 2021
DARPA Grant Revenue Disclosure [Abstract]
DARPA Grant Revenue	13. DARPA Grant Revenue In April 2021, the Company entered into a Research Subaward Agreement with UCSF, whereby up to $ 5.0 million in allowable costs are reimbursable for clinical and manufacturing activities related to zotatifin for the treatment of COVID-19 under the DARPA grant. Under the terms of Research Subaward Agreement, the Company is obligated to provide financial and technical reports to UCSF on a periodic basis. The subaward can be terminated by either party upon written notice and also in the event that DARPA suspends or terminates its award to UCSF. The Company recognized $ 0.4 million and $ 1.1 million of revenue under the DARPA grant in the three and nine months ended September 30, 2021 , respectively, and zero in the three and nine months ended September 30, 2020. As of September 30, 2021 and December 31, 2020 , the Company has a receivable of $ 0.2 million and zero recorded as a receivable within prepaid expenses and other current assets on the balance sheets, respectively.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	14. Commitments and Contingencies Leases The Company leased certain office and lab space in San Diego, California under a non-cancelable operating lease, which was amended in September 2019 to extend its terms through October 2020, with an option to renew for an additional two-year term. The portion of the lease associated with the office space was not extended and the Company vacated the space in October 2020. The portion of the lease associated with the lab space was extended until December 2020, at which time the Company vacated the space. In November 2020, the Company entered into a non-cancelable operating sublease for office space in San Diego, California, with a lease term through December 2021. Rents expense under these leases was $ 24,000 and $ 72,000 for the three and nine months ended September 30, 2021 , respectively, and $ 149,000 and $ 0.4 million for the three and nine months ended September 30, 2020, respectively. In September 2021, the Company entered a non-cancelable three-year lease for certain new office space in Solana Beach, California, with an option to renew for an additional three-year term. The initial term of the lease will start on November 1, 2021, and it will serve as the Company's new headquarters. The Company has not recorded any lease right-of-use asset or liability as of September 30, 2021, since possession of the property had not been obtained by that date. Annual rent payments are approximately $ 67,000 per year. During the three and nine months ended September 30, 2021 , the Company paid $ 28,000 and $ 84,000 , respectively, in lease payments, which were included in operating activities in the statements of cash flows. During the three and nine months ended September 30, 2020 , the Company paid $ 153,000 and $ 0.5 million, respectively, in lease payments, which were included in operating activities in the statements of cash flows. The following table summarizes supplemental balance sheet information related to leases as of September 30, 2021 and December 31, 2020. September 30, December 31, Assets: Operating lease right-of-use assets $ 24 $ 92 Total right-of-use assets 24 92 Liabilities Operating lease liabilities, current 28 108 Operating lease liabilities, non-current — — Total operating lease liabilities $ 28 $ 108 As of September 30, 2021, the future minimum annual lease payments under the existing operating leases were as follows (in thousands, except for weighted-average remaining lease term and weighted-average discount rate): In thousands (except for Weighted-average remaining lease term and Weighted-average discount rate) Remainder of 2021 $ 28 Total remaining lease payments 28 Less: imputed interest - Total operating lease liabilities 28 Less: current portion ( 28 ) Long-term operating lease liabilities $ - Weighted-average remaining lease term ( in years ) - Weighted-average discount rate 9 %

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	15. Income Taxes There was no provision for income taxes recorded during the three and nine months ended September 30, 2021 and tax expense of approximately $ 5 thousand and $ 0.4 million recorded in the three and nine months ended September 30, 2020 , respectively. The Company’s deferred tax assets continue to be fully offset by a valuation allowance.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements as of September 30, 2021 and for the three and nine months ended September 30, 2021 and 2020 have been prepared in accordance with U.S. generally accepted accounting principles (“US GAAP”) for interim financial information and pursuant to Article 10 of Regulation S-X of the Securities Act of 1933, as amended (the “Securities Act”). Accordingly, they do not include all of the information and notes required by US GAAP for complete financial statements. These unaudited financial statements include only normal and recurring adjustments that the Company believes are necessary to fairly state the Company’s financial position and the results of its operations and cash flows. The results for the three and nine months ended September 30, 2021 are not necessarily indicative of the results expected for the full fiscal year or any subsequent interim period. The balance sheet at December 31, 2020 has been derived from the audited financial statements at that date but does not include all the disclosures required by US GAAP for complete financial statements. Because all of the disclosures required by US GAAP for complete financial statements are not included herein, these unaudited financial statements and the notes accompanying them should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2020 included elsewhere in Form 424(b)(3) filed with the Securities and Exchange Commission (“SEC”) on October 5, 2021. The Business Combination was accounted for as a reverse recapitalization in accordance with U.S. GAAP. Under this method of accounting, LWAC was treated as the “acquired” Company and eFFECTOR is treated as the acquirer for financial reporting purposes. Accordingly, for accounting purposes, the Business Combination was treated as the equivalent of Old eFFECTOR issuing stock for the net assets of LWAC, accompanied by a recapitalization. The net assets of LWAC are stated at historical cost, with no goodwill or other intangible assets recorded. Old eFFECTOR was determined to be the accounting acquirer based on the following predominant factors:  Old eFFECTOR’s shareholders have a majority of the voting power of the combined company;  the Board and Management are primarily composed of individuals associated with Old eFFECTOR; and  Old eFFECTOR comprises all of the ongoing operations of the combined company. The consolidated assets, liabilities and results of operations prior to the Business Combination are those of Old eFFECTOR. The shares and corresponding capital amounts and income or losses per share, prior to the Business Combination, have been retroactively restated based on shares reflecting the Exchange Ratio established in the Business Combination.
Liquidity	Liquidity The Company has a limited operating history and the sales and income potential of the Company’s business and market are unproven. The accompanying financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or amounts and classification of liabilities that may result from the outcome of this uncertainty. Management is required to perform a two-step analysis over its ability to continue as a going concern. Management must first evaluate whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern (step 1). If management concludes that substantial doubt is raised, management is also required to consider whether its plans alleviate that doubt (step 2). The Company has experienced net losses and negative cash flows from operating activities since its inception, aside from the year ended December 31, 2020, as a result of non-recurring revenue in connection with the Research Collaboration and License Agreement with Pfizer which rendered net income in 2020. The Company has an accumulated deficit of $ 140.0 million at September 30, 2021. For the nine months ended September 30, 2021, the Company used $ 19.9 million in cash for operations. At September 30, 2021, the Company had cash and cash equivalents of $ 54.8 million. Management anticipates that its expenses will increase significantly in connection with its ongoing activities to support its research and development efforts, and it expects to incur substantial operating losses and negative cash flows from operations for the foreseeable future. The Company believes that its $ 54.8 million of cash and cash equivalents held as of September 30, 2021 are sufficient to fund planned operations for at least twelve months from the date that these financial statements are issued, though the Company may pursue additional cash resources through public or private equity or debt financings. Management’s expectations with respect to its ability to fund current planned operations is based on estimates that are subject to risks and uncertainties. Its operating plan may change as a result of many factors currently unknown to management and there can be no assurance that the current operating plan will be achieved in the time frame anticipated by the Company, and it may need to seek additional funds sooner than anticipated. If adequate funds are not available to the Company on a timely basis, management may be required to delay, limit, reduce or terminate certain of its research, product development or future commercialization efforts, obtain funds through arrangements with collaborators on terms unfavorable to the Company, or pursue merger or acquisition strategies, all of which could adversely affect the holdings or the rights of its stockholders.
Grant Revenue	Grant Revenue The Company’s grant revenues are derived from a grant with the Defense Advanced Research Projects Agency (“DARPA”) through the University of California, San Francisco (“UCSF”). The Company recognizes DARPA Grant revenue as reimbursable grant costs are incurred up to pre-approved award limits within the budget period. The costs associated with these reimbursements are reflected as a component of research and development expense in the accompanying statements of operations. Billings in excess of receipts are included as a receivable recorded within prepaid expenses and other current assets on the balance sheets.
Research and Development Costs	Research and Development Costs Research and development expenses primarily consist of costs associated with the preclinical and clinical development of the Company’s product candidates. Research and development costs are expensed as incurred.
Clinical Trial Accruals and Preclinical Studies	Clinical Trial Accruals and Preclinical Studies The Company is required to estimate expenses resulting from our obligations under contracts with vendors and consultants, CROs and clinical sites in connection with conducting clinical trials and preclinical studies. The financial terms of these contracts are subject to negotiations which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company reflects clinical trial and preclinical study expenses in the financial statements by matching those expenses with the period in which services and efforts are expended. The Company accounts for these expenses according to the progress of the clinical trial or preclinical study as measured by the timing of various aspects of the clinical trial, preclinical study, or related activities. The Company determines accrual estimates through review of the underlying contracts along with preparation of financial models taking into account correspondence with clinical and other key personnel and third-party service providers as to the progress of the clinical trials, preclinical studies, or other services being conducted. During the course of a clinical trial or preclinical study, the Company adjusts the rate of expense recognition if actual results differ from estimates.
Public and Private Placement Warrants	Public and Private Placement Warrants Upon completion of the Business Combination, the Company assumed public and private placement warrants that were issued by LWAC in connection with their IPO in January 2021 whereby holders of the public and private placement warrants are entitled to acquire common stock of the Company. The Company has concluded that the public warrants are equity-classified. Since the settlement value of the private placement warrants is dependent, in part, on who holds the warrants at the time of settlement, they are not considered indexed to the Company's stock and are therefore recorded as liabilities. Warrants classified as liabilities are recorded at their estimated fair value on the date of issuance and are revalued at each subsequent balance sheet date, with fair value changes recognized in other income (expense), net in the accompanying statements of operations and comprehensive income (loss). The Company estimates the fair value of these warrants using the Black-Scholes option pricing model.
Stock-Based Compensation Expense	Stock-Based Compensation Expense Stock-based compensation expense represents the cost of the grant date fair value of employee stock option grants recognized over the requisite service period of the awards (usually the vesting period) on a straight- line basis. The Company estimates the fair value of stock option grants using the Black-Scholes option-pricing model. The Company accounts for stock options granted to non-employees using the fair value approach. The Black-Scholes option-pricing model requires the use of subjective assumptions, including the risk- free interest rate, the expected stock price volatility, the expected term of stock options, and the expected dividend yield. The fair value of the underlying common stock used within the Black-Scholes option-pricing model is based on the closing price of common stock on the date of grant.
Earn-out Shares	Earn-out Shares In accordance with the Merger Agreement, 5,000,000 shares are contingently issuable to Old eFFECTOR stockholders and option holders upon the occurrence of the Triggering Event, defined within the Merger Agreement as the date on which the common stock price equals or exceeds $ 20.00 over at least 20 trading days out of 30 consecutive trading day period for the two-year period following the close date of the Business Combination. The estimated fair value of the Earn-Out Shares was determined using a Monte Carlo simulation valuation model using a distribution of potential outcomes on a monthly basis over the earn-out period using the most reliable information available. The Company has determined that the contingent obligation to issue Earn-Out Shares to existing Old eFFECTOR shareholders is not indexed to the Company's stock under ASC 815-40 and therefore equity treatment is precluded. The Triggering Event that determines the issuance of the Earn-Out Shares includes terms that are not solely indexed to our common stock , and as such liability classification is required. Equity-linked instruments classified as liabilities are recorded at their estimated fair value on the date of issuance and are revalued at each subsequent balance sheet date, with fair value changes recognized in other income (expense), net in the accompanying statements of operations and comprehensive income (loss). The Company has determined that the contingent obligation to issue Earn-Out Shares to existing Old eFFECTOR option holders falls within the scope of ASC 718, Share-based Compensation, because the option holders are required to continue providing service until the occurrence of the Triggering Event. The fair value of the option holder Earn-Out Shares is recorded as share-based compensation over the derived service period of the Monte Carlo simulation valuation model, recognized in research and development and general and administrative expense in the accompanying statements of operations and comprehensive income (loss).
Recent Accounting Guidance	Recent Accounting Guidance From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board ("FASB") or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes, based on their preliminary assessment, that the impact of recently issued standards that are not yet effective will not have a material impact on their financial position or results of operations upon adoption.
Net Income (Loss) Per Share	Net Income (Loss) Per Share The Company computes net income (loss) per share in accordance with the FASB guidance for Earnings Per Share, which established standards regarding the computation of earnings per share by companies that have issued securities other than common stock that contractually entitle the holder to participate in earnings and dividends. The guidance requires earnings available to common shareholders for the period, after deduction of preferred stock preferences, to be allocated between the common and preferred shareholders based on their respective rights to receive dividends. The Company is not required to present basic and diluted net income per share for securities other than common stock; therefore, the net income (loss) per share amounts only pertain to the Company’s common stock. Basic net income (loss) per share is calculated by dividing income (loss) allocable to common shareholders (net income after reduction for any required returns to preferred stock shareholders prior to paying dividends to the common shareholders, assuming current income for the period had been distributed) by the weighted-average number of common shares outstanding, during the period. The Company calculates diluted net income per share using the more dilutive of the 1) treasury stock method, if-converted method, or contingently issuable share method, as applicable, or 2) the two-class method. The Company has used the treasury stock method to calculate diluted net income (loss) per share for the nine months ended September 30, 2021, as the Company was in a net loss position, and used the two-class method for the three months ended September 30, 2021 and the three and nine months ended September 30, 2020, as the if-converted method is anti-dilutive. Diluted net income per share for the three months ended September 30, 2021 and the three and nine months ended September 30, 2020 also reflects the assumed exercise of options outstanding during the period using the treasury stock method, to the extent dilutive. Warrants were excluded from the calculation of diluted net income per share for the three and nine months ended September 30, 2020 as their effect would be anti-dilutive. As a result of the Business Combination, the Company has retroactively restated the weighted average shares outstanding prior to August 25, 2021, to give effect to the Exchange Ratio. The following table sets forth the computation of basic and diluted net income (loss) per share (in thousands, except share and per share data): Three Months Ended Nine Months Ended September 30, September 30, September 30, September 30, Basic Net Income (Loss) per share Net income (loss) $ 8,879 $ ( 7,609 ) $ ( 3,251 ) $ 20,065 Less: income allocated to participating securities — — — ( 19,502 ) Net income (loss) attributable to common shareholders $ 8,879 $ ( 7,609 ) $ ( 3,251 ) $ 563 Weighted average common shares outstanding - basic 16,701,967 1,438,584 6,588,282 1,398,954 Net income (loss) per share - basic $ 0.53 $ ( 5.29 ) $ ( 0.49 ) $ 0.40 Diluted Net Income (Loss) per share Net income (loss) $ 8,879 $ ( 7,609 ) $ ( 3,251 ) $ 20,065 Less: gain on change in fair value of private placement warrants ( 367 ) — — — Less: income allocated to participating securities — — — ( 19,093 ) Net income (loss) attributable to common shareholders $ 8,512 $ ( 7,609 ) $ ( 3,251 ) $ 972 Weighted average common shares outstanding - basic 16,701,967 1,438,584 6,588,282 1,398,954 Weighted average effect of dilutive securities: Stock options 3,302,088 — — 1,106,286 Private placement warrants 1,923 — — — Public warrants 61,737 — — — Weighted average common shares outstanding - diluted 20,067,715 1,438,584 6,588,282 2,505,240 Net income (loss) per share - diluted $ 0.42 $ ( 5.29 ) $ ( 0.49 ) $ 0.39 Potentially dilutive securities as of September 30, 2021 and 2020 are as follows (in common stock equivalent shares): For the Three Months Ended September 30, For the Nine Months Ended September 30, 2021 2020 2021 2020 Series A Convertible Preferred Stock — 11,563,819 — 11,563,819 Series B Convertible Preferred Stock — 10,154,819 — 10,154,819 Series C Convertible Preferred Stock — 6,734,590 — 6,734,590 Series C Convertible Preferred Stock Warrants 108,029 70,455 108,029 70,455 Public warrants — — 5,833,333 — Private placement warrants — — 181,667 — Earn-Out Shares 5,000,000 — 5,000,000 — Unvested sponsor shares 300,000 — 300,000 — Stock options outstanding 64,486 3,630,273 3,978,805 523,893 Total 5,472,515 32,153,956 15,401,834 29,047,576

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Schedule of Computation of Basic and Diluted Net Income (Loss) Per Share	The following table sets forth the computation of basic and diluted net income (loss) per share (in thousands, except share and per share data): Three Months Ended Nine Months Ended September 30, September 30, September 30, September 30, Basic Net Income (Loss) per share Net income (loss) $ 8,879 $ ( 7,609 ) $ ( 3,251 ) $ 20,065 Less: income allocated to participating securities — — — ( 19,502 ) Net income (loss) attributable to common shareholders $ 8,879 $ ( 7,609 ) $ ( 3,251 ) $ 563 Weighted average common shares outstanding - basic 16,701,967 1,438,584 6,588,282 1,398,954 Net income (loss) per share - basic $ 0.53 $ ( 5.29 ) $ ( 0.49 ) $ 0.40 Diluted Net Income (Loss) per share Net income (loss) $ 8,879 $ ( 7,609 ) $ ( 3,251 ) $ 20,065 Less: gain on change in fair value of private placement warrants ( 367 ) — — — Less: income allocated to participating securities — — — ( 19,093 ) Net income (loss) attributable to common shareholders $ 8,512 $ ( 7,609 ) $ ( 3,251 ) $ 972 Weighted average common shares outstanding - basic 16,701,967 1,438,584 6,588,282 1,398,954 Weighted average effect of dilutive securities: Stock options 3,302,088 — — 1,106,286 Private placement warrants 1,923 — — — Public warrants 61,737 — — — Weighted average common shares outstanding - diluted 20,067,715 1,438,584 6,588,282 2,505,240 Net income (loss) per share - diluted $ 0.42 $ ( 5.29 ) $ ( 0.49 ) $ 0.39
Schedule of Potentially Dilutive Securities	Potentially dilutive securities as of September 30, 2021 and 2020 are as follows (in common stock equivalent shares): For the Three Months Ended September 30, For the Nine Months Ended September 30, 2021 2020 2021 2020 Series A Convertible Preferred Stock — 11,563,819 — 11,563,819 Series B Convertible Preferred Stock — 10,154,819 — 10,154,819 Series C Convertible Preferred Stock — 6,734,590 — 6,734,590 Series C Convertible Preferred Stock Warrants 108,029 70,455 108,029 70,455 Public warrants — — 5,833,333 — Private placement warrants — — 181,667 — Earn-Out Shares 5,000,000 — 5,000,000 — Unvested sponsor shares 300,000 — 300,000 — Stock options outstanding 64,486 3,630,273 3,978,805 523,893 Total 5,472,515 32,153,956 15,401,834 29,047,576

Business Combination (Tables)

Business Combination (Tables)	9 Months Ended
	Sep. 30, 2021
Business Combinations [Abstract]
Schedule of Common Stock Outstanding following the Consummation of the Business Combination	The following summarizes the common stock outstanding following the consummation of the Business Combination, PIPE Financing and the automatic cashless exercise of Old eFFECTOR warrants: Shares % Old eFFECTOR Stockholders 30,021,762 74.4 % LWAC Stockholders 521,358 1.3 % LWAC Founders (1) 3,756,250 9.3 % PIPE Investors 6,070,003 15.0 % Total 40,369,373 100.0 % (1) Excludes 300,000 Sponsor Shares subject to vesting that are not considered outstanding from an accounting perspective.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Summary of assets and liabilities measured at fair value on a recurring basis	The following table summarizes the Company’s assets and liabilities that require fair value measurements on a recurring basis and their respective input levels based on the fair value hierarchy as of September 30, 2021 and December 31, 2020 (in thousands): Fair Value Measurements Using September 30, Quoted Prices Significant Significant 2021 Level 1 Level 2 Level 3 Assets Money market funds $ 54,768 $ 54,768 $ — $ — Total assets $ 54,768 $ 54,768 $ — $ — Liabilities Private placement warrant liability $ 1,495 $ — $ — $ 1,495 Earn-out liability 43,250 — — 43,250 Total liabilities $ 44,745 $ — $ — $ 44,745 Fair Value Measurements Using December 31, Quoted Prices Significant Significant 2020 Level 1 Level 2 Level 3 Assets Money market funds $ 15,216 $ 15,216 $ — $ — Total assets $ 15,216 $ 15,216 $ — $ — Liabilities Preferred stock warrant liability $ 433 $ — $ — $ 433 Total liabilities $ 433 $ — $ — $ 433
Preferred Stock Warrant Liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Summary of fair value measurements inputs	The following key assumptions were used in determining the fair value of the preferred stock warrant liability valued using the Black-Scholes option pricing model as of December 31, 2020: December 31, Fair value of Series C convertible preferred stock $ 0.70 Expected volatility 96.3 % Risk-free interest rate 0.7 % Expected term (in years) 7.7 Expected dividend yield —
Summary of change in fair value of derivative warrant liabilities	The following table presents activity for the preferred stock warrant liability measured at fair value using significant unobservable Level 3 inputs during the nine months ended September 30, 2021 and 2020 (in thousands): Series C Preferred Stock Warrant Liability Balance at December 31, 2019 $ 442 Change in fair value 68 Balance at September 30, 2020 $ 510 Balance at December 31, 2020 $ 433 Issuance of new warrants 271 Change in fair value 153 Warrant exercises ( 857 ) Balance at September 30, 2021 $ —
Private Placement Warrants Liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Summary of fair value measurements inputs	The following key assumptions were used in determining the fair value of the private placement warrant liability valued using the Black-Scholes option pricing model as of September 30, 2021 and August 25, 2021: September 30, As of August 25, 2021 at Initial Measurement Common stock price $ 14.05 $ 16.98 Expected volatility 65.0 % 60.0 % Risk-free interest rate 1.0 % 0.8 % Expected term (in years) 4.9 5.0 Expected dividend yield — —
Summary of change in fair value of derivative warrant liabilities	The following table presents activity for the private placement warrant liability measured at fair value using significant unobservable Level 3 inputs during the nine months ended September 30, 2021 (in thousands): Private Placement Warrant Liability Private Placement Warrants liability - August 25, 2021 (closing date) $ 1,862 Change in fair value - Closing Date through September 30, 2021 ( 367 ) Balance at September 30, 2021 $ 1,495

Property and Equipment , net (T

Property and Equipment , net (Tables)	9 Months Ended
	Sep. 30, 2021
Property Plant And Equipment [Abstract]
Summary of Property and Equipment ,net	Property and equipment, net consists of the following (in thousands): September 30, December 31, Lab equipment $ 30 $ 30 Computer and office equipment 124 133 Furniture and fixtures 64 64 Construction in process 2 — 220 227 Less accumulated depreciation and amortization ( 199 ) ( 193 ) $ 21 $ 34

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2021
Payables And Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consist of the following (in thousands): September 30, December 31, Employee compensation $ 803 $ 230 Research and development 702 755 Professional and outside services 760 44 Interest 128 598 Income taxes payable 351 351 Other 4 6 $ 2,748 $ 1,984

Term Loans (Tables)

Term Loans (Tables)	9 Months Ended
	Sep. 30, 2021
Longterm Notes And Loans By Type Current And Noncurrent [Abstract]
Schedule of Principal Future Payments of Term Loans	Based on the outstanding principal amounts for the Company’s Term A Loans, the following table sets forth by year the Company’s required future principal payments as of September 30, 2021 (in thousands): As of September 30, 2021 2023 $ 4,444 2024 6,667 2025 6,667 2026 2,222 Required future principal payments $ 20,000 Unamortized debt discount ( 1,337 ) Non-current term loans, net as of September 30, 2021 $ 18,663

Warrants (Tables)

Warrants (Tables)	9 Months Ended
	Sep. 30, 2021
Warrants and Rights Note Disclosure [Abstract]
Summary of Preferred stock warrants outstanding	The following table summarizes the outstanding warrants to purchase shares of preferred stock and the corresponding exercise price as of September 30, 2021 and December 31, 2020: September 30, December 31, Exercise Price Expiration Date Series C preferred stock warrants — 70,455 $ 5.33 August 31, 2028 Series C preferred stock warrants — — $ 5.33 March 19, 2031
Summary of Public and private placement warrants outstanding.	The following table summarizes the number of outstanding public warrants and private placement warrants and the corresponding exercise price as of September 30, 2021 and December 31, 2020: September 30, December 31, Exercise Price Expiration Date Public warrants 5,833,333 — $ 11.50 August 24, 2026 Private placement warrants 181,667 — $ 11.50 August 24, 2026

Preferred Stock and Stockhold_2

Preferred Stock and Stockholders' Deficit (Tables)	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Schedule of Convertible Preferred Stock and Common Stock	The authorized shares, purchase price, number of shares and liquidation amount for each series of convertible preferred stock as of December 31, 2020, as adjusted for the Exchange Ratio, is as follows (in thousands, except share and per share amounts): Shares Purchase Shares Liquidation Convertible preferred stock: Series A 14,056,840 $ 4.05382 11,563,819 $ 46,878 Series B 11,071,448 $ 5.05806 10,154,819 $ 51,364 Series C 7,346,140 $ 5.32253 6,734,590 $ 35,845 Total 32,474,428 28,453,228 $ 134,087
Summary of option activity under the company's plans	A summary of the Company’s stock option activity under the plans is as follows (in thousands, except share and per share amounts and years): Shares Weighted- Weighted- Aggregate Outstanding at December 31, 2020 3,887,038 $ 1.41 6.6 $ 3,806 Granted 204,512 10.28 9.8 Exercised ( 72,940 ) 1.06 4.5 Cancelled ( 39,805 ) 1.38 7.2 Outstanding at September 30, 2021 3,978,805 $ 1.87 6.1 $ 48,898 Vested and exercisable at September 30, 2021 2,912,657 $ 1.26 5.0 $ 37,248
Schedule of assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock option grants.	The assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock option grants were as follows: Nine Months Ended September 30, 2021 2020 Risk-free interest rate 0.7 % - 0.9 % 0.3 % - 1.0 % Expected volatility 82 % - 90 % 87 % - 93 % Expected term (in years) 5.5 - 6.1 5.3 - 6.1 Expected dividend yield 0 % 0 %
Schedule of Common Stock, Reserved for Future Issuance	Common stock reserved for future issuance consists of the following as of September 30, 2021 and December 31, 2020: September 30, December 31, Convertible preferred stock — 28,453,228 Stock options issued and outstanding 3,978,805 3,887,038 Preferred stock warrants issued and outstanding — 70,455 Public warrants issued and outstanding 5,833,333 — Private placement warrants issued and outstanding 181,667 — Earn-Out shares 5,000,000 — Unvested sponsor shares 300,000 — Authorized for future stock awards or option grants 6,441,852 132,974 Total 21,735,657 32,543,695

Earn-out Shares (Tables)

Earn-out Shares (Tables)	9 Months Ended
	Sep. 30, 2021
Earn out Share [Abstract]
Schedule Of Estimated Fair Value Of The Earn Out Shares	The estimated fair value of the Earn-Out Shares was determined using a Monte Carlo simulation valuation model using a distribution of potential outcomes on a monthly basis over the Earn-Out Period using the most reliable information available. Assumptions used in the valuation were as follows: September 30, As of August 25, 2021 at Initial Measurement Stock price $ 14.05 $ 16.98 Expected volatility 65.0 % 60.0 % Risk-free interest rate 0.3 % 0.2 % Forecast period (in years) 1.9 2.0 Cost of equity 20.0 % 20.0 %
Schedule Of Activity For Earn Out Liability	The following table presents activity for the Earn-Out liability measured at fair value using significant unobservable Level 3 inputs at the Merger close date (August 25, 2021) and September 30, 2021 (in thousands): Earn-out Liability Earn-out liability - August 25, 2021 (Closing Date) $ 61,024 Incremental shares due to option holder forfeitures 16 Change in fair value - Closing Date through September 30, 2021 ( 17,790 ) Balance at September 30, 2021 $ 43,250

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Schedule of Supplemental Balance sheet Information related to Leases	The following table summarizes supplemental balance sheet information related to leases as of September 30, 2021 and December 31, 2020. September 30, December 31, Assets: Operating lease right-of-use assets $ 24 $ 92 Total right-of-use assets 24 92 Liabilities Operating lease liabilities, current 28 108 Operating lease liabilities, non-current — — Total operating lease liabilities $ 28 $ 108
Schedule of Future Minimum Rental Payments for Operating Leases	As of September 30, 2021, the future minimum annual lease payments under the existing operating leases were as follows (in thousands, except for weighted-average remaining lease term and weighted-average discount rate): In thousands (except for Weighted-average remaining lease term and Weighted-average discount rate) Remainder of 2021 $ 28 Total remaining lease payments 28 Less: imputed interest - Total operating lease liabilities 28 Less: current portion ( 28 ) Long-term operating lease liabilities $ - Weighted-average remaining lease term ( in years ) - Weighted-average discount rate 9 %

Organization and Basis of Pre_2

Organization and Basis of Presentation - Additional Information (Detail) $ in Thousands	Aug. 25, 2021USD ($)	Sep. 30, 2021USD ($)	Dec. 31, 2020USD ($)	Sep. 30, 2020USD ($)	Dec. 31, 2019USD ($)
Subsidiary Sale Of Stock [Line Items]
Place of incorporation		DE
Accumulated deficit		$ 139,950	$ 136,699
Cash from operation		19,900
Cash and cash equivalents		$ 54,768	$ 15,216	$ 24,337	$ 3,427
Proceeds from cash acquired through acquisition and PIPE offering	$ 67,000
PIPE Investors
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock	$ 60,700
Locust Walk Acquisition Corp [Member]
Subsidiary Sale Of Stock [Line Items]
Conversion of outstanding common and preferred shares into common shares	0.09657

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock, shares issued	40,669,373	1,445,065
Common stock price per share	$ 0.0001	$ 0.0001
Consecutive trading days required for entitlement of common stock	30 days
Earn-Out Shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock, shares issued	5,000,000
Common stock price per share	$ 20
Trading days required for entitlement of common stock	20 days
Consecutive trading days required for entitlement of common stock	30 days

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of basic and diluted net income (loss) per share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Basic Net Income (Loss) per share
Net income (loss)	$ 8,879	$ (7,609)	$ (3,251)	$ 20,065
Less: income allocated to participating securities	0	0	0	(19,502)
Net income (loss) attributable to common shareholders	$ 8,879	$ (7,609)	$ (3,251)	$ 563
Weighted average common shares outstanding - basic	16,701,967	1,438,584	6,588,282	1,398,954
Net income (loss) per share - Basic	$ 0.53	$ (5.29)	$ (0.49)	$ 0.40
Diluted Net income (Loss) per share
Net income (loss)	$ 8,879	$ (7,609)	$ (3,251)	$ 20,065
Net income (loss) attributable to common shareholders	$ 8,512	$ (7,609)	$ (3,251)	$ 972
Weighted average common shares outstanding - basic	16,701,967	1,438,584	6,588,282	1,398,954
Weighted average common shares outstanding - diluted	20,067,715	1,438,584	6,588,282	2,505,240
Net income (loss) per share - diluted	$ 0.42	$ (5.29)	$ (0.49)	$ 0.39
Public Warrants [Member]
Diluted Net income (Loss) per share
Weighted average effect of dilutive securities	61,737			0
Private Placement Warrants [Member]
Diluted Net income (Loss) per share
Less: gain on change in fair value of warrants	$ (367)
Weighted average effect of dilutive securities	1,923
Series C Convertible Preferred Stock Warrants [Member]
Diluted Net income (Loss) per share
Less: income allocated to participating securities	$ 0		$ 0	$ (19,093)
Weighted average common shares outstanding - diluted	20,067,715		6,588,282
Stock Options [Member]
Diluted Net income (Loss) per share
Weighted average effect of dilutive securities	3,302,088

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	5,472,515	32,153,956	15,401,834	29,047,576
Series A Preferred Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)		11,563,819		11,563,819
Series B Preferred Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)		10,154,819		10,154,819
Series C Preferred Stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)		6,734,590		6,734,590
Series C Convertible Preferred Stock Warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	108,029	70,455	108,029	70,455
Public warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)			5,833,333
Private Placement [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)			181,667
Earn-Out Shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	5,000,000		5,000,000
Unvested sponsor shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	300,000		300,000
Stock Options Outstanding [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Dilutive Securities (in common stock equivalent shares)	64,486	3,630,273	3,978,805	523,893

Business Combination - Addition

Business Combination - Additional Information (Detail) $ / shares in Units, $ in Thousands	Aug. 25, 2021USD ($)$ / sharesshares	Sep. 30, 2021USD ($)	Dec. 31, 2020USD ($)
Business Acquisition [Line Items]
Trading Days Required For Entitlement Of Common Stock 1		20 days
Business acquisition transaction cost | $	$ 3,000
Liabilities | $		$ 67,605	$ 15,725
Proceeds from cash acquired through acquisition and PIPE offering | $	67,000
Proceeds from business combination | $	52,900
Cash acquired | $	6,300
Transaction costs paid by SPAC in business combination | $	11,100
Private Investment In Public Entity Offering [Member]
Business Acquisition [Line Items]
Issuance of common stock | $	$ 60,700
Old eFFECTOR Stockholders
Business Acquisition [Line Items]
Preferred stock conversion ratio	0.09657
Exchange ratio of outstanding stock and options	0.09657
Shares issued on conversion | shares	30,021,762
Option to purchase common stock | shares	3,920,657
Weighted average exercise price of stock options that were exchanged | $ / shares	$ 1.56
Old eFFECTOR Stockholders | Earn-Out Shares
Business Acquisition [Line Items]
Contingently issuable shares issued to shareholders and option holders | shares	5,000,000
Contingently issuable shares description	Former holders of shares of Old eFFECTOR common stock (including shares received as a result of the conversion of Old eFFECTOR preferred stock and the exercise of Old eFFECTOR warrants) and former holders of options to purchase shares of Old eFFECTOR will also be entitled to receive their pro rata share of up to 5,000,000 earn-out shares (the "Earn-Out Shares") of Common Stock if, on or prior to August 26, 2023, the closing share price of shares of common stock equals or exceeds $20.00 over at least 20 trading days within a 30-day trading period (the “Triggering Event”) and, in respect of each former holder of Old eFFECTOR stock options, such holder continues to provide services to the Company or one of its subsidiaries at the time of such Triggering Event. The Earn-Out Shares will also be earned and issuable in the event of a change in control of the Company on or prior to August 26, 2023 that results in the holders of common stock receiving a per-share price equal to or in excess of $20.00.
Old eFFECTOR Stockholders | Earn-Out Shares | Minimum
Business Acquisition [Line Items]
Trigger price of common stock for issuance of earnout shares | $ / shares	$ 20
Trading Days Required For Entitlement Of Common Stock 1	20 days
Old eFFECTOR Stockholders | Earn-Out Shares | Maximum
Business Acquisition [Line Items]
Trading Days Required For Entitlement Of Common Stock 1	30 days
Old eFFECTOR Stockholders | Common Stock [Member]
Business Acquisition [Line Items]
Common stock up on conversion | shares	4,056,250
PIPE Investor
Business Acquisition [Line Items]
Business acquisition, equity interest issued or issuable, number of shares | shares	6,070,003
Business acquisition share price | $ / shares	$ 10
Business acquisition, equity interest issued or issuable value assigned | $	$ 60,700
Stock issued, Shares, Acquisitions | shares	40,669,373
Stock Outstanding During Period Shares Acquisitions | shares	40,369,373
LWAC Stockholders
Business Acquisition [Line Items]
Business acquisition, equity interest issued or issuable, number of shares | shares	10,347,611
Liabilities | $	$ 900
LWAC Stockholders | Common Stock Subject to Vesting
Business Acquisition [Line Items]
Common stock up on conversion | shares	300,000
LWAC Stockholders | Common Stock Subject to Vesting | Minimum
Business Acquisition [Line Items]
Trading Days Required For Entitlement Of Common Stock 1	20 days
Trigger price of common stock for vesting of unvested shares | $ / shares	$ 15
LWAC Stockholders | Common Stock Subject to Vesting | Maximum
Business Acquisition [Line Items]
Trading Days Required For Entitlement Of Common Stock 1	30 days

Business Combination - Summary

Business Combination - Summary of common stock outstanding following the consummation of business combination (Detail) - shares		9 Months Ended
		Sep. 30, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Common stock, shares outstanding		40,369,373	1,445,065
Common stock, shares outstanding		40,369,373
Percentage of ownership		100.00%
Old eFFECTOR Stockholders
Business Acquisition [Line Items]
Common stock, shares outstanding		30,021,762
Percentage of ownership		74.40%
LWAC Stockholders
Business Acquisition [Line Items]
Common stock, shares outstanding		521,358
Percentage of ownership		1.30%
LWAC Founders
Business Acquisition [Line Items]
Common stock, shares outstanding	[1]	3,756,250
Percentage of ownership	[1]	9.30%
PIPE Investors
Business Acquisition [Line Items]
Common stock, shares outstanding		6,070,003
Percentage of ownership		15.00%
[1]	Excludes 300,000 Sponsor Shares subject to vesting that are not considered outstanding from an accounting perspective.

Business Combination - Summar_2

Business Combination - Summary of common stock outstanding following the consummation of business combination (Parenthetical) (Detail) - shares	Sep. 30, 2021	Dec. 31, 2020
Business Combinations [Abstract]
Unvested Shares Held By Sponsors	300,000

Fair Value Measurementsn - Addi

Fair Value Measurementsn - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Inputs, Level 1, 2 and 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value, net derivative asset (liability) measured on recurring basis, unobservable inputs reconciliation, transfers, net	$ 0	$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Assets And Liabilities Measured At Fair Value On Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Liabilities
Earn-out liability	$ 43,250	$ 0
Fair Value, Recurring
Assets
Total assets	54,768	15,216
Liabilities
Earn-out liability	43,250
Total liabilities	44,745	433
Fair Value, Recurring | Private Placement Warrant Liability
Liabilities
Warrant liability	1,495
Fair Value, Recurring | Preferred Stock Warrant Liability [Member]
Liabilities
Preferred stock warrant liability		433
Fair Value, Recurring | Fair Value Inputs Level 1
Assets
Total assets	54,768	15,216
Fair Value, Recurring | Fair Value Inputs Level 3
Liabilities
Earn-out liability	43,250
Total liabilities	44,745	433
Fair Value, Recurring | Fair Value Inputs Level 3 | Private Placement Warrant Liability
Liabilities
Warrant liability	1,495
Fair Value, Recurring | Fair Value Inputs Level 3 | Preferred Stock Warrant Liability [Member]
Liabilities
Preferred stock warrant liability		433
Fair Value, Recurring | Money Market Funds
Assets
Money market funds	54,768	15,216
Fair Value, Recurring | Money Market Funds | Fair Value Inputs Level 1
Assets
Money market funds	$ 54,768	$ 15,216

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of fair value measurements inputs of preferred stock warrant liability (Detail) - Preferred Stock Warrant Liability [Member]	Dec. 31, 2020sharesyr
Expected volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input	96.3
Risk-free interest rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input	0.7
Expected term (in years)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input | yr	7.7
Expected dividend yield
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input	0
Series C Convertible Preferred Stock [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input | shares	0.70

Fair Value Measurements - Sum_3

Fair Value Measurements - Summary of change in fair value of preferred stock warrant liability (Detail) - Series C Preferred Stock Warrant Liability [Member] - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value, Beginning Balance	$ 433	$ 442
Issuance of new warrants	271
Change in fair value	153	68
Warrant exercises	(857)
Fair value, Ending Balance	$ 0	$ 510

Fair Value Measurements - Sum_4

Fair Value Measurements - Summary of fair value measurements inputs of private placement warrant liability (Detail) - Private Placement Warrant Liability	Sep. 30, 2021sharesyr	Aug. 25, 2021yrshares
Common Stock Price
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input | shares	14.05	16.98
Expected volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input	65	60
Risk-free interest rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input	1	0.8
Expected term (in years)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input | yr	4.9	5
Expected dividend yield
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Measurement Input	0	0

Fair Value Measurements - Sum_5

Fair Value Measurements - Summary of change in fair value of private placement warrant liability (Detail) - Private Placement Warrant Liability $ in Thousands	1 Months Ended
	Sep. 30, 2021USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value, Beginning Balance	$ 1,862
Change in fair value	367
Fair value, Ending Balance	$ 1,495

Property and Equipment, net - S

Property and Equipment, net - Summary of Property and Equipment, net (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	$ 220	$ 227
Less accumulated depreciation and amortization	(199)	(193)
Property and Equipment, Net	21	34
Lab Equipment
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	30	30
Computer And Office Equipment
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	124	133
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	64	64
Construction In Progress
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	$ 2	$ 0

Property and Equipment, net - A

Property and Equipment, net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Property Plant And Equipment [Abstract]
Depreciation and amortization	$ 6	$ 40	$ 20	$ 127

Accrued Expenses - Summary of A

Accrued Expenses - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Employee compensation	$ 803	$ 230
Research and development	702	755
Professional and outside services	760	44
Interest	128	598
Income taxes payable	351	351
Other	4	6
Accrued Liabilities, Current	$ 2,748	$ 1,984

Term Loans - Additional Informa

Term Loans - Additional Information (Detail)	Aug. 31, 2018USD ($)	Mar. 31, 2021USD ($)Tranche	Sep. 30, 2021USD ($)WarrantTranche$ / sharesshares	Sep. 30, 2020USD ($)	Sep. 30, 2021USD ($)WarrantTranche$ / sharesshares	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)shares	Aug. 31, 2019USD ($)
Debt Instrument [Line Items]
Number of tranches | Tranche			3		3
Ceiling limit of maximum percentage amount to be paid on aggregate principal amount	5.50%
Debt Instrument, Maturity Date	Feb. 1, 2023
Exercise price of warrants | $ / shares			$ 5.33		$ 5.33
Number of warrants | Warrant			2		2
Effective interest rate							1.50%
Outstanding principal, Term loans			$ 18,663,000		$ 18,663,000
Accrued final payment on term loans			1,100,000		1,100,000		$ 0
Loss on debt extinguishment			0	$ 0	(492,000)	$ 0
Issuance of term loans, net of issuance costs					19,835,000
Long term debt net of unamortized debt discounts			$ 20,000,000		$ 20,000,000
Prime Rate [Member]
Debt Instrument [Line Items]
Effective interest rate							6.50%
Series C Preferred Stock [Member]
Debt Instrument [Line Items]
Exercise price of warrants | $ / shares			$ 5.33		$ 5.33
Number of shares subject to each warrant | shares			46,970		46,970
Debt Instrument, Term Loan A [Member]
Debt Instrument [Line Items]
Effective interest rate							9.10%
Debt Instrument, Term Loan B [Member]
Debt Instrument [Line Items]
Effective interest rate							9.00%
Loan and Security Agreement [Member]
Debt Instrument [Line Items]
Line of credit facility, Maximum borrowing amount	$ 20,000,000
Line of credit facility, Interest rate description	The Term Loans had an interest-only period that commenced upon the borrowing of each tranche of the Term Loans with interest due and payable upon the first day of each month. The interest-only period ended August 31, 2020.
Number of shares subject to each warrant | shares							35,227
Loan and Security Agreement [Member] | Less Than One Year From The Date Of Loan Agreement [Member]
Debt Instrument [Line Items]
Prepayment fee as a percentage of the outstanding principal		3.00%
Loan and Security Agreement [Member] | Greater Than One Year And Less Than Two Years From The Date Of Loan Agreement [Member]
Debt Instrument [Line Items]
Prepayment fee as a percentage of the outstanding principal		2.00%
Loan and Security Agreement [Member] | Later Than Two Years And Not Later Than Three Years From The Date Of Loan Agreement [Member]
Debt Instrument [Line Items]
Prepayment fee as a percentage of the outstanding principal		1.00%
Loan and Security Agreement [Member] | Later Than Three Years From The Date Of Loan Agreement [Member]
Debt Instrument [Line Items]
Prepayment fee as a percentage of the outstanding principal		0.00%
Loan and Security Agreement [Member] | Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Debt Instrument, Discount			$ 200,000		$ 200,000
Outstanding principal, Term loans							$ 13,000,000
Debt discount costs, net							$ 12,900,000
Amortization of debt discount			$ 0	$ 300,000	$ 200,000	$ 1,000,000
Accrued final payment on term loans		$ 37,000
Loss on debt extinguishment		500,000
Prepayment fees paid in respect of term loan		$ 100,000
Loan and Security Agreement [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Number of tranches | Tranche		2
Line of credit facility, Interest rate description		The Term A Loans have an interest-only period that commences upon the borrowing with interest due and payable upon the first day of each month. The interest-only period ends May 1, 2023
Debt instrument, face amount		$ 30,000,000
Long term debt variable interest rate percentage		7.70%
Loan and Security Agreement [Member] | Prime Rate [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Debt instrument variable interest rate spread		4.45%
Loan and Security Agreement [Member] | Warrants To Purchase Series C Redeemable Convertible Stock | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Exercise price of warrants | $ / shares			$ 5.33		$ 5.33
Number of shares subject to each warrant | shares			37,575		37,575
Loan and Security Agreement [Member] | Common Stock [Member] | Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Common stock up on conversion | shares					16,477
Loan and Security Agreement [Member] | Common Stock [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Common stock up on conversion | shares					17,575
Loan and Security Agreement [Member] | Debt Instrument, Term Loan A [Member]
Debt Instrument [Line Items]
Line of credit facility, Current borrowing amount	$ 7,500,000
Loan and Security Agreement [Member] | Debt Instrument, Term Loan A [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date		Mar. 18, 2026
Debt Instrument, Discount			$ 1,500,000		$ 1,500,000
Outstanding principal, Term loans		$ 20,000,000	20,000,000		20,000,000
Amortization of debt discount			500,000		1,000,000
Issuance of term loans, net of issuance costs		$ 12,500,000
Cut off date before which the interest on the term loan shall be paid		May 1, 2023
Extended cut off date before which the interest on term loan shall be paid		May 1, 2024
Term loan final payment as a percentage of the amount funded		5.50%
Long term debt net of unamortized debt discounts			$ 18,700,000		$ 18,700,000
Loan and Security Agreement [Member] | Debt Instrument, Term Loan B [Member]
Debt Instrument [Line Items]
Line of credit facility, Current borrowing amount	7,500,000							$ 7,500,000
Loan and Security Agreement [Member] | Debt Instrument, Term Loan B [Member] | Oxford Finance LLC [Member]
Debt Instrument [Line Items]
Debt instrument, face amount		$ 10,000,000
Issuance of term loans, net of issuance costs		$ 7,400,000
Loan initiation date		May 31, 2022
Number of days within which a portion of term loan will be available subject to achievement of milestone		45 days
Loan and Security Agreement [Member] | Debt Instrument, Term Loan C [Member]
Debt Instrument [Line Items]
Line of credit facility, Current borrowing amount	$ 5,000,000
Loan and Security Agreement [Member] | Debt Instrument Term Loan A and B [Member] | Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Repayment of term loans		$ 11,500,000
Term loan final payment		$ 800,000
Term loan final payment as a percentage of the original principal amount		1.00%

Term Loans - Schedule of Princi

Term Loans - Schedule of Principal Future Payments of Term Loans (Detail) $ in Thousands	Sep. 30, 2021USD ($)
Longterm Notes And Loans By Type Current And Noncurrent [Abstract]
2023	$ 4,444
2024	6,667
2025	6,667
2026	2,222
Required future principal payments	20,000
Unamortized debt discount	(1,337)
Non-current term loans, net as of September 30, 2021	$ 18,663

Warrants - Additional Informati

Warrants - Additional Information (Detail) - $ / shares	Aug. 25, 2021	Sep. 30, 2021
Class of Warrant or Right [Line Items]
Exercise price of warrants		$ 5.33
Public Warrants and Private Placement Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants exercisable term from the date of completion of business combination		30 days
Exercise price of warrants		$ 11.50
Class of warrants, redemption price per unit		$ 0.01
Class of warrants, redemption notice period		30 days
Share price		$ 18
Warrants and rights outstanding, term		5 years
Number of consecutive trading days for determining share price		20 days
Number of trading days to determine share price		30 days
Preferred Stock Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants exercise	50,529
Stockholders equity note stock split exchange ratio	0.09657

Warrants - Summary of Preferred

Warrants - Summary of Preferred stock warrants outstanding (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Class Of Stock [Line Items]
Class of Warrant or Right, Outstanding
Exercise price of warrants	$ 5.33
Expiration date	Mar. 19, 2031
Series C Preferred Stock Warrant [Member]
Class Of Stock [Line Items]
Class of Warrant or Right, Outstanding		70,455
Exercise price of warrants	$ 5.33
Expiration date	Aug. 31, 2028

Warrants - Schedule of Public a

Warrants - Schedule of Public and private placement warrants outstanding (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding
Exercise price of warrants	$ 5.33
Expiration date	Mar. 19, 2031
Public Warrants [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	5,833,333
Exercise price of warrants	$ 11.50
Expiration date	Aug. 24, 2026
Private Placement Warrants [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Outstanding	181,667
Exercise price of warrants	$ 11.50
Expiration date	Aug. 24, 2026

Preferred Stock and Stockhold_3

Preferred Stock and Stockholders Deficit - Schedule of Convertible Preferred Stock (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Temporary Equity [Line Items]
Shares Authorized				32,474,428
Shares Outstanding				28,453,228
Liquidation Preference				$ 134,087
Series A Preferred Stock [Member]
Temporary Equity [Line Items]
Shares Authorized				14,056,840
Purchase Price Per Share				4.05382
Shares Outstanding	0	11,563,819	11,563,819	11,563,819	11,563,819	11,563,819	11,563,819	11,563,819
Liquidation Preference				$ 46,878
Series B Preferred Stock [Member]
Temporary Equity [Line Items]
Shares Authorized				11,071,448
Purchase Price Per Share				5.05806
Shares Outstanding	0	10,154,819	10,154,819	10,154,819	10,154,819	10,154,819	10,154,819	10,154,819
Liquidation Preference				$ 51,364
Series C Preferred Stock [Member]
Temporary Equity [Line Items]
Shares Authorized				7,346,140
Purchase Price Per Share				5.32253
Shares Outstanding	0	6,734,590	6,734,590	6,734,590	6,734,590	6,734,590	6,734,590	6,734,590
Liquidation Preference				$ 35,845

Preferred Stock and Stockhold_4

Preferred Stock and Stockholders' Deficit - Additional Information (Detail)	Aug. 25, 2021$ / sharesshares	Sep. 30, 2021USD ($)$ / sharesshares	Jun. 30, 2021USD ($)shares	Sep. 30, 2020USD ($)shares	Jun. 30, 2020USD ($)shares	Mar. 31, 2020USD ($)shares	Sep. 30, 2021USD ($)$ / sharesshares	Sep. 30, 2020USD ($)shares	Dec. 31, 2020$ / sharesshares
Class Of Stock [Line Items]
Preferred Stock, Shares authorized	100,000,000	100,000,000					100,000,000		0
Preferred stock, par value | $ / shares	$ 0.0001	$ 0.0001					$ 0.0001		$ 0.0001
Preferred stock, shares issued		0					0		0
Convertible preferred stock exchange ratio	0.09657
Preferred stock, shares outstanding	28,453,228	0					0		0
Stock option exercises | $		$ 63,000	$ 15,000	$ 20,000	$ 72,000	$ 16,000	$ 78,000	$ 108,000
Stock options outstanding		3,978,805					3,978,805		3,887,038
Stock option exercises, shares		57,489		16,899			72,940	111,354
Number of Option Outstanding,Granted							204,512
Share-based Payment Award, Expiration Period							10 years
Share-based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit | $ / shares							$ 100
Share-based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit | $ / shares							$ 110
Sharebased Compensation Arrangement By Sharebased Payment Award Award Vesting Rights Percentage							25.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period							3 years
Fair value of vested option | $							$ 500,000
Weighted-average grant date fair value | $ / shares							$ 7.18
Share-based Payment Arrangement, Expense | $		$ 200,000		$ 200,000			$ 600,000	$ 300,000
Unrecognized compensation cost related to outstanding employee options | $							$ 1,700,000
Expected term (in years)							1 year
Unrecognized compensation cost related to outstanding nonemployee options | $							$ 800,000
Outstanding non employee expense expected period							6 months
Maximum [Member]
Class Of Stock [Line Items]
Expected term (in years)							6 years 1 month 6 days	6 years 1 month 6 days
Holder of More Than 10% [Member]
Class Of Stock [Line Items]
Share-based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit | $ / shares							$ 10
2013, Equity Incentive Plan
Class Of Stock [Line Items]
Stock options outstanding	3,920,657
Shares authorized		3,914,319					3,914,319		4,594,060
Adjusted weighted-average exercise price per share | $ / shares	$ 1.56
Number of shares reserved for future issuance		0					0		132,974
Shares grants		0					0		132,974
2021, Equity Incentive Plan
Class Of Stock [Line Items]
Shares authorized		6,506,338					6,506,338		0
Shares purchased for award							64,486
Number of shares reserved for future issuance		6,441,852					6,441,852
Shares grants		6,441,852					6,441,852
2021 Employee Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Number of shares reserved for future issuance		880,000					880,000
Shares grants		880,000					880,000
Number of Option Outstanding,Granted							0
2021 Employee Stock Purchase Plan [Member] | Maximum [Member]
Class Of Stock [Line Items]
Number of shares reserved for future issuance		15,000,000					15,000,000
Shares grants		15,000,000					15,000,000
Common Stock [Member]
Class Of Stock [Line Items]
Preferred stock, shares outstanding	28,453,228
Stock option exercises, shares		57,489	15,451	16,899	75,540	18,915
Common Stock [Member] | 2013, Equity Incentive Plan
Class Of Stock [Line Items]
Shares purchased for award	3,920,657
Old eFACTOR Common Stock [Member] | 2013, Equity Incentive Plan
Class Of Stock [Line Items]
Shares purchased for award	40,599,270
Series A Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred Stock, Shares authorized		0					0		14,056,840
Preferred stock, par value | $ / shares		$ 0.0001					$ 0.0001		$ 0.0001
Preferred stock, shares issued		0					0		11,563,819
Preferred stock, shares outstanding	11,563,819	0					0		11,563,819
Series B Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred Stock, Shares authorized		0					0		11,071,448
Preferred stock, par value | $ / shares		$ 0.0001					$ 0.0001		$ 0.0001
Preferred stock, shares issued		0					0		10,154,819
Preferred stock, shares outstanding	10,154,819	0					0		10,154,819
Series C Preferred Stock [Member]
Class Of Stock [Line Items]
Preferred Stock, Shares authorized		0					0		7,346,140
Preferred stock, par value | $ / shares		$ 0.0001					$ 0.0001		$ 0.0001
Preferred stock, shares issued		0					0		6,734,590
Preferred stock, shares outstanding	6,734,590	0					0		6,734,590

Preferred Stock and Stockhold_5

Preferred Stock and Stockholders Deficit - Summary of Option Activity Under the Company's Plans (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Equity [Abstract]
Number of Option Outstanding,Beginning balance			3,887,038
Number of Option Outstanding,Granted			204,512
Number of Option Outstanding,Exercised	(57,489)	(16,899)	(72,940)	(111,354)
Number of Option Outstanding,Cancelled			(39,805)
Number of Option Outstanding,Ending balance	3,978,805		3,978,805		3,887,038
Number of Option Exercisable	2,912,657		2,912,657
Weighted Average Exercise Price,Beginning balance			$ 1.41
Weighted Average Exercise Price,Granted			10.28
Weighted average exercise price,Exercised			1.06
Weighted average exercise price,Cancelled			1.38
Weighted Average Exercise Price,Ending balance	$ 1.87		1.87		$ 1.41
Weighted Average Exercise Price,Exercisable	$ 1.26		$ 1.26
Weighted- Average Remaining Contractual Term,Beginning balance			6 years 1 month 6 days		6 years 7 months 6 days
Weighted- Average Remaining Contractual Term,Granted			9 years 9 months 18 days
Weighted- Average Remaining Contractual Term,Exercised			4 years 6 months
Weighted- Average Remaining Contractual Term,Cancelled			7 years 2 months 12 days
Weighted- Average Remaining Contractual Term, Ending balance			6 years 1 month 6 days		6 years 7 months 6 days
Weighted- Average Remaining Contractual Term,Exercisable			5 years
Aggregate Intrinsic Value,Beginning balance			$ 3,806
Aggregate Intrinsic Value,Ending balance	$ 48,898		48,898		$ 3,806
Aggregate Intrinsic Value,Exercisable	$ 37,248		$ 37,248

Preferred Stock and Stockhold_6

Preferred Stock and Stockholders' Deficit - Schedule of assumptions used in the Black-Scholes option pricing model to determine the fair value of the stock option grants (Detail)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	1 year
Expected dividend yield	0.00%	0.00%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	0.70%	0.30%
Expected volatility	82.00%	87.00%
Expected term (in years)	5 years 6 months	5 years 3 months 18 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	0.90%	1.00%
Expected volatility	90.00%	93.00%
Expected term (in years)	6 years 1 month 6 days	6 years 1 month 6 days

Preferred Stock and Stockhold_7

Preferred Stock and Stockholders' Deficit - Summary of Common Stock Reserved for Future Issuance (Detail) - shares	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Class Of Stock [Line Items]
Preferred stock, shares issued	0	0
Stock options issued and outstanding	3,978,805	3,887,038
Class of Warrant or Right, Outstanding
Unvested Shares Held By Sponsors	300,000
Authorized for future stock awards or option grants	6,441,852	132,974
Total	21,735,657	32,543,695
Preferred Stock Warrants
Class Of Stock [Line Items]
Warrants Issued And Outstanding		70,455
Public Warrants Issued and Outstanding
Class Of Stock [Line Items]
Class of Warrant or Right, Outstanding	5,833,333
Private Placement Warrants Issued and Outstanding
Class Of Stock [Line Items]
Class of Warrant or Right, Outstanding	181,667
Convertible Preferred Stock
Class Of Stock [Line Items]
Preferred stock, shares issued		28,453,228
Common Stock [Member]
Class Of Stock [Line Items]
Stock options issued and outstanding	3,978,805	3,887,038
Earn-Out Shares
Class Of Stock [Line Items]
Earn-Out shares	5,000,000

Earn-Out Shares - Additional In

Earn-Out Shares - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Aug. 25, 2021	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Consecutive trading days required for entitlement of common stock			30 days
Trading days required for entitlement of common stock			20 days
Common stock price per share		$ 0.0001	$ 0.0001		$ 0.0001
Non-current warrant liability		$ 1,495	$ 1,495		$ 0
Decrease in the warrant liability			(213)	$ 68
Gain on change in fair value of earn-out liability		$ 17,800	$ 17,790
Common stock, shares issued		40,669,373	40,669,373		1,445,065
Effector Therapeutics Inc [Member]
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Business acquisition, equity interest issued or issuable, number of shares			5,000,000
Common stock price per share		$ 20	$ 20
Earn-Out Shares [Member]
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Fair value of earn-out shares	$ 13.79		$ 9.77
Fair value of option holder Earn-out Shares	$ 7,900
Share based compensation		$ 2,100	$ 2,100
Share based compensation service period	4 months 9 days
Unrecognized compensation expense		5,800	$ 5,800
Unrecognized compensation expense expected to be recognized			3 months 7 days
Estimated fair value of Earn-out Shares		$ 61,000	$ 61,000
Earn-Out Shares [Member] | Stockholders [Member]
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Common stock, shares issued	4,425,258	4,426,889	4,426,889
Earn-Out Shares [Member] | Option Holders [Member]
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Common stock, shares issued	574,742	573,111	573,111

Earn-Out Shares - Summary of Es

Earn-Out Shares - Summary of Estimated Fair Value of Earn-Out Shares (Detail) - Earn-Out Shares [Member]	Sep. 30, 2021sharesyr	Aug. 25, 2021sharesyr
Common Stock Price
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input | shares	14.05	16.98
Expected volatility
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.650	0.600
Forecast period (in years)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input | yr	1.9	2
Risk-free interest rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.003	0.002
Cost of equity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.200	0.200

Earn-Out Shares - Summary of Ac

Earn-Out Shares - Summary of Activity for Earn-Out Liability (Detail) - Earn- out Liability [Member] - Fair Value Inputs Level3 [Member] $ in Thousands	1 Months Ended
	Sep. 30, 2021USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, Beginning Balance	$ 61,024
Incremental shares due to option holder forfeitures	16
Change in fair value	(17,790)
Fair value, Ending Balance	$ 43,250

License Agreements - Additional

License Agreements - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2013	Aug. 31, 2021	Jul. 31, 2021
License Agreement Disclosure [Line Items]
Payable in connection with the closing of the merger agreement	$ 1,000,000		$ 1,000,000
Research and development	5,022,000	$ 6,780,000	13,562,000	$ 17,231,000
Regents of the University of California [Member]
License Agreement Disclosure [Line Items]
Payment of one time license issuance fees					$ 50,000,000
Payable in connection with the closing of the merger agreement						$ 1,000,000
Research and development	$ 15,000	$ 15,000	$ 15,000	$ 15,000
Regents of the University of California [Member] | Amendment to the License Agreement [Member]
License Agreement Disclosure [Line Items]
Payable in connection with the closing of the merger agreement							$ 1,000,000
Terminate agreement period for written notice					60 days
Regents of the University of California [Member] | Amendment to the License Agreement [Member] | Certain Clinical and Regulatory Milestones [Member]
License Agreement Disclosure [Line Items]
Remaining milestone payments payable							$ 375,000

Research Collaboration and Li_2

Research Collaboration and License Agreement - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Research Collaboration And License Agreement [Line Items]
Performance obligation transaction price		$ 27,000		$ 27,000
Revenue from contract with customer excluding assessed tax		427	$ 574	1,119	$ 41,958
Contract with customer liability			42		42
Based on License [Member]
Research Collaboration And License Agreement [Line Items]
Performance obligation transaction price		25,600		25,600
Based on Research Activities [Member]
Research Collaboration And License Agreement [Line Items]
Performance obligation transaction price		$ 1,400		1,400
Early Development and Regulatory Milestones [Member]
Research Collaboration And License Agreement [Line Items]
Upfront of milestones payment				80,000
Non Early Stage Development Milestones [Member] | Non Exercise of Co-Funding And Co-Promotion Option [Member]
Research Collaboration And License Agreement [Line Items]
Upfront of milestones payment				165,000
Non Early Stage Development Milestones [Member] | Exercise of Co-Funding And Co-Promotion Option [Member]
Research Collaboration And License Agreement [Line Items]
Upfront of milestones payment				70,000
Specified Sales Based Milestones [Member]
Research Collaboration And License Agreement [Line Items]
Upfront of milestones payment				$ 235,000
Pfizer [Member]
Research Collaboration And License Agreement [Line Items]
Upfront payment received	$ 15,000
Research and Development Agreement [Member]
Research Collaboration And License Agreement [Line Items]
Received towards delivery of license and reimbursement of research activities			$ 0		$ 42,000

DARPA Grant Revenue - Additiona

DARPA Grant Revenue - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Apr. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Segment Reporting Revenue Reconciling Item [Line Items]
Allowable costs of reimbursable	$ 5,000
Prepaid expenses and other current assets		$ 4,173		$ 4,173		$ 1,362
DARPA Grant Revenue [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Revenues		400	$ 0	1,100	$ 0
Prepaid expenses and other current assets		$ 200		$ 200		$ 0

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Operating lease, cost		$ 24,000	$ 149,000	$ 72,000	$ 400,000
Operating lease, payments		$ 28,000	$ 153,000	$ 84,000	$ 500,000
Lease term	3 years	3 years		3 years
Annual rent payment	$ 67,000

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Supplemental Balance Sheet Information Related to Leases (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets
Operating lease right-of-use assets	$ 24	$ 92
Total right-of-use assets	24	92
Liabilities
Lease liabilities, current portion	28	108
Operating lease liabilities, non-current	0	0
Total operating lease liabilities	$ 28	$ 108

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Future Minimum Rental Payments for Operating Leases (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Remainder of 2021	$ 28
Total remaining lease payments	28
Less: imputed interest	0
Total operating lease liabilities	28	$ 108
Less: current portion	(28)
Operating lease liabilities, non-current	$ 0	$ 0
Weighted-average discount rate	9.00%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income tax expense	$ 0	$ 5	$ 0	$ 351