SQZ Biotechnologies (SQZB) 10-Q 4 Aug 22 2022 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2022	Jul. 28, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jun. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Entity Registrant Name	SQZ BIOTECHNOLOGIES COMPANY
Entity Central Index Key	0001604477
Entity Incorporation, State or Country Code	DE
Current Fiscal Year End Date	--12-31
Title of 12(b) Security	Common Stock, $0.001 par value per share
Trading Symbol	SQZ
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Shell Company	false
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		29,248,553
Entity Address, State or Province	MA
Entity File Number	001-39662
Entity Tax Identification Number	46-2431115
Entity Address, Address Line One	200 Arsenal Yards Blvd
Entity Address, Address Line Two	Suite 210
Entity Address, City or Town	Watertown
Entity Address, Postal Zip Code	02472
City Area Code	617
Local Phone Number	758-8672

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 105,561	$ 143,513
Accounts receivable		3,000
Prepaid expenses and other current assets	4,491	4,122
Total current assets	110,052	150,635
Property and equipment, net	2,683	3,046
Restricted cash	2,305	2,305
Deferred offering costs	310	323
Operating lease right-of-use assets	64,961	69,843
Total assets	180,311	226,152
Current liabilities:
Accounts payable	1,656	3,971
Accrued expenses	9,711	6,810
Current portion of deferred revenue	6,630	12,507
Current portion of operating lease liabilities	10,446	9,936
Total current liabilities	28,443	33,224
Deferred revenue, net of current portion	9,196	9,196
Operating lease liabilities, net of current portion	54,484	59,756
Total liabilities	92,123	102,176
Commitments and contingencies (Note 8)
Stockholders’ equity:
Preferred stock, $0.001 par value; 10,000,000 shares authorized at June 30, 2022 and December 31, 2021; No shares issued or outstanding.
Common stock, $0.001 par value; 200,000,000 shares authorized at June 30, 2022 and December 31, 2021; 29,148,053 and 28,133,368 shares issued and outstanding at June 30, 2022 and December 31, 2021, respectively.	29	28
Additional paid-in capital	326,943	319,458
Accumulated deficit	(238,784)	(195,510)
Total stockholders’ equity	88,188	123,976
Total liabilities and stockholders’ equity	$ 180,311	$ 226,152

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	29,148,053	28,133,368
Common stock, shares outstanding	29,148,053	28,133,368

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenue Not from Contract with Customer	$ 207		$ 207
Revenues, Total	$ 3,215	$ 4,539	$ 6,084	$ 9,993
Revenue, Product and Service [Extensible Enumeration]	Collaboration [Member]	Collaboration [Member]	Collaboration [Member]	Collaboration [Member]
Operating expenses:
Research and development	$ 18,760	$ 17,682	$ 35,771	$ 32,422
General and administrative	6,958	5,933	13,870	12,054
Total operating expenses	25,718	23,615	49,641	44,476
Loss from operations	(22,503)	(19,076)	(43,557)	(34,483)
Other income (expense):
Interest income	156	11	172	20
Other income (expense), net		(5)	111	(6)
Total other income, net	267	6	283	14
Net loss and comprehensive loss	$ (22,236)	$ (19,070)	$ (43,274)	$ (34,469)
Net loss per share, basic	$ (0.78)	$ (0.68)	$ (1.53)	$ (1.27)
Net loss per share, diluted	$ (0.78)	$ (0.68)	$ (1.53)	$ (1.27)
Weighted-average common shares outstanding, basic	28,367,355	27,919,647	28,256,810	27,100,817
Weighted-average common shares outstanding, diluted	28,367,355	27,919,647	28,256,810	27,100,817
Collaboration [Member]
Revenue	$ 3,008	$ 4,539	$ 5,877	$ 9,993

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Public Offering [Member]	At-the-market Offering [Member]	Common Stock [Member]	Common Stock [Member] Public Offering [Member]	Common Stock [Member] At-the-market Offering [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Public Offering [Member]	Additional Paid-in Capital [Member] At-the-market Offering [Member]	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2020	$ 127,199			$ 25			$ 253,943			$ (126,769)
Beginning balance (Shares) at Dec. 31, 2020				24,786,324
Issuance of common stock		$ 55,602			$ 3			$ 55,599
Issuance of common stock (Shares)					3,000,000
Issuance of common stock upon exercise of stock options	960						960
Issuance of common stock upon exercise of stock options (Shares)				245,080
Stock-based compensation expense	3,412						3,412
Net loss	(34,469)									(34,469)
Ending balance at Jun. 30, 2021	152,704			$ 28			313,914			(161,238)
Ending balance (Shares) at Jun. 30, 2021				28,031,404
Beginning balance at Mar. 31, 2021	169,285			$ 28			311,425			(142,168)
Beginning balance (Shares) at Mar. 31, 2021				27,881,111
Issuance of common stock upon exercise of stock options	660						660
Issuance of common stock upon exercise of stock options (Shares)				150,293
Stock-based compensation expense	1,829						1,829
Net loss	(19,070)									(19,070)
Ending balance at Jun. 30, 2021	152,704			$ 28			313,914			(161,238)
Ending balance (Shares) at Jun. 30, 2021				28,031,404
Beginning balance at Dec. 31, 2021	123,976			$ 28			319,458			(195,510)
Beginning balance (Shares) at Dec. 31, 2021				28,133,368
Issuance of common stock under employee stock purchase plan	111						111
Issuance of common stock under employee stock purchase plan (Shares)				41,265
Issuance of common stock			$ 3,092			$ 1			$ 3,091
Issuance of common stock (Shares)						958,663
Issuance of common stock upon exercise of stock options	$ 29						29
Issuance of common stock upon exercise of stock options (Shares)	14,757			14,757
Stock-based compensation expense	$ 4,254						4,254
Net loss	(43,274)									(43,274)
Ending balance at Jun. 30, 2022	88,188			$ 29			326,943			(238,784)
Ending balance (Shares) at Jun. 30, 2022				29,148,053
Beginning balance at Mar. 31, 2022	104,914			$ 28			321,434			(216,548)
Beginning balance (Shares) at Mar. 31, 2022				28,148,125
Issuance of common stock under employee stock purchase plan	111						111
Issuance of common stock under employee stock purchase plan (Shares)				41,265
Issuance of common stock			$ 3,092			$ 1			$ 3,091
Issuance of common stock (Shares)			958,663
Stock-based compensation expense	2,307						2,307
Net loss	(22,236)									(22,236)
Ending balance at Jun. 30, 2022	$ 88,188			$ 29			$ 326,943			$ (238,784)
Ending balance (Shares) at Jun. 30, 2022				29,148,053

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2022	Jun. 30, 2021
Payment of issuance costs			$ 1,904
Public Offering [Member]
Payment of issuance costs			$ 798
At-the-market Offering [Member]
Payment of issuance costs	$ 192	$ 192

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net loss	$ (43,274)	$ (34,469)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization expense	558	640
Amortization of operating lease right-of-use assets	4,882	4,895
Stock-based compensation expense	4,254	3,412
Loss on disposal of equipment	42	6
Changes in operating assets and liabilities:
Accounts receivable	3,000	1,892
Prepaid expenses and other current assets	(369)	(386)
Accounts payable	(2,278)	(793)
Accrued expenses	2,901	(1,818)
Deferred revenue	(5,877)	(9,767)
Deferred financing costs	13
Operating lease liabilities	(4,762)	(4,609)
Net cash used in operating activities	(40,910)	(40,225)
Cash flows from investing activities:
Purchases of property and equipment	(308)	(521)
Proceeds from disposals of property and equipment	34
Cash flows from investing activities	(274)	(521)
Cash flows from financing activities:
Proceeds from issuance of common stock		56,400
Payment of issuance costs		(1,904)
Proceeds from Issuance of Common Stock		56,400
Proceeds from issuance of common stock under at-the market offering	3,092
Proceeds from issuance of common stock under employee stock purchase plan	111
Proceeds from exercise of stock options	29	960
Net cash provided by financing activities	3,232	55,456
Net (decrease) increase in cash, cash equivalents and restricted cash	(37,952)	14,710
Cash, cash equivalents and restricted cash at beginning of period	145,818	172,662
Cash, cash equivalents and restricted cash at end of period	107,866	$ 187,372
Supplemental disclosure of non-cash investing and financing activities:
Deferred offering costs included in accrued expenses at end of period	$ 106

Nature of the Business and Basi

Nature of the Business and Basis of Presentation	6 Months Ended
	Jun. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business and Basis of Presentation	1. Nature of the Business and Basis of Presentation SQZ Biotechnologies Company (the “Company”) is a clinical-stage biotechnology company developing cell therapies for patients with cancer, autoimmune and infectious diseases and other serious conditions. The Company uses its proprietary Cell Squeeze technology to physically squeeze cells through a microfluidic chip, temporarily opening the cell membrane and enabling biologic material of interest, or cargo, to diffuse into the cell. The Company is using Cell Squeeze technology to create multiple cell therapy platforms focused on directing specific immune responses. The Company was incorporated in March 2013 under the laws of the State of Delaware. The Company is subject to a number of risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, the ability to obtain additional financing, protection of proprietary technology, dependence on key personnel, the ability to attract and retain qualified employees, compliance with government regulations, the impact of the COVID-19 pandemic, and the clinical and commercial success of its product candidates. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s drug development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. The accompanying consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. Since inception, the Company has funded its operations primarily with payments received in connection with collaboration agreements, proceeds from equity and debt financing, and most recently, with proceeds from its 2020 initial public offering (“IPO”) and its 2021 follow-on offering. On November 10, 2021, the Company entered into an Open Market Sales Agreement (the “Sales Agreement”) with Jefferies LLC (“Jefferies”) to issue and sell up to $ 75,000,000 in shares of the Company’s common stock from time to time during the term of the Sales Agreement through an “at-the-market” equity offering program under which Jefferies acts as the Company’s sales agent (the “ATM Facility”). During the three and six months ended June 30, 2022, the Company sold 958,663 shares of common stock under the ATM Facility for net proceeds of approximately $ 3.1 million. The Company has incurred recurring losses since inception, including net losses of $ 43.3 million for the six months ended June 30, 2022. As of June 30, 2022, the Company had an accumulated deficit of $ 238.8 million. The Company expects to continue to generate operating losses for the foreseeable future. As of the issuance date of these interim condensed consolidated financial statements, the Company expects that its cash, cash equivalents and marketable securities will be sufficient to fund its operating expenses and capital expenditure requirements for at least the next 12 months. The Company will seek additional funding through private or public equity financings, debt financings, collaborations, strategic alliances and marketing, distribution or licensing arrangements. The Company may not be able to obtain financing on acceptable terms, or at all, and the Company may not be able to enter into collaborations or other arrangements. The terms of any financing may adversely affect the holdings or the rights of the Company's stockholders. The future viability of the Company is dependent on its ability to raise additional capital to finance its operations. If the Company is unable to obtain funding, the Company will be forced to delay, reduce or eliminate some or all of its research and development programs, product portfolio expansion or commercialization efforts, which could adversely affect its business prospects, or the Company may be unable to continue operations. Although management continues to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all. Impact of the COVID-19 Pandemic In December 2019, a novel strain of coronavirus, which causes the disease known as COVID-19, was initially reported and since then, COVID-19 has spread globally. In March 2020, the World Health Organization declared the COVID-19 outbreak a pandemic and the U.S. government-imposed travel restrictions on travel between the United States, Europe and certain other countries. The outbreak and government measures taken in response have had a significant impact, both direct and indirect, on hospitals, businesses and commerce, as worker shortages have occurred, supply chains have been disrupted, prices have increased and facilities and production have been suspended. The future progression of the pandemic and its effects on the Company’s business and operations are uncertain. The COVID-19 pandemic has impacted and may continue to impact personnel at third-party manufacturing facilities or the availability or cost of materials, which would disrupt the Company’s supply chain. It also has affected and may continue to affect the Company’s ability to enroll patients in and timely complete its ongoing clinical trials of SQZ-PBMC-HPV, SQZ-AAC-HPV and SQZ-eAPC-HPV and delay the initiation of future clinical trials, disrupt regulatory activities or have other adverse effects on its business and operations. The Company is monitoring the potential impact of the COVID-19 pandemic on its business and financial statements. To date, the Company has not incurred impairment losses in the carrying values of its assets as a result of the pandemic and it is not aware of any specific related event or circumstance that would require it to revise its estimates reflected in these interim condensed consolidated financial statements. The extent to which the COVID-19 pandemic will directly or indirectly impact the Company’s business, results of operations, financial condition and liquidity, including planned and future clinical trials and research and development costs, will depend on future developments that are highly uncertain, including as a result of new information that may emerge concerning COVID-19, the actions taken to contain or treat it, and the duration and intensity of the related effects. Basis of Presentation The Company’s consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries, SQZ Biotechnologies Security Corporation, SQZ Biotech HK Limited and SQZ Biotech (Shanghai) Co., Ltd . All intercompany accounts and transactions have been eliminated in consolidation.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Unaudited Interim Financial Information The accompanying condensed consolidated financial statements as of June 30, 2022 and for the three and six months ended June 30, 2022 and 2021 have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial statements. The accompanying condensed consolidated balance sheet as of December 31, 2021 was derived from audited financial statements but does not include all disclosures required by GAAP. Certain information and footnote disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. These interim condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2021 included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2021 filed with the SEC on March 16, 2022. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair statement of the Company’s consolidated financial position as of June 30, 2022, the consolidated results of operations for the three and six months ended June 30, 2022 and 2021, and the consolidated cash flows for the six months ended June 30, 2022 and 2021 have been made. The Company’s consolidated results of operations for the three and six months ended June 30, 2022 are not necessarily indicative of the results of operations that may be expected for the full year or any other subsequent interim period. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of revenue and expenses during the reporting period. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, revenue recognition, the accrual of research and development expenses, the valuation of common stock and the valuation of stock-based awards. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates, judgments and methodologies as there are changes in circumstances, facts and experience. Actual results may differ from those estimates or assumptions. Segment Information The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The Company is developing methods of engineering cell function and therapies for the treatment of patients across a range of indications. The Company has determined that its chief operating decision maker is its Chief Executive Officer. The Company’s chief operating decision maker reviews the Company’s financial information on a consolidated basis for purposes of allocating resources and assessing financial performance. Revenue Recognition for Government Grants The Company generates revenue from government contracts that reimburse the Company for certain allowable costs for funded projects. For contracts with government agencies where the funding arrangement is considered central to the Company’s ongoing operations, the Company classifies the recognized funding received as revenue. Revenue from government grants is recognized as the qualifying expenses related to the contracts are incurred, provided that there is reasonable assurance of recoverability. The Company submits a budget, which outlines the expected project costs, to the funding government agency on a periodic basis. If the government agency approves the project proposed by the Company, the government agency generally funds the project upon receipt of the support for the costs incurred. Revenue recognized upon incurring qualifying expenses in advance of receipt of funding is recorded as unbilled receivables, a component of prepaid expenses and other current assets, in the consolidated balance sheet. The related costs incurred by the Company are included in research and development expense in the Company’s consolidated statements of operations and comprehensive loss. In certain cases, the Company may obtain grants from an economic development agency that are not central to the Company's ongoing business. The income from these grants is recognized within Other income (expense), net in the consolidated statement of operations and comprehensive loss when there is reasonable assurance of recoverability. Recently Issued Accounting Pronouncements The Company qualifies as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 and has elected not to “opt out” of the extended transition related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different application dates for public and nonpublic companies, the Company will adopt the new or revised standard at the time nonpublic companies adopt the new or revised standard and will do so until such time that the Company either (i) irrevocably elects to “opt out” of such extended transition period or (ii) no longer qualifies as an emerging growth company. The Company may choose to early adopt any new or revised accounting standards whenever such early adoption is permitted for nonpublic companies. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”), which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available-for-sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. These changes will result in the earlier recognition of credit losses, if any. In May 2019, the FASB issued ASU No. 2019-05, Financial Instruments—Credit Losses (Topic 326): Targeted Transition Relief (“ASU 2019-05”), which provides additional implementation guidance on the previously issued ASU 2016-13. For the Company, this guidance is effective for fiscal years beginning after December 15, 2022. The Company is currently evaluating the impact that the adoption of ASU 2016-13 will have on its consolidated financial statements, however the Company does not expect that the standard will have a material impact on its consolidated financial statements. In December 2019, the FASB issued ASU No. 2019-12, Simplifying the Accounting for Income Taxes (Topic 740) (“ASU 2019-12”), which simplifies the accounting for income taxes by eliminating certain exceptions, including the approach for intraperiod tax allocation, the accounting for income taxes in an interim period, hybrid taxes and the recognition of deferred tax liabilities for outside basis differences. It also clarifies and simplifies other aspects of the accounting for income taxes. The Company adopted this standard as of January 1, 2022 and the standard did not have a material impact on its consolidated financial statements. In November 2021, the FASB issued ASU 2021-10, Disclosures by Business Entities about Government Assistance, which requires business entities to provide certain disclosures when they have 1) received government assistance and 2) use a grant or contribution accounting model by analogy to other accounting guidance. The Company adopted this standard as of January 1, 2022 and the standard did not have a material impact on its consolidated financial statements.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The following tables present the Company’s fair value hierarchy for its assets and liabilities that are measured at fair value on a recurring basis (in thousands): FAIR VALUE MEASUREMENTS AT LEVEL 1 LEVEL 2 LEVEL 3 TOTAL Assets: Cash equivalents: Money market funds $ 104,215 $ — $ — $ 104,215 $ 104,215 $ — $ — $ 104,215 FAIR VALUE MEASUREMENTS AT LEVEL 1 LEVEL 2 LEVEL 3 TOTAL Assets: Cash equivalents: Money market funds $ 142,547 $ — $ — $ 142,547 $ 142,547 $ — $ — $ 142,547 Money market funds were valued by the Company based on quoted market prices, which represent a Level 1 measurement within the fair value hierarchy. There were no changes to the valuation methods during the six months ended June 30, 2022 .The Company evaluates transfers between levels at the end of each reporting period. There were no transfers between levels during the six months ended June 30, 2022 .

Property and Equipment, Net

Property and Equipment, Net	6 Months Ended
	Jun. 30, 2022
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	4. Property and Equipment, Net Property and equipment, net consisted of the following (in thousands): JUNE 30, DECEMBER 31, 2022 2021 Machinery and equipment $ 6,615 $ 6,659 Leasehold improvements 579 579 Furniture and fixtures 319 319 $ 7,513 $ 7,557 Less: Accumulated depreciation and amortization ( 4,830 ) ( 4,511 ) $ 2,683 $ 3,046 Depreciation and amortization expense for each of the three months ended June 30, 2022 and 2021 was $ 0.3 million. Depreciation and amortization expense for each of the six months ended June 30, 2022 and 2021 was $ 0.6 million.

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2022
Payables and Accruals [Abstract]
Accrued Expenses	5. Accrued Expenses Accrued expenses consisted of the following (in thousands): JUNE 30, DECEMBER 31, 2022 2021 Accrued external research, development and manufacturing costs $ 5,745 $ 2,156 Accrued employee compensation and benefits 2,309 3,040 Other 1,657 1,614 $ 9,711 $ 6,810

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2022
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	6. Stock-Based Compensation The following table summarizes the Company’s stock option activity since December 31, 2021: NUMBER OF WEIGHTED- WEIGHTED- INTRINSIC (in years) (in thousands) Outstanding at December 31, 2021 4,339,523 $ 9.75 7.68 $ 8,823 Granted 2,485,987 5.80 Exercised ( 14,757 ) 1.95 Forfeited or canceled ( 232,215 ) 10.83 Outstanding at June 30, 2022 6,578,538 $ 8.24 7.93 $ 482 Vested and expected to vest at June 30, 2022 6,578,538 $ 8.24 7.93 $ 482 Options exercisable at June 30, 2022 2,608,968 $ 7.74 6.05 $ 482 Stock-Based Compensation Expense Stock-based compensation expense related to stock options was classified in the consolidated statements of operations as follows (in thousands): THREE MONTHS ENDED SIX MONTHS ENDED 2022 2021 2022 2021 Research and development expenses $ 874 $ 683 $ 1,529 $ 1,247 General and administrative expenses 1,433 1,146 2,725 2,165 $ 2,307 $ 1,829 $ 4,254 $ 3,412 As of June 30, 2022 , total unrecognized stock-based compensation expense related to unvested stock-based awards was $ 21.5 million, which is expected to be recognized over a weighted-average period of 2.9 years.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2022
Income Tax Disclosure [Abstract]
Income Taxes	7. Income Taxes For the three and six months ended June 30, 2022 and 2021 , the Company recorded no income tax benefits for the net operating losses incurred or for the research and development tax credits generated in each period, due to its uncertainty of realizing a benefit from those items. Substantially all of the Company’s operating losses since inception have been generated in the United States.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	8. Commitments and Contingencies Leases The Company’s commitments under its leases are described in Note 9. License and Supply Agreements License Agreement with Massachusetts Institute of Technology In December 2015, the Company entered into an exclusive patent license agreement with the Massachusetts Institute of Technology (“MIT”) (the “MIT Agreement”). The MIT Agreement replaced a May 2013 exclusive agreement with MIT. Under the MIT Agreement, the Company received an exclusive license under the licensed patent rights to develop, manufacture and commercialize any products related to certain intracellular delivery methods that were developed at MIT. As of June 30, 2022 and December 31, 2021 , the Company had no liabilities related to the MIT Agreement. During each of the three and six months ended June 30, 2022 and 2021 , the Company did no t recognize any research and development expense under the sublicense terms of the MIT Agreement. Manufacturing Services Agreements The Company has entered into agreements with a contract manufacturing organization to provide manufacturing services related to its product candidates. As of June 30, 2022, the Company had no non-cancelable payments under these agreements, as amended, other than the amounts included in the current portion of operating lease liabilities on the Company's consolidated balance sheets. 401(k) Plan The Company sponsors a 401(k) defined contribution benefit plan (the “401(k) Plan”), which covers all employees who meet certain eligibility requirements as defined in the 401(k) Plan and allows participants to defer a portion of their annual compensation on a pre-tax basis. Contributions to the 401(k) Plan may be made at the discretion of management. For each of the three months ended June 30, 2022 and 2021 , the Company contributed $ 0.1 million to the 401(k) Plan. For each of the six months ended June 30, 2022 and 2021 , the Company contributed $ 0.2 million to the 401(k) Plan. Indemnification Agreements In the ordinary course of business, the Company may provide indemnification of varying scope and terms to its vendors, lessors, contract research organizations, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with its executive officers and members of its board of directors that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. The Company has not incurred any material costs as a result of such indemnification agreements and is not currently aware of any indemnification claims. Legal Proceedings The Company is not currently party to any material legal proceedings. At each reporting date, the Company evaluates whether or not a potential loss amount or a potential range of loss is probable and reasonably estimable under the provisions of the authoritative guidance that addresses accounting for contingencies. The Company expenses as incurred the costs related to such legal proceedings.

Leases

Leases	6 Months Ended
	Jun. 30, 2022
Leases [Abstract]
Leases	9. Leases As of June 30, 2022, the Company leases its office and laboratory facilities under a non-cancelable operating lease entered into in December 2018, which included lease incentives, payment escalations and rent holidays. In addition, the Company has an agreement entered into in April 2019 with a contract manufacturing supplier that is considered an embedded lease because the Company has substantially all the economic benefits of the related asset and can direct its use. The Company had not entered into any financing leases or any short-term operating leases as of June 30, 2022 and December 31, 2021. The components of lease cost and other information for the Company’s lease portfolio were as follows (in thousands, except term and discount rate amounts): THREE MONTHS ENDED SIX MONTHS ENDED 2022 2021 2022 2021 Lease cost: Operating lease cost $ 3,760 $ 3,273 $ 7,520 $ 6,534 Variable lease cost 414 679 970 1,003 $ 4,174 $ 3,952 $ 8,490 $ 7,537 JUNE 30, DECEMBER 31, Other information: Weighted-average remaining lease term (in years) 5.7 6.2 Weighted-average discount rate 7.6 % 7.6 % Supplemental cash flow information related to the Company’s operating leases was as follows (in thousands): SIX MONTHS ENDED JUNE 30, 2022 2021 Cash paid for amounts included in the measurement of operating lease liabilities: Operating cash flows from operating leases $ 7,403 $ 6,249

License and Collaboration Agree

License and Collaboration Agreements	6 Months Ended
	Jun. 30, 2022
Research and Development [Abstract]
License and Collaboration Agreements	10. License and Collaboration Agreements 2017 License and Collaboration Agreement with Roche In April 2017, the Company entered into a second license and collaboration agreement with Roche (the “2017 Roche Agreement”) to allow Roche to use the Company’s Cell Squeeze technology to enable gene editing of immune cells to discover new targets in cancer immunotherapy. The 2017 Roche Agreement included several licenses granted by Roche to the Company and by the Company to Roche in order to conduct a specified research program in accordance with a specified research plan. In the first quarter of 2022, the 2017 Roche Agreement was terminated and all active work streams under the 2017 Roche Agreement were concluded. As of December 31, 2021, the Company determined that it expected to incur no additional costs to satisfy the remaining performance obligations under the 2017 Roche Agreement and all remaining deferred revenue was recognized as of that date. There was no revenue recorded under this agreement during the three and six months ended June 30, 2022. During the three and six months ended June 30, 2021, the total costs expected to be incurred to satisfy the performance obligation under the 2017 Roche Agreement decreased by $ 0.1 million and $ 0.3 million, respectively. The Company recognized revenue of $ 0.2 million and $ 0.8 million during the three and six months ended June 30, 2021, respectively. 2018 License and Collaboration Agreement with Roche In October 2018, the Company entered into a license and collaboration agreement with Roche (the “2018 Roche Agreement”) to jointly develop certain products based on mononuclear antigen presenting cells (“APCs”), including human papillomavirus (“HPV”), using the SQZ APC platform for the treatment of oncology indications. The Company granted Roche a non-exclusive license to its intellectual property, and Roche granted the Company a non-exclusive license to its and its affiliates’ intellectual property for the purpose of performing research activities. In connection with this agreement, the parties terminated an earlier agreement. The 2018 Roche Agreement has a term that extends until all royalty, profit-share and other payment obligations expire or have been satisfied. Roche has the right to terminate the 2018 Roche Agreement, in whole or on a product-by-product basis, upon a specified amount of notice to the Company. The Company or Roche may terminate the agreement if the other party fails to cure its material breach within a specified period after receiving notice of such breach. Under the 2018 Roche Agreement, Roche was granted option rights to obtain an exclusive license to develop APC products or products derived from the collaboration programs on a product-by-product basis. These option rights are exercisable upon the achievement of clinical Phase 1 proof of concept and expire, if unexercised, as of a date specified in the agreement. In addition, Roche was granted an option right to obtain an exclusive license to develop a Tumor Cell Lysate (“TCL”) product. This option right is exercisable upon the achievement of clinical proof of concept and expires, if unexercised, as of a date specified in the agreement. For each of the APC products and TCL product, once Roche exercises its option and pays a specified incremental amount ranging from $ 15.0 million to $ 50.0 million for APC products and of $ 100.0 million for the TCL product, Roche will receive worldwide, exclusive commercialization rights for the licensed products, subject to the Company’s alternating option to retain U.S. APC commercialization rights. The Company will retain worldwide commercialization rights to any APC products or the TCL product for which Roche elects not to exercise its applicable option. For the first APC product that Roche exercises its option, Roche will receive worldwide, exclusive commercialization rights for the licensed product. On a product-by-product basis for the APC products, after the first product option is exercised by Roche and for every other product for which Roche exercises its option, the Company will retain an option to obtain the exclusive commercialization rights in the United States. Upon exercise of the TCL option by Roche, (i) the Company will be entitled to receive the aforementioned milestone payment of $ 100.0 million and (ii) profits from the TCL product will be shared equally by the Company and Roche. Through June 30, 2022, Roche had not exercised any of its options under the 2018 Roche Agreement. Under the 2018 Roche Agreement, the Company received an upfront payment of $ 45.0 million and is eligible to receive (i) reimbursement of a mid-double-digit percentage of its development costs; (ii) aggregate milestone payments on a product-by-product basis of up to $ 1.6 billion upon the achievement of specified milestones, consisting of up to $ 217.0 million of development milestone payments, up to $ 240.0 million of regulatory milestone payments and up to $ 1.2 billion of sales milestone payments; and (iii) tiered royalties on annual net sales of APC and TCL products licensed under the agreement, as described below. The Company received the upfront payment of $ 45.0 million in October 2018 upon execution of the agreement. In addition, during the second quarter of 2019, the Company received a payment of $ 10.0 million following the achievement of the first development milestone under the 2018 Roche Agreement related to submission by the Company of preclinical data to the U.S. Food and Drug Administration (“FDA”). During the first quarter of 2020, the Company received a payment of $ 20.0 million following the achievement of the second development milestone under the 2018 Roche Agreement related to first-patient dosing in a Phase 1 clinical trial. In the first quarter of 2022, the Company received a milestone payment of $ 3.0 million having achieved in the fourth quarter of 2021 the following: (i) the endorsement by an independent panel that it could advance its SQZ-PBMC-HPV clinical trial to combination therapy using checkpoint inhibitors and (ii) the initiation of that therapy. Roche will pay tiered royalties based on annual net sales of APC and TCL products. If Roche exercises its option to obtain a license to commercialize an APC product, Roche will pay the Company tiered royalties on annual net sales of that licensed product at rates ranging from a mid-single-digit percentage to a mid-teens percentage, depending on net sales of the product. If the Company exercises its option to obtain a license to commercialize an APC product in the United States, it will pay Roche tiered royalties on annual net sales of that licensed product at rates ranging from a mid-single-digit percentage to a mid-teens percentage, depending on net sales of the product in the United States. For APC products selected by Roche, rather than mutually, Roche will pay the Company royalties on annual net sales of that licensed product at rates ranging from a mid-single-digit percentage to a high single-digit percentage, depending on net sales of the product. For APC products that are selected mutually and for which the Company has not exercised its option to commercialize the product in the United States, Roche will pay the Company tiered royalties on annual net sales of that licensed product at a rate ranging from a high single-digit percentage to a mid-teens percentage, depending on net sales of the product. For TCL products, Roche will pay the Company tiered royalties on the aggregate net sales of all TCL products at rates ranging from either a mid-single digit percentage to a percentage in the low twenties, with the caveat that the rates for sales in the United States may instead range from a low-teens percentage to a percentage in the mid-twenties, depending on whether and when the Company opts out of sharing certain profits and costs of commercializing the TCL product in the United States with Roche. The Company identified three performance obligations at the outset of the 2018 Roche Agreement: (1) the license to the Company’s intellectual property, the research and development activities related to HPV through Phase 1 clinical trials under a specified research plan, and the manufacturing of the Company’s SQZ APC platform and equipment in order to support the HPV research plan (the “first performance obligation”); (2) the license to the Company’s intellectual property and the research and development activities on next-generation APCs (the “second performance obligation”); and (3) the license to the Company’s intellectual property and the research and development activities on TCL (the “third performance obligation”). During the fourth quarter of 2019, the Company evaluated its overall program priorities and determined that it would continue to focus its resources on progressing the specified APC programs related to the 2018 Roche Agreement as well as its Activating Antigen Carriers (“AAC”) and Tolerizing Antigen Carriers (“TAC”) platforms. As a result of its continuing focus on these specific programs, the Company reduced the level of priority of the TCL research activities under the 2018 Roche Agreement and expects to perform such TCL research activities over a longer time period than as originally expected under the specified research plan of the agreement. Since the fourth quarter of 2019, the Company has classified $ 9.2 million as non-current deferred revenue, which will remain unrecognized as revenue until TCL research activities resume or the 2018 Roche Agreement is modified by the Company and Roche. The Company separately recognizes revenue associated with each of the three performance obligations as the research, development and manufacturing services are provided using an input method, based on the cumulative costs incurred compared to the total estimated costs expected to be incurred to satisfy each performance obligation. The transfer of control to the customer occurs over the time period that the research and development services are to be provided by the Company, and this cost-to-cost method is, in management’s judgment, the best measure of progress towards satisfying each performance obligation. The amounts received that have not yet been recognized as revenue are deferred as a contract liability in the Company’s consolidated balance sheet and will be recognized over the remaining research and development period until each performance obligation is satisfied. During the three and six months ended June 30, 2022 and 2021 , there were no significant changes in the total estimated costs expected to be incurred to satisfy the performance obligations under the 2018 Roche Agreement. The Company recognized revenue of $ 3.0 million and $ 4.3 million during the three months ended June 30, 2022 and 2021 , respectively, under this agreement. The Company recognized revenue of $ 5.9 million and $ 9.1 million during the six months ended June 30, 2022 and 2021, respectively, under this agreement. As of June 30, 2022, the Company recorded as a contract liability deferred revenue related to the 2018 Roche Agreement of $ 15.3 million, of which $ 6.1 million was a current liability. As of June 30, 2022 , the research and development services related to the performance obligations were expected to be performed over a remaining period of six months . As of December 31, 2021, the Company recorded as a contract liability deferred revenue related to the 2018 Roche Agreement of $ 21.2 million, of which $ 12.0 million was a current liability. As of June 30, 2022 and December 31, 2021, the expected remaining period of performance of the Company’s research and development services related to the third performance obligation was not determinable, and it will not become determinable until TCL research activities resume or the 2018 Roche Agreement is modified by the Company and Roche. Contract Liability The changes in the total contract liability (deferred revenue) balances related to the Company’s license and collaboration agreements were as follows (in thousands): THREE MONTHS ENDED SIX MONTHS ENDED JUNE 30, 2022 2021 2022 2021 Balance at beginning of period $ 18,334 $ 39,747 $ 21,203 $ 45,201 Recognition of deferred revenue ( 3,008 ) ( 4,539 ) ( 5,877 ) ( 9,993 ) Other — 100 — 100 Balance at end of period $ 15,326 $ 35,308 $ 15,326 $ 35,308

Net Loss per Share

Net Loss per Share	6 Months Ended
	Jun. 30, 2022
Earnings Per Share [Abstract]
Net Loss per Share	11. Net Loss per Share Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share amounts): THREE MONTHS ENDED SIX MONTHS ENDED 2022 2021 2022 2021 Numerator: Net loss $ ( 22,236 ) $ ( 19,070 ) $ ( 43,274 ) $ ( 34,469 ) Denominator: Weighted-average common shares outstanding, basic and 28,367,355 27,919,647 28,256,810 27,100,817 Net loss per share attributable to common stockholders, basic and $ ( 0.78 ) $ ( 0.68 ) $ ( 1.53 ) $ ( 1.27 ) The Company’s potential dilutive securities, which consist of common stock options have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted-average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: THREE MONTHS ENDED SIX MONTHS ENDED JUNE 30, 2022 2021 2022 2021 Stock options to purchase common stock 6,578,538 4,571,645 6,578,538 4,571,645 6,578,538 4,571,645 6,578,538 4,571,645

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying condensed consolidated financial statements as of June 30, 2022 and for the three and six months ended June 30, 2022 and 2021 have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial statements. The accompanying condensed consolidated balance sheet as of December 31, 2021 was derived from audited financial statements but does not include all disclosures required by GAAP. Certain information and footnote disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. These interim condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2021 included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2021 filed with the SEC on March 16, 2022. In the opinion of management, all adjustments, consisting only of normal recurring adjustments necessary for a fair statement of the Company’s consolidated financial position as of June 30, 2022, the consolidated results of operations for the three and six months ended June 30, 2022 and 2021, and the consolidated cash flows for the six months ended June 30, 2022 and 2021 have been made. The Company’s consolidated results of operations for the three and six months ended June 30, 2022 are not necessarily indicative of the results of operations that may be expected for the full year or any other subsequent interim period.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of revenue and expenses during the reporting period. Significant estimates and assumptions reflected in these condensed consolidated financial statements include, but are not limited to, revenue recognition, the accrual of research and development expenses, the valuation of common stock and the valuation of stock-based awards. The Company bases its estimates on historical experience, known trends and other market-specific or other relevant factors that it believes to be reasonable under the circumstances. On an ongoing basis, management evaluates its estimates, judgments and methodologies as there are changes in circumstances, facts and experience. Actual results may differ from those estimates or assumptions.
Segment Information	Segment Information The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. The Company is developing methods of engineering cell function and therapies for the treatment of patients across a range of indications. The Company has determined that its chief operating decision maker is its Chief Executive Officer. The Company’s chief operating decision maker reviews the Company’s financial information on a consolidated basis for purposes of allocating resources and assessing financial performance.
Revenue Recognition for Government Grants	Revenue Recognition for Government Grants The Company generates revenue from government contracts that reimburse the Company for certain allowable costs for funded projects. For contracts with government agencies where the funding arrangement is considered central to the Company’s ongoing operations, the Company classifies the recognized funding received as revenue. Revenue from government grants is recognized as the qualifying expenses related to the contracts are incurred, provided that there is reasonable assurance of recoverability. The Company submits a budget, which outlines the expected project costs, to the funding government agency on a periodic basis. If the government agency approves the project proposed by the Company, the government agency generally funds the project upon receipt of the support for the costs incurred. Revenue recognized upon incurring qualifying expenses in advance of receipt of funding is recorded as unbilled receivables, a component of prepaid expenses and other current assets, in the consolidated balance sheet. The related costs incurred by the Company are included in research and development expense in the Company’s consolidated statements of operations and comprehensive loss. In certain cases, the Company may obtain grants from an economic development agency that are not central to the Company's ongoing business. The income from these grants is recognized within Other income (expense), net in the consolidated statement of operations and comprehensive loss when there is reasonable assurance of recoverability.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements The Company qualifies as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 and has elected not to “opt out” of the extended transition related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different application dates for public and nonpublic companies, the Company will adopt the new or revised standard at the time nonpublic companies adopt the new or revised standard and will do so until such time that the Company either (i) irrevocably elects to “opt out” of such extended transition period or (ii) no longer qualifies as an emerging growth company. The Company may choose to early adopt any new or revised accounting standards whenever such early adoption is permitted for nonpublic companies. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”), which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss model. It also eliminates the concept of other-than-temporary impairment and requires credit losses related to available-for-sale debt securities to be recorded through an allowance for credit losses rather than as a reduction in the amortized cost basis of the securities. These changes will result in the earlier recognition of credit losses, if any. In May 2019, the FASB issued ASU No. 2019-05, Financial Instruments—Credit Losses (Topic 326): Targeted Transition Relief (“ASU 2019-05”), which provides additional implementation guidance on the previously issued ASU 2016-13. For the Company, this guidance is effective for fiscal years beginning after December 15, 2022. The Company is currently evaluating the impact that the adoption of ASU 2016-13 will have on its consolidated financial statements, however the Company does not expect that the standard will have a material impact on its consolidated financial statements. In December 2019, the FASB issued ASU No. 2019-12, Simplifying the Accounting for Income Taxes (Topic 740) (“ASU 2019-12”), which simplifies the accounting for income taxes by eliminating certain exceptions, including the approach for intraperiod tax allocation, the accounting for income taxes in an interim period, hybrid taxes and the recognition of deferred tax liabilities for outside basis differences. It also clarifies and simplifies other aspects of the accounting for income taxes. The Company adopted this standard as of January 1, 2022 and the standard did not have a material impact on its consolidated financial statements. In November 2021, the FASB issued ASU 2021-10, Disclosures by Business Entities about Government Assistance, which requires business entities to provide certain disclosures when they have 1) received government assistance and 2) use a grant or contribution accounting model by analogy to other accounting guidance. The Company adopted this standard as of January 1, 2022 and the standard did not have a material impact on its consolidated financial statements.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2022
Fair Value Disclosures [Abstract]
Summary of fair value hierarchy for assets and liabilities	The following tables present the Company’s fair value hierarchy for its assets and liabilities that are measured at fair value on a recurring basis (in thousands): FAIR VALUE MEASUREMENTS AT LEVEL 1 LEVEL 2 LEVEL 3 TOTAL Assets: Cash equivalents: Money market funds $ 104,215 $ — $ — $ 104,215 $ 104,215 $ — $ — $ 104,215 FAIR VALUE MEASUREMENTS AT LEVEL 1 LEVEL 2 LEVEL 3 TOTAL Assets: Cash equivalents: Money market funds $ 142,547 $ — $ — $ 142,547 $ 142,547 $ — $ — $ 142,547

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	6 Months Ended
	Jun. 30, 2022
Property, Plant and Equipment, Net [Abstract]
Summary of property and equipment, net	Property and equipment, net consisted of the following (in thousands): JUNE 30, DECEMBER 31, 2022 2021 Machinery and equipment $ 6,615 $ 6,659 Leasehold improvements 579 579 Furniture and fixtures 319 319 $ 7,513 $ 7,557 Less: Accumulated depreciation and amortization ( 4,830 ) ( 4,511 ) $ 2,683 $ 3,046

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2022
Payables and Accruals [Abstract]
Summary of accrued expenses	Accrued expenses consisted of the following (in thousands): JUNE 30, DECEMBER 31, 2022 2021 Accrued external research, development and manufacturing costs $ 5,745 $ 2,156 Accrued employee compensation and benefits 2,309 3,040 Other 1,657 1,614 $ 9,711 $ 6,810

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2022
Share-Based Payment Arrangement [Abstract]
Summary of Stock Option Activity	The following table summarizes the Company’s stock option activity since December 31, 2021: NUMBER OF WEIGHTED- WEIGHTED- INTRINSIC (in years) (in thousands) Outstanding at December 31, 2021 4,339,523 $ 9.75 7.68 $ 8,823 Granted 2,485,987 5.80 Exercised ( 14,757 ) 1.95 Forfeited or canceled ( 232,215 ) 10.83 Outstanding at June 30, 2022 6,578,538 $ 8.24 7.93 $ 482 Vested and expected to vest at June 30, 2022 6,578,538 $ 8.24 7.93 $ 482 Options exercisable at June 30, 2022 2,608,968 $ 7.74 6.05 $ 482
Summary of Stock-Based Compensation Expense	Stock-based compensation expense related to stock options was classified in the consolidated statements of operations as follows (in thousands): THREE MONTHS ENDED SIX MONTHS ENDED 2022 2021 2022 2021 Research and development expenses $ 874 $ 683 $ 1,529 $ 1,247 General and administrative expenses 1,433 1,146 2,725 2,165 $ 2,307 $ 1,829 $ 4,254 $ 3,412

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2022
Leases [Abstract]
Summary of Components of Lease Cost and Other Information	The components of lease cost and other information for the Company’s lease portfolio were as follows (in thousands, except term and discount rate amounts): THREE MONTHS ENDED SIX MONTHS ENDED 2022 2021 2022 2021 Lease cost: Operating lease cost $ 3,760 $ 3,273 $ 7,520 $ 6,534 Variable lease cost 414 679 970 1,003 $ 4,174 $ 3,952 $ 8,490 $ 7,537 JUNE 30, DECEMBER 31, Other information: Weighted-average remaining lease term (in years) 5.7 6.2 Weighted-average discount rate 7.6 % 7.6 %
Summary of Supplementary Cash Flow Information Relating to Operating Leases	Supplemental cash flow information related to the Company’s operating leases was as follows (in thousands): SIX MONTHS ENDED JUNE 30, 2022 2021 Cash paid for amounts included in the measurement of operating lease liabilities: Operating cash flows from operating leases $ 7,403 $ 6,249

License and Collaboration Agr_2

License and Collaboration Agreements (Tables)	6 Months Ended
	Jun. 30, 2022
Research and Development [Abstract]
Summary of Changes in the Total Contract Liability	The changes in the total contract liability (deferred revenue) balances related to the Company’s license and collaboration agreements were as follows (in thousands): THREE MONTHS ENDED SIX MONTHS ENDED JUNE 30, 2022 2021 2022 2021 Balance at beginning of period $ 18,334 $ 39,747 $ 21,203 $ 45,201 Recognition of deferred revenue ( 3,008 ) ( 4,539 ) ( 5,877 ) ( 9,993 ) Other — 100 — 100 Balance at end of period $ 15,326 $ 35,308 $ 15,326 $ 35,308

Net Loss per Share (Tables)

Net Loss per Share (Tables)	6 Months Ended
	Jun. 30, 2022
Earnings Per Share [Abstract]
Summary of basic and diluted net loss per share attributable to common stockholders	Basic and diluted net loss per share attributable to common stockholders was calculated as follows (in thousands, except share and per share amounts): THREE MONTHS ENDED SIX MONTHS ENDED 2022 2021 2022 2021 Numerator: Net loss $ ( 22,236 ) $ ( 19,070 ) $ ( 43,274 ) $ ( 34,469 ) Denominator: Weighted-average common shares outstanding, basic and 28,367,355 27,919,647 28,256,810 27,100,817 Net loss per share attributable to common stockholders, basic and $ ( 0.78 ) $ ( 0.68 ) $ ( 1.53 ) $ ( 1.27 )
Summary of potentially dilutive shares excluded from the calculation of diluted net loss	The Company’s potential dilutive securities, which consist of common stock options have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted-average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect: THREE MONTHS ENDED SIX MONTHS ENDED JUNE 30, 2022 2021 2022 2021 Stock options to purchase common stock 6,578,538 4,571,645 6,578,538 4,571,645 6,578,538 4,571,645 6,578,538 4,571,645

Nature of the Business and Ba_2

Nature of the Business and Basis of Presentation - Additional Information (Detail) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Proceeds from issuance of common stock under at-the market offering		$ 3,092,000
Income (loss) from continuing operations		(43,300,000)
Accumulated deficit	$ 238,784,000	$ 238,784,000	$ 195,510,000
Follow-on Offering [Member]
Number of shares sold at-the-market offering facility	958,663	958,663
Proceeds from follow on public offer net of underwriting discounts and before payment of offering costs	$ 3,100,000	$ 3,100,000
Follow-on Offering [Member] | Maximum [Member]
Proceeds from issuance of common stock under at-the market offering		$ 75,000,000

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Fair Value Hierarchy for Assets and Liabilities (Detail) - Fair Value, Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Assets:
Assets, fair value disclosure	$ 104,215	$ 142,547
Level 1 [Member]
Assets:
Assets, fair value disclosure	104,215	142,547
Money Market Funds [Member] | Cash equivalents [Member]
Assets:
Assets, fair value disclosure	104,215	142,547
Money Market Funds [Member] | Cash equivalents [Member] | Level 1 [Member]
Assets:
Assets, fair value disclosure	$ 104,215	$ 142,547

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details)	Jun. 30, 2022 USD ($)
Fair Value Disclosures [Abstract]
Fair value, assets, level 1 to level 2 transfers, amount	$ 0
Fair value, assets, level 2 to level 1 transfers, amount	0
Fair value, liabilities, level 1 to level 2 transfers, amount	0
Fair value, liabilities, level 2 to level 1 transfers, amount	0
Fair value, assets, level 1 to level 3 transfers, amount	0
Fair value, assets, level 2 to level 3 transfers, amount	0
Fair value, assets, level 3 to level 1 transfers, amount	0
Fair value, assets, level 3 to level 2 transfers, amount	0
Fair value, liabilities, level 1 to level 3 transfers, amount	0
Fair value, liabilities, level 2 to level 3 transfers, amount	0
Fair value, liabilities, level 3 to level 1 transfers, amount	0
Fair value, liabilities, level 3 to level 2 transfers, amount	$ 0

Property and Equipment, Net - S

Property and Equipment, Net - Summary of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Property, Plant and Equipment, Net [Abstract]
Machinery and equipment	$ 6,615	$ 6,659
Leasehold improvements	579	579
Furniture and fixtures	319	319
Total property and equipment, gross	7,513	7,557
Less: Accumulated depreciation and amortization	(4,830)	(4,511)
Total property and equipment, net	$ 2,683	$ 3,046

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 300	$ 300	$ 558	$ 640

Accrued Expenses - Summary of A

Accrued Expenses - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued external research, development and manufacturing costs	$ 5,745	$ 2,156
Accrued employee compensation and benefits	2,309	3,040
Other	1,657	1,614
Total accrued expenses	$ 9,711	$ 6,810

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2022 USD ($)
Stockbased Compensation [Line Items]
Unrecognized compensation expense related to unvested stock based awards	$ 21.5
Unrecognized compensation expense expected period for recognition	2 years 10 months 24 days

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Number of Shares - Outstanding at December 31, 2021	4,339,523
Granted	2,485,987
Exercised	(14,757)
Forfeited or canceled	(232,215)
Number of Shares - Outstanding at March 31, 2022	6,578,538	4,339,523
Number of Shares - Vested and expected to vest at March 31, 2022	6,578,538
Number of Shares - Options exercisable at March 31, 2022	2,608,968
Weighted Average Exercise Price - Outstanding at December 31, 2021	$ 9.75
Granted	5.80
Exercised	1.95
Forfeited or canceled	10.83
Weighted Average Exercise Price - Outstanding at March 31, 2022	8.24	$ 9.75
Weighted Average Exercise Price - Vested and expected to vest at March 31, 2022	8.24
Weighted Average Exercise Price - Options exercisable at March 31, 2022	$ 7.74
Weighted-Average Remaining Contractual Term	7 years 11 months 4 days	7 years 8 months 4 days
Weighted-Average Remaining Contractual Term - Vested and expected to vest	7 years 11 months 4 days
Weighted-Average Remaining Contractual Term - Options exercisable	6 years 18 days
Aggregate Intrinsic Value - Outstanding	$ 482	$ 8,823
Aggregate Intrinsic Value - Vested and expected to vest	482
Aggregate Intrinsic Value - Options exercisable	$ 482

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 2,307	$ 1,829	$ 4,254	$ 3,412
Research and Development Expense [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	874	683	1,529	1,247
General and Administrative Expense [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 1,433	$ 1,146	$ 2,725	$ 2,165

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Tax Disclosure [Abstract]
Income tax benefits	$ 0	$ 0	$ 0	$ 0

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Other Commitments [Line Items]
Commitments and contingencies (Note 8)
Research and development	18,760,000	$ 17,682,000	35,771,000	$ 32,422,000
Discretionary contribution by the employer to defined contribution benefit plan	100,000	100,000	200,000	200,000
Manufacturing Services Agreements [Member]
Other Commitments [Line Items]
Non-cancelable payments	0		0
Sublicense Agreement [Member]
Other Commitments [Line Items]
Research and development	0	$ 0	0	$ 0
Massachusetts Institute Of Technology
Other Commitments [Line Items]
Commitments and contingencies (Note 8)	$ 0		$ 0		$ 0

Leases - Summary of Components

Leases - Summary of Components of Lease Cost and Other Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Lease cost:
Operating lease cost	$ 3,760	$ 3,273	$ 7,520	$ 6,534
Variable lease cost	414	679	970	1,003
Lease Cost	$ 4,174	$ 3,952	$ 8,490	$ 7,537
Other information:
Weighted-average remaining lease term (in years)	5 years 8 months 12 days		5 years 8 months 12 days		6 years 2 months 12 days
Weighted-average discount rate	7.60%		7.60%		7.60%

Leases - Summary of Supplementa

Leases - Summary of Supplementary Cash Flow Information Relating to Operating Leases (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Leases [Abstract]
Operating cash flows from operating leases	$ 7,403	$ 6,249

License and Collaboration Agr_3

License and Collaboration Agreements - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended						6 Months Ended
	Oct. 31, 2018	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
License And Collaboration Agreements [Line Items]
Contract with customer liability revenue recognized		$ 3,008,000		$ 4,539,000				$ 5,877,000	$ 9,993,000
Contract with customer liability		15,326,000	$ 18,334,000	35,308,000				15,326,000	35,308,000	$ 21,203,000	$ 39,747,000	$ 45,201,000
2017 License and Collaboration Agreement With Roche [Member] | Roche [Member]
License And Collaboration Agreements [Line Items]
Estimated costs to be incurred to satisfy performance obligation				100,000					300
Contract with customer liability revenue recognized		0		200				0	800,000
2018 License and Collaboration Agreement With Roche [Member]
License And Collaboration Agreements [Line Items]
Milestone payment receivable on exercise of option rights		100,000,000						100,000,000
2018 License and Collaboration Agreement With Roche [Member] | Roche [Member]
License And Collaboration Agreements [Line Items]
Upfront payment received towards technology access fee	$ 45,000,000
Estimated costs to be incurred to satisfy performance obligation		0		0				0	0
Contract with customer liability current			6,100,000							12,000,000
Milestone payment receivable based on product		1,600,000						1,600,000
Milestone payment received			$ 3,000
Performance obligation revenue recognized		3,000,000		$ 4,300,000				5,900,000	$ 9,100,000
Contract with customer liability		15,300,000						15,300,000		$ 21,200,000
2018 License and Collaboration Agreement With Roche [Member] | Roche [Member] | Development Milestone [Member]
License And Collaboration Agreements [Line Items]
Milestone payment receivable based on product		217,000,000						217,000,000
2018 License and Collaboration Agreement With Roche [Member] | Roche [Member] | Development Milestone [Member] | First Patient Doosing Phase One Clinical Trial [Member]
License And Collaboration Agreements [Line Items]
Milestone payment received					$ 20,000,000
2018 License and Collaboration Agreement With Roche [Member] | Roche [Member] | Regulatory Milestone [Member]
License And Collaboration Agreements [Line Items]
Milestone payment receivable based on product		240,000,000						240,000,000
2018 License and Collaboration Agreement With Roche [Member] | Roche [Member] | Regulatory Milestone [Member] | Preclinical Data Submitted To FDA For Approval [Member]
License And Collaboration Agreements [Line Items]
Milestone payment received							$ 10,000,000
2018 License and Collaboration Agreement With Roche [Member] | Roche [Member] | Sales Milestone [Member]
License And Collaboration Agreements [Line Items]
Milestone payment receivable based on product		1,200,000,000						1,200,000,000
2018 License and Collaboration Agreement With Roche [Member] | Roche [Member] | APC [Member]
License And Collaboration Agreements [Line Items]
Amount payable on exercise of option rights to use the license		15,000,000						15,000,000
2018 License and Collaboration Agreement With Roche [Member] | Roche [Member] | TCL [Member]
License And Collaboration Agreements [Line Items]
Contract liabilities current reclassified to non current						$ 9,200,000
2018 License and Collaboration Agreement With Roche [Member] | Roche [Member] | Maximum [Member] | TCL [Member]
License And Collaboration Agreements [Line Items]
Amount payable on exercise of option rights to use the license		100,000,000						100,000,000
2018 License and Collaboration Agreement With Roche [Member] | Roche [Member] | Minimum [Member] | TCL [Member]
License And Collaboration Agreements [Line Items]
Amount payable on exercise of option rights to use the license		$ 50,000,000						$ 50,000,000

License and Collaboration Agr_4

License and Collaboration Agreements - Additional Information (Detail1)	Jun. 30, 2022
2018 License and Collaboration Agreement With Roche [Member] | Roche [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-07-01
License And Collaboration Agreements [Line Items]
Remaining period over which the performance obligation is to be satisfied	6 months

License and Collaboration Agr_5

License and Collaboration Agreements - Summary of Changes in the Total Contract Liability (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Research and Development [Abstract]
Balance at beginning of period	$ 18,334	$ 39,747	$ 21,203	$ 45,201
Recognition of deferred revenue	(3,008)	(4,539)	(5,877)	(9,993)
Other		100		100
Balance at end of period	$ 15,326	$ 35,308	$ 15,326	$ 35,308

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of basic and diluted net loss per share attributable to common stockholders (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share [Abstract]
Net loss	$ (22,236)	$ (19,070)	$ (43,274)	$ (34,469)
Weighted-average common shares outstanding, basic	28,367,355	27,919,647	28,256,810	27,100,817
Weighted-average common shares outstanding, diluted	28,367,355	27,919,647	28,256,810	27,100,817
Net loss per share attributable to common stockholders, basic	$ (0.78)	$ (0.68)	$ (1.53)	$ (1.27)
Net loss per share attributable to common stockholders, diluted	$ (0.78)	$ (0.68)	$ (1.53)	$ (1.27)

Net Loss Per Share - Summary _2

Net Loss Per Share - Summary of potentially dilutive shares excluded from the calculation of diluted net loss (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	6,578,538	4,571,645	6,578,538	4,571,645
Share-based Payment Arrangement, Option [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	6,578,538	4,571,645	6,578,538	4,571,645