0000950170-21-002534 | 10-Q | XBRL Viewer

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Document And Entity Information - shares	9 Months Ended
Document And Entity Information - shares	Sep. 30, 2021	Oct. 29, 2021
Cover [Abstract]
Entity Registrant Name	KALEIDO BIOSCIENCES, INC.
Document Type	10-Q
Amendment Flag	false
Trading Symbol	KLDO
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		42,594,350
Entity Central Index Key	0001751299
Entity Filer Category	Non-accelerated Filer
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Security Exchange Name	NASDAQ
Entity File Number	001-38822
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-3048279
Entity Address, Address Line One	65 Hayden Avenue
Entity Address, City or Town	Lexington
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02421
City Area Code	617
Local Phone Number	674-9000
Document Quarterly Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock, $0.001 Par Value
Entity Ex Transition Period	false

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 55,657	$ 46,222
Prepaid expenses and other current assets	2,647	2,499
Total current assets	58,304	48,721
Property and equipment, net	7,339	8,462
Restricted cash	2,161	2,161
Total assets	67,804	59,344
Current liabilities:
Accounts payable	3,559	5,389
Accrued expenses and other current liabilities	9,318	8,636
Current term debt, net of unamortized debt discount	6,384	2,634
Total current liabilities	19,261	16,659
Long-term Debt, Excluding Current Maturities, Total	15,132	18,375
Other liabilities	4,211	3,814
Total liabilities	38,604	38,848
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, $0.001 par value, 10,000,000 authorized; no shares issued or outstanding
Common stock, $0.001 par value, 150,000,000 shares authorized; 42,580,077 and 36,022,811 shares issued and outstanding at September 30, 2021 and December 31, 2020, respectively	43	36
Additional paid-in capital	373,352	294,639
Accumulated deficit	(344,195)	(274,179)
Total stockholders' equity	29,200	20,496
Total liabilities and stockholders’ equity	$ 67,804	$ 59,344

Condensed Consolidated Balance Sheets (Unaudited) - Parenthetical - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Preferred Stock
Preferred stock par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock authorized (in shares)	10,000,000	10,000,000
Preferred stock issued (in shares)	0	0
Preferred stock outstanding (in shares)	0	0
Common Stock
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Common stock authorized (in shares)	150,000,000	150,000,000
Common stock issued (in shares)	42,580,077	36,022,811
Common stock outstanding (in shares)	42,580,077	36,022,811

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue:
Revenue From Contract With Customer Product And Service Extensible List	kldo:CollaborationRevenueMember	kldo:CollaborationRevenueMember	kldo:CollaborationRevenueMember	kldo:CollaborationRevenueMember
Collaboration revenue	$ 104	$ 482	$ 612	$ 732
Operating expenses:
Research and development	17,411	15,659	52,229	41,629
General and administrative	5,106	7,201	16,351	18,677
Total operating expenses	22,517	22,860	68,580	60,306
Loss from operations	(22,413)	(22,378)	(67,968)	(59,574)
Other (expense) income:
Interest income	17	21	62	244
Interest expense	(709)	(713)	(2,123)	(2,084)
Other income	20		13
Other (expense)		(61)		(190)
Total other (expense) income, net	(672)	(753)	(2,048)	(2,030)
Net loss	$ (23,085)	$ (23,131)	$ (70,016)	$ (61,604)
Net loss per share —basic and diluted	$ (0.54)	$ (0.65)	$ (1.68)	$ (1.89)
Weighted-average common shares outstanding —basic and diluted	42,577,570	35,554,128	41,613,473	32,605,592

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit
Beginning balance at Dec. 31, 2019	$ 48,883	$ 30	$ 241,412	$ (192,559)
Beginning balance (in shares) at Dec. 31, 2019		30,127,846
Exercise of stock options	1,561		1,561
Exercise of stock options (in shares)		334,444
Stock-based compensation	2,725		2,725
Common stock issued upon vesting of restricted stock units	3		3
Common stock issued upon vesting of restricted stock units (in shares)		1,250
Net loss	(19,551)			(19,551)
Ending balance at Mar. 31, 2020	33,621	$ 30	245,701	(212,110)
Ending balance (in shares) at Mar. 31, 2020		30,463,540
Beginning balance at Dec. 31, 2019	48,883	$ 30	241,412	(192,559)
Beginning balance (in shares) at Dec. 31, 2019		30,127,846
Common stock issued upon vesting of restricted stock units	3
Net loss	(61,604)
Ending balance at Sep. 30, 2020	35,901	$ 35	290,029	(254,163)
Ending balance (in shares) at Sep. 30, 2020		35,829,506
Beginning balance at Mar. 31, 2020	33,621	$ 30	245,701	(212,110)
Beginning balance (in shares) at Mar. 31, 2020		30,463,540
Issuance of common stock, net of issuance costs	33,187	$ 5	33,182
Issuance of common stock, net of issuance costs (in shares)		4,750,000
Exercise of stock options	620		620
Exercise of stock options (in shares)		143,089
Stock-based compensation	2,816		2,816
Net loss	(18,922)			(18,922)
Ending balance at Jun. 30, 2020	51,322	$ 35	282,319	(231,032)
Ending balance (in shares) at Jun. 30, 2020		35,356,629
Issuance of common stock, net of issuance costs	3,038		3,038
Issuance of common stock, net of issuance costs (in shares)		399,800
Exercise of stock options	311		311
Exercise of stock options (in shares)		73,077
Stock-based compensation	4,361		4,361
Net loss	(23,131)			(23,131)
Ending balance at Sep. 30, 2020	35,901	$ 35	290,029	(254,163)
Ending balance (in shares) at Sep. 30, 2020		35,829,506
Beginning balance at Dec. 31, 2020	20,496	$ 36	294,639	(274,179)
Beginning balance (in shares) at Dec. 31, 2020		36,022,811
Issuance of common stock, net of issuance costs	69,925	$ 6	69,919
Issuance of common stock, net of issuance costs (in shares)		6,347,156
Exercise of stock options	352		352
Exercise of stock options (in shares)		63,331
Stock-based compensation	4,229		4,229
Common stock issued upon vesting of restricted stock units	(186)		(186)
Common stock issued upon vesting of restricted stock units (in shares)		49,873
Net loss	(23,042)			(23,042)
Ending balance at Mar. 31, 2021	71,774	$ 42	368,953	(297,221)
Ending balance (in shares) at Mar. 31, 2021		42,483,171
Beginning balance at Dec. 31, 2020	20,496	$ 36	294,639	(274,179)
Beginning balance (in shares) at Dec. 31, 2020		36,022,811
Net loss	(70,016)
Ending balance at Sep. 30, 2021	29,200	$ 43	373,352	(344,195)
Ending balance (in shares) at Sep. 30, 2021		42,580,077
Beginning balance at Mar. 31, 2021	71,774	$ 42	368,953	(297,221)
Beginning balance (in shares) at Mar. 31, 2021		42,483,171
Exercise of stock options	109	$ 1	108
Exercise of stock options (in shares)		52,727
Stock-based compensation	2,376		2,376
Common stock issued upon vesting of restricted stock units	(104)		(104)
Common stock issued upon vesting of restricted stock units (in shares)		35,482
Net loss	(23,889)			(23,889)
Ending balance at Jun. 30, 2021	50,266	$ 43	371,333	(321,110)
Ending balance (in shares) at Jun. 30, 2021		42,571,380
Exercise of stock options	6		6
Exercise of stock options (in shares)		2,548
Stock-based compensation	2,032		2,032
Common stock issued upon vesting of restricted stock units	(19)		(19)
Common stock issued upon vesting of restricted stock units (in shares)		6,149
Net loss	(23,085)			(23,085)
Ending balance at Sep. 30, 2021	$ 29,200	$ 43	$ 373,352	$ (344,195)
Ending balance (in shares) at Sep. 30, 2021		42,580,077

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - Parenthetical - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020
Statement Of Stockholders Equity [Abstract]
Common stock, issuance costs			$ 4,512	$ 166	$ 306
Shares withheld for employee taxes	2,452	15,237	21,452

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities:
Net loss	$ (70,016)	$ (61,604)
Reconciliation of net loss to net cash used in operating activities:
Depreciation and amortization	1,754	1,260
Stock-based compensation	8,637	9,902
Amortization of debt discount	528	437
Non-cash interest expense	175	175
(Gain) loss on disposal of fixed assets	(9)	166
Changes in:
Prepaid expenses and other assets	(148)	(3,961)
Accounts payable	(1,830)	1,558
Accrued expense and other liabilities	975	1,846
Net cash used in operating activities	(59,934)	(50,221)
Investing activities:
Purchase of property and equipment	(693)	(3,362)
Net cash used in investing activities	(693)	(3,362)
Financing activities:
Proceeds from exercise of stock options	466	2,494
Payments related to capital lease	0	(68)
Issuance of common stock, net of issuance costs	69,925	34,324
Net settlement of vested restricted stock units to fund related employee statutory tax withholdings	(309)
Payments of issuance costs related to debt	(20)
Net cash provided by financing activities	70,062	36,750
Net increase (decrease) in cash, cash equivalents, and restricted cash	9,435	(16,833)
Cash, cash equivalents, and restricted cash, beginning of period	48,383	73,526
Cash, cash equivalents, and restricted cash, end of period	57,818	56,693
Supplemental cash flow information
Interest paid	1,601	1,393
Supplemental disclosure of non-cash investing and financing activities
Purchases of property and equipment in accounts payable and accrued expenses	0	260
Vesting of restricted shares		3
Settlement from Proceeds of issuance of common stock	$ 0	$ 1,900

Nature of the Business, Basis of Presentation, and Going Concern

9 Months Ended

Sep. 30, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Nature of the Business, Basis of Presentation, and Going Concern

1. Nature of the Business, Basis of Presentation, and Going Concern

Kaleido Biosciences, Inc. and its wholly owned subsidiaries (collectively the “Company”) is a clinical-stage biotechnology company that was incorporated in Delaware on January 27, 2015 and has a principal place of business in Lexington, Massachusetts. The Company uses its differentiated, small molecule approach to develop compounds for the treatment of inflammatory conditions and diseases, and potentially other conditions and diseases, by selectively targeting the resident microbiome to restore gut-immune homeostasis.

The Company is subject to risks common to companies in the biotechnology industry, including, but not limited to, successful development of technology, obtaining additional funding, protection of proprietary technology, compliance with government regulations, risks of failure of preclinical studies (including ex vivo assays), clinical studies and clinical trials, the need to obtain marketing approval for its drug candidates and if applicable, its consumer products, fluctuations in operating results, economic pressure impacting therapeutic pricing, dependence on key personnel, risks associated with changes in technologies, development by competitors of technological innovations and the ability to supply sufficient amounts of Microbiome Metabolic Therapies, (“MMT” or “MMTs”) at an acceptable quality level.

On June 4, 2020, the Company completed a public offering (the “Offering”), pursuant to which it issued and sold 4,750,000 shares of its common stock. The aggregate net proceeds received by the Company from the Offering were $33,182. On July 1, 2020, 185,000 shares were exercised under the Underwriters’ overallotment option for net proceeds of $1,260.

On August 4, 2020, the Company entered into an Equity Distribution Agreement (the “Sales Agreement”) with a sales agent for the sale of up to $50,000 of the Company’s shares of common stock, from time to time in an at-the-market public offering (the “ATM”). The sales agent is entitled to compensation at a fixed commission rate of 3.0% of the gross proceeds from the sale of the Company’s common stock pursuant to the Sales Agreement. During the year ended December 31, 2020, the Company sold 361,299 shares of its common stock under the ATM which resulted in aggregate net proceeds of $3,432 after payment of related commissions. During the quarter ended March 31, 2021, the Company sold 309,656 shares of its common stock which resulted in aggregate net proceeds of $4,860. No sales of common stock were made under the ATM during the quarters ended June 30, 2021 or September 30, 2021. As of September 30, 2021, there was $41,451 available under the ATM.

On February 8, 2021, the Company completed a public offering (the “2021 Offering”), pursuant to which the Company issued and sold 6,037,500 shares of common stock for net proceeds of $65,265, which included the full exercise of the Underwriters’ overallotment option.

The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. As of September 30, 2021, the Company had an accumulated deficit of $344,195. The Company expects to continue to generate operating losses and use cash in operations in the foreseeable future. As of September 30, 2021, the Company had cash and cash equivalents of $55,657, and management expects that the cash and cash equivalents at September 30, 2021 will be sufficient to fund its operating expenses and capital expenditure requirements into the second quarter of 2022. Based on its recurring losses from operations incurred since inception, expectation of continuing operating losses for the foreseeable future, and need to raise additional capital to finance its future operations, the Company has concluded that there is substantial doubt regarding the Company’s ability to continue as a going concern within one year after the date that these consolidated financial statements are issued. These financial statements do not include any adjustments that might result from the outcome of this uncertainty.

The Company will require substantial additional capital to fund its research and development and ongoing operating expenses. These capital requirements are expected to be funded through debt and equity offerings as well as possible strategic collaborations with other companies. If the Company is unable to raise additional funds when needed, it may be required to delay, reduce or eliminate its product development or future commercialization efforts, or grant rights to develop and market product candidates that the Company would otherwise prefer to develop and market itself. While there can be no assurance the Company will be able to successfully reduce operating expenses or raise additional capital, management believes that its historical success in managing cash flows and obtaining capital will continue in the foreseeable future.

A novel strain of coronavirus (COVID-19) was first identified in late 2019, and subsequently declared a global pandemic by the World Health Organization on March 11, 2020. As a result of the outbreak, many companies have experienced disruptions in their operations and in markets served. The Company has instituted some and may take additional temporary precautionary measures intended to help minimize the risk of the virus to its employees, including implementing a hybrid work environment, implementing safety measures for those employees currently going into the office to complete their work and limiting business-related travel.

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

Unaudited interim financial information

The condensed consolidated financial statements of the Company included herein have been prepared, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these condensed consolidated financial statements should be read in conjunction with the financial statements and notes thereto included in the Company's annual report on Form 10-K for the year ended December 31, 2020 filed with the SEC on March 3, 2021.

All intercompany transactions and balances of the subsidiaries have been eliminated in consolidation. In the opinion of management, the information furnished reflects all adjustments, all of which are of a normal and recurring nature, necessary for a fair representation of the results for the reported interim periods.

Use of Estimates

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

Collaboration Revenue

The Company analyzes its collaboration arrangement to assess whether it is within the scope of ASC Topic 808, Collaborative Arrangements (ASC 808), to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards that are dependent on the commercial success of such activities. To the extent the arrangement is within the scope of ASC 808, the Company will assess whether aspects of the arrangement between it and their collaboration partner are within the scope of other accounting literature. If the Company concludes that some or all aspects of the arrangement represent a transaction with a customer, it will account for those aspects of the arrangement within the scope of ASC 606, Revenue from Contracts with Customers, by applying the five-step model described below. If the Company concludes that some or all aspects of the arrangement are within the scope of ASC 808 and do not represent a transaction with a customer, the Company will recognize its allocation of the shared costs incurred with respect to the jointly conducted activities as a component of the related expense in the period incurred.

The Company recognizes revenue after applying the following five steps:

(1)

Identification of the contract, or contracts, with a customer,

(2)

Identification of the performance obligations in the contract, including whether they are distinct within the context of the contract,

(3)

Determination of the transaction price, including the constraint on variable consideration,

(4)

Allocation of the transaction price to the performance obligations in the contract, and

(5)

Recognition of revenue when, or as, performance obligations are satisfied.

If a contract is determined to be within the scope of ASC 606 at inception, the Company assesses the goods or services promised within such contract, determines which of those goods and services are performance obligations, and assesses whether each promised good or service is distinct. Promised goods and services are considered distinct provided that: (i) the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (that is, the good or service is capable of being distinct) and (ii) the entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (that is, the promise to transfer the good or service is distinct within the context of the contract). In assessing whether a promised good or service is distinct, the Company considers factors such as the research, manufacturing and commercialization capabilities of the collaboration partner and the availability of the associated expertise in the general marketplace. The Company also considers the intended benefit of the contract in assessing whether a promised good or service is separately identifiable from other promises in the contract. If a promised good or service is not distinct, an entity is required to combine that good or service with other promised goods or services until it identifies a bundle of goods or services that is distinct.

The Company may provide options to additional goods or services in such arrangements exercisable at a customer’s discretion. The Company assesses if these options provide a material right to the customer and if so, they are considered performance obligations. The identification of material rights requires judgments related to the determination of the value of the underlying good and services to the option exercise price.

The Company determines transaction price based on the amount of consideration the Company expects to receive for transferring the promised goods or services in the contract. Consideration may be fixed, variable, or a combination of both. The Company then allocates the transaction price to each performance obligation based on the relative standalone selling prices (“SSP”). SSP is determined at contract inception and is not updated to reflect changes between contract inception and when the performance obligations are satisfied. In developing the SSP for a performance obligation, the Company considers applicable market conditions and relevant entity-specific factors, including factors that were contemplated in negotiating the agreement with the customer and estimated costs.

If the consideration promised in a contract includes a variable amount, the Company estimates the amount of consideration to which it will be entitled by using the expected value method or the most likely amount method. The Company includes the unconstrained amount of estimated variable consideration in the transaction price. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. At the end of each subsequent reporting period, the Company re-evaluates the estimated variable consideration included in the transaction price and any related constraint, and if necessary, adjusts its estimate of the overall transaction price.

The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied, either at a point in time or over time, and if over time recognition is based on the use of an output or input method.

Amounts received prior to satisfying the revenue recognition criteria are recorded as deferred revenue in the Company’s condensed consolidated balance sheets. If the related performance obligation is expected to be satisfied within the next twelve months this will be classified in current liabilities. Amounts recognized as revenue prior to receipt are recorded as other current assets in the Company's balance sheets. If the Company expects to have an unconditional right to receive the consideration in the next twelve months, this will be classified in other current assets.

Recently Issued Accounting Pronouncements

In February 2016, the Financial Accounting Standards Board ("FASB") issued ASU No. 2016-02, Leases (“ASU 2016-02”), which applies to all leases and will require the Company to record most leases on the balance sheet. The Company will use a modified retrospective approach of adoption for ASU 2016-02. As an emerging growth company, this standard is required to be adopted on January 1, 2022, and the Company is evaluating the impact that the adoption of ASU 2016-02 will have on its consolidated financial statements. The Company expects to recognize a material lease obligation and right to use asset upon adoption.

Fair Value Measurements

9 Months Ended

Sep. 30, 2021

Fair Value Disclosures [Abstract]

Fair Value Measurements

3. Fair Value Measurements

The following tables set forth by level, within the fair value hierarchy, the assets carried at fair value on a recurring basis:


	Fair Value Measurements as of September 30, 2021
	Level 1		Level 2		Level 3		Total
Assets:
Money market funds included within cash and cash equivalents	$	25,415		—		—	$	25,415
Total	$	25,415		—		—	$	25,415


	Fair Value Measurements as of December 31, 2020
	Level 1		Level 2		Level 3		Total
Assets:
Money market funds included within cash and cash equivalents	$	45,410		—		—	$	45,410
Total	$	45,410		—		—	$	45,410

The fair value of money market funds was measured by the Company based on quoted market prices.

Financial Instruments Not Recorded at Fair Value – The carrying value of cash, cash equivalents, restricted cash, accounts payable and accrued expenses that are reported on the condensed consolidated balance sheets approximate their fair value due to the short-term nature of these assets and liabilities. The carrying value of the long-term debt approximates fair value as evidenced by the recent refinancings.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Property and Equipment, net

9 Months Ended

Sep. 30, 2021

Property Plant And Equipment [Abstract]

Property and Equipment, net

4. Property and Equipment, net

Property and equipment consist of the following:


	As of
	September 30, 2021			December 31, 2020
Laboratory equipment	$	7,838		$	6,843
Office and computer equipment		1,590			1,590
Leasehold improvements		1,910			1,910
Construction in process		1,144			1,612
Property and equipment – at cost		12,482			11,955
Less accumulated depreciation and amortization		(5,143	)		(3,493	)
Property and equipment – net	$	7,339		$	8,462

Depreciation and amortization expense for the three months ended September 30, 2021 and 2020 was $594 and $503, respectively. Depreciation and amortization expense for the nine months ended September 30, 2021 and 2020 was $1,754 and $1,260, respectively. During the nine months ended September 30, 2021, the Company recorded a gross fixed asset disposal of $132 and related accumulated depreciation of $103. The Company received $38 in exchange for the sale of equipment, resulting in a net gain of $9. During the nine months ended September 30, 2020, the Company recorded gross fixed asset disposal of $1,036 and related accumulated depreciation of $870.

Accrued Expenses and Other Current Liabilities

9 Months Ended

Sep. 30, 2021

Payables And Accruals [Abstract]

Accrued Expenses and Other Current Liabilities

5. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following:


	As of
	September 30, 2021		December 31, 2020
Payroll and benefits	$	2,533	$	2,943
Consulting service		419		1,049
Legal service		99		173
Research and development		5,455		3,010
Interest		175		181
Deferred revenue		150		498
Other		487		782
Accrued expenses and other current liabilities	$	9,318	$	8,636

Debt Financing

9 Months Ended

Sep. 30, 2021

Debt Disclosure [Abstract]

Debt Financing

6. Debt Financing

On December 31, 2019, the Company entered into a Credit Agreement (the “Credit Agreement”) with Hercules Capital, Inc. (the “Lender”). Under the Credit Agreement, the Company borrowed $22,500, and the Company has the option to draw down an additional $12,500 if certain milestones and conditions are met. The Company incurred fees of $410, which was paid to the Lender on the closing date. These amounts were recorded as a debt discount and are being amortized as interest expense using the effective interest method over the life of the Credit Agreement. The Credit Agreement also includes an end of term charge equal to 7.55% of the aggregate principal amount of all advances. The end of term charge, totaling $1,698 at September 30, 2021, was recognized as a debt discount and is reflected as a reduction in the carrying value of the debt and recorded in other long-term liabilities. The debt discount created by the end of term charge is being accreted and will be recognized as additional interest expense over the term of the Credit Agreement using the effective interest method.

The Credit Agreement contains customary representations and warranties, events of default and affirmative and negative covenants, including, among others, covenants that limit or restrict the Company’s ability to, among other things, incur additional indebtedness, merge or consolidate, make acquisitions, pay dividends or other distributions or repurchase equity, make investments, dispose of assets and enter into certain transactions with affiliates, in each case subject to certain exceptions. As security for its obligations under the Credit Agreement, the Company granted the Lender a first priority security interest on substantially all of the Company’s assets (other than intellectual property), and subject to certain exceptions.

The outstanding principal under the Credit Agreement has a 48-month term with interest only payments for the first 15 months, which period can be extended to up to 24 months, depending on the achievement of certain performance milestones. The principal bears interest at a rate equal to the greater of (i) 8.95% plus the prime rate minus 4.75% and (ii) 8.95%. The Credit Agreement includes mandatory prepayment provisions that require prepayment upon the occurrence of a change in control event.

On June 15, 2020, the Company entered into a Second Amendment to Loan and Security Agreement (the “Second Amendment”). The Second Amendment was entered into for the primary purpose of amending the Credit Agreement as follows: (i) the second tranche of the term loan (the “Term Loan”) was terminated; (ii) amounts available under Tranche 3 of the Term Loan was increased to $12,500 from the previous $7,500 availability amount and its availability period is extended through December 15, 2021, subject to future approval by the Lender’s investment committee; (iii) the interest-only period was extended through July 31, 2021; (iv) the interest rate on borrowings is increased by 0.4%, such that the per annum interest rate on outstanding borrowings will be the greater of (a) 9.35% and (b) 9.35% plus the Wall Street Journal prime rate minus 3.25%; and (v) the variable amount and duration of a minimum cash covenant in the Credit Agreement were amended. The Second Amendment has been accounted for as a modification and the Company incurred fees of $79, which was paid to the Lender on the closing date and were recorded as a debt discount, which will be amortized as interest expense using the effective interest method.

On April 30, 2021, the Company entered into a Third Amendment to Loan and Security Agreement (the “Third Amendment”). The Third Amendment was entered into for the primary purpose of amending the Credit Agreement as follows: (i) the interest-only period was extended through January 31, 2022; (ii) the second tranche of the term loan (the “Term Loan”) was reinstated and the related $5,000 was available to be drawn at the Company’s option on or before June 1, 2021; and (iii) the Minimum Cash Covenant was reduced from $22,500 to $15,000. The Company incurred fees of $20, which was paid to the Lender on the closing date and were recorded as a debt discount, which will be amortized as interest expense using the effective interest method. The Company did not exercise its option to draw down the second tranche of the term loan.

Future principal payments under the Credit Agreement as of September 30, 2021 are as follows (in thousands):


2021		—
2022		9,776
2023		11,671
2024		1,053
Total future principal payments		22,500
Less unamortized debt discount		984
Total balance	$	21,516

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-URI http://asc.fasb.org/topic&trid=2208564

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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+ Details

Commitments and contingencies

9 Months Ended

Sep. 30, 2021

Commitments And Contingencies Disclosure [Abstract]

Commitments and contingencies

7. Commitments and contingencies

Facilities Leases

In March 2018, the Company entered into a non-cancelable ten-year lease agreement for laboratory and office space in Lexington, Massachusetts. In March 2019, the Company exercised its option to lease additional space in the building. The lease expires in 2029, subject to one option to extend the lease for 10 years.

Rent expense for the three months ended September 30, 2021 and 2020 totaled $1,627 and $1,623, respectively. Rent expense for the nine months ended September 30, 2021 and 2020 totaled $4,879 and $5,273. Future minimum lease payments under the non-cancelable operating leases consisted of the following as of September 30, 2021:


Year Ending December 31,
2021	$	1,539
2022		6,207
2023		6,393
2024		6,584
2025		6,782
Thereafter		25,502
	$	53,007

Stockholders' Equity

9 Months Ended

Sep. 30, 2021

Stockholders Equity Note [Abstract]

Stockholders' Equity

8. Stockholders’ Equity

Modification of equity awards

On January 20, 2021, the Company entered into a separation agreement with the former Chief Medical Officer and Head of Research and Development of the Company, which amended an existing employment agreement and provided for changes in the term of service and compensation under the agreement. The outstanding options and restricted stock units held by the former Chief Medical Officer were modified to accelerate certain vesting provisions and the period of exercisability. As a result, the Company recorded stock-based compensation expense of $1,968 related to the incremental fair value of the modified awards during the first quarter of 2021.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Net Loss per Share

9 Months Ended

Sep. 30, 2021

Earnings Per Share [Abstract]

Net Loss per Share

9. Net Loss per Share

Basic and diluted net loss per common share is determined by dividing net loss by the weighted-average common shares outstanding during the period. The Company has computed diluted net loss per common share after giving consideration to all potentially dilutive common shares, including options to purchase common stock and unvested restricted common stock, outstanding during the period determined using the treasury stock method, except where the effect of including such securities would be anti-dilutive. Because the Company has reported net losses since inception, these potential common shares have been anti-dilutive and therefore basic and diluted net loss per share have been equivalent.

The following table presents securities that have been excluded from the computations of diluted weighted-average shares outstanding as they would be anti-dilutive:


	As of September 30,
	2021		2020
Options to purchase common stock		7,183,585		6,518,338
Restricted stock units		268,510		235,767
		7,452,095		6,754,105

Revenue

9 Months Ended

Sep. 30, 2021

Revenue From Contract With Customer [Abstract]

Revenue

10. Revenue

In December 2019, the Company entered into a research collaboration agreement with Janssen’s World Without Disease Accelerator (“Janssen”), part of the Janssen Pharmaceutical Companies of Johnson & Johnson, to explore the potential for MMTs to prevent the onset of childhood allergy and other atopic, immune and metabolic conditions.

The collaboration includes three milestones of research and development with deliverables due to Janssen at end of the milestone at which point Janssen will have 60 days to decide to proceed with the next milestone.

The Company assessed the Janssen collaboration agreement in accordance with ASC 808 and ASC 606 and concluded that it represents a contract with a customer and is within the scope of ASC 606. The promised goods and services represent one combined performance obligation and the entire transaction price will be allocated to that single combined performance obligation. In addition, the Company concluded the right to proceed with the following milestones does not provide any discounts to Janssen if it decides to proceed with the next milestones. As such, the Company concluded the milestone is not considered to be a material right. Each milestone is considered a separate contract and will reflect applicable standalone selling prices.

Under the Janssen collaboration agreement, Janssen is obligated to reimburse the Company for the costs incurred under an agreed upon research plan. Costs incurred are billed by the Company to Janssen at completion of each milestone. The Company recognizes revenue over the research period and as the performance obligation is satisfied using total estimated hours to be incurred throughout each milestone. For the three months ended September 30, 2021, the Company recognized $104 as collaboration revenue under the collaboration agreement with Janssen, of which $39 was previously recorded deferred revenue within current liabilities on the Company’s condensed consolidated balance sheets related to the Janssen collaboration agreement. For the nine months ended September 30, 2021, the Company recognized $612 as collaboration revenue under the collaboration agreement with Janssen, of which $348 was previously recorded deferred revenue within current liabilities on the Company’s condensed consolidated balance sheets related to the Janssen collaboration agreement. The September 30, 2021 deferred revenue balance of $150 is comprised of $40 for amounts received prior to satisfying the revenue recognition criteria and $110 for work performed to be recognized upon completion of a milestone. The expected research term of this arrangement is expected to be completed during 2021, and the aggregate consideration to be received by the Company is not expected to be material.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-URI http://asc.fasb.org/topic&trid=49130388

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+ Details

Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2021

Accounting Policies [Abstract]

Consolidation

All intercompany transactions and balances of the subsidiaries have been eliminated in consolidation.

Use of Estimates

Collaboration Revenue

The Company recognizes revenue after applying the following five steps:

(1)

Identification of the contract, or contracts, with a customer,

(2)

Identification of the performance obligations in the contract, including whether they are distinct within the context of the contract,

(3)

Determination of the transaction price, including the constraint on variable consideration,

(4)

Allocation of the transaction price to the performance obligations in the contract, and

(5)

Recognition of revenue when, or as, performance obligations are satisfied.

Recently Issued Accounting Pronouncements

Net Loss per Share

The following table presents securities that have been excluded from the computations of diluted weighted-average shares outstanding as they would be anti-dilutive:


	As of September 30,
	2021		2020
Options to purchase common stock		7,183,585		6,518,338
Restricted stock units		268,510		235,767
		7,452,095		6,754,105

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2021

Fair Value Disclosures [Abstract]

Schedule of Assets Carried at Fair Value on a Recurring Basis

The following tables set forth by level, within the fair value hierarchy, the assets carried at fair value on a recurring basis:


	Fair Value Measurements as of September 30, 2021
	Level 1		Level 2		Level 3		Total
Assets:
Money market funds included within cash and cash equivalents	$	25,415		—		—	$	25,415
Total	$	25,415		—		—	$	25,415


	Fair Value Measurements as of December 31, 2020
	Level 1		Level 2		Level 3		Total
Assets:
Money market funds included within cash and cash equivalents	$	45,410		—		—	$	45,410
Total	$	45,410		—		—	$	45,410

Property and Equipment, net (Tables)

9 Months Ended

Sep. 30, 2021

Property Plant And Equipment [Abstract]

Schedule of Property and Equipment

Property and equipment consist of the following:


	As of
	September 30, 2021			December 31, 2020
Laboratory equipment	$	7,838		$	6,843
Office and computer equipment		1,590			1,590
Leasehold improvements		1,910			1,910
Construction in process		1,144			1,612
Property and equipment – at cost		12,482			11,955
Less accumulated depreciation and amortization		(5,143	)		(3,493	)
Property and equipment – net	$	7,339		$	8,462

Accrued Expenses and Other Current Liabilities (Tables)

9 Months Ended

Sep. 30, 2021

Payables And Accruals [Abstract]

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following:


	As of
	September 30, 2021		December 31, 2020
Payroll and benefits	$	2,533	$	2,943
Consulting service		419		1,049
Legal service		99		173
Research and development		5,455		3,010
Interest		175		181
Deferred revenue		150		498
Other		487		782
Accrued expenses and other current liabilities	$	9,318	$	8,636

Debt Financing (Tables)

9 Months Ended

Sep. 30, 2021

Debt Disclosure [Abstract]

Summary of Future Principal Payments

Future principal payments under the Credit Agreement as of September 30, 2021 are as follows (in thousands):


2021		—
2022		9,776
2023		11,671
2024		1,053
Total future principal payments		22,500
Less unamortized debt discount		984
Total balance	$	21,516

Commitments and contingencies (Tables)

9 Months Ended

Sep. 30, 2021

Commitments And Contingencies Disclosure [Abstract]

Future Minimum Lease Payments

Future minimum lease payments under the non-cancelable operating leases consisted of the following as of September 30, 2021:


Year Ending December 31,
2021	$	1,539
2022		6,207
2023		6,393
2024		6,584
2025		6,782
Thereafter		25,502
	$	53,007

Net Loss per Share (Tables)

9 Months Ended

Sep. 30, 2021

Earnings Per Share [Abstract]

Schedule of Securities Excluded from Computation of Diluted Weighted-Average Shares Outstanding

The following table presents securities that have been excluded from the computations of diluted weighted-average shares outstanding as they would be anti-dilutive:


	As of September 30,
	2021		2020
Options to purchase common stock		7,183,585		6,518,338
Restricted stock units		268,510		235,767
		7,452,095		6,754,105

Nature of the Business, Basis of Presentation, and Going Concern (Details) - USD ($)				3 Months Ended			9 Months Ended		12 Months Ended
	Feb. 08, 2021	Jul. 01, 2020	Jun. 04, 2020	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Aug. 04, 2020
Conversion of Stock [Line Items]
Net proceeds from exercise of shares							$ 466,000	$ 2,494,000
Common stock, value, issued under the ATM sales agreement				$ 43,000			43,000		$ 36,000
Accumulated deficit				(344,195,000)			(344,195,000)		(274,179,000)
Cash and cash equivalents				$ 55,657,000			$ 55,657,000		46,222,000
Public Offering
Conversion of Stock [Line Items]
Issuance of common stock (in shares)	6,037,500		4,750,000
Net proceeds from offering	$ 65,265,000		$ 33,182,000
Over-Allotment Option
Conversion of Stock [Line Items]
Number of shares exercised		185,000
Net proceeds from exercise of shares		$ 1,260,000
At-The-Market Sales Agreement
Conversion of Stock [Line Items]
Issuance of common stock (in shares)				0	0
Common stock, value, issued under the ATM sales agreement						$ 309,656			361,299
Percentage of gross proceeds payable as commission							3.00%
Net proceeds from the sale of common stock						$ 4,860,000			$ 3,432,000
Common stock, value, available under the ATM sales agreement				$ 41,451,000			$ 41,451,000
At-The-Market Sales Agreement \| Maximum
Conversion of Stock [Line Items]
Common stock, value, issued under the ATM sales agreement										$ 50,000,000

Fair Value Measurements - Schedule of Assets Carried at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets, Fair Value Disclosure [Abstract]
Assets, fair value disclosure	$ 25,415	$ 45,410
Money market funds included within cash and cash equivalents
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents fair value disclosure	25,415	45,410
Level 1
Assets, Fair Value Disclosure [Abstract]
Assets, fair value disclosure	25,415	45,410
Level 1 \| Money market funds included within cash and cash equivalents
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents fair value disclosure	$ 25,415	$ 45,410

Property and Equipment, net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment – at cost	$ 12,482		$ 12,482		$ 11,955
Less accumulated depreciation and amortization	(5,143)		(5,143)		(3,493)
Property and equipment – net	7,339		7,339		8,462
Depreciation and amortization	594	$ 503	1,754	$ 1,260
Gross fixed asset disposal			132	1,036
Accumulated depreciation related to fixed asset disposal			103	$ 870
Proceeds from sale of equipment			38
Net gain on sale of equipment			9
Laboratory equipment
Property Plant And Equipment [Line Items]
Property and equipment – at cost	7,838		7,838		6,843
Office and computer equipment
Property Plant And Equipment [Line Items]
Property and equipment – at cost	1,590		1,590		1,590
Leasehold improvements
Property Plant And Equipment [Line Items]
Property and equipment – at cost	1,910		1,910		1,910
Construction in process
Property Plant And Equipment [Line Items]
Property and equipment – at cost	$ 1,144		$ 1,144		$ 1,612

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Payroll and benefits	$ 2,533	$ 2,943
Consulting service	419	1,049
Legal service	99	173
Research and development	5,455	3,010
Interest	175	181
Deferred revenue	150	498
Other	487	782
Accrued expenses and other current liabilities	$ 9,318	$ 8,636

Debt Financing - Narrative (Details) - USD ($)			1 Months Ended		9 Months Ended
Debt Financing - Narrative (Details) - USD ($)	Sep. 30, 2021	Jun. 15, 2020	Apr. 30, 2021	Dec. 31, 2019	Sep. 30, 2021	Apr. 29, 2021
2019 Credit Agreement
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity				$ 22,500,000
Option to draw down an additional amount				12,500,000
Line of credit facility fees amount payable				$ 410,000
Credit agreement end of term charge percentage				7.55%
debt discount	$ 1,698,000
Credit agreement, expiration period				48 months
Credit agreement interest payment period				15 months
Credit agreement interest payment extension period				24 months
2019 Credit Agreement \| Line of Credit
Line of Credit Facility [Line Items]
Debt instrument effective percentage interest rate				8.95%
Debt instrument, basis spread on variable rate				4.75%
Debt instrument, description of variable rate basis					The principal bears interest at a rate equal to the greater of (i) 8.95% plus the prime rate minus 4.75% and (ii) 8.95%.
Tranche 3 \| Term Loan
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity		$ 12,500,000
Current borrowing capacity		$ 7,500,000
Debt instrument, maturity date		Dec. 15, 2021
Debt instrument, interest maturity date		Jul. 31, 2021
2020 Amendment \| Term Loan
Line of Credit Facility [Line Items]
Line of credit facility fees amount payable		$ 79,000
Debt instrument, basis spread on variable rate		9.35%
Debt instrument, description of variable rate basis					9.35% plus the Wall Street Journal prime rate minus 3.25%
2020 Amendment \| Term Loan \| Maximum
Line of Credit Facility [Line Items]
Debt instrument effective percentage interest rate		0.40%
2021 Amendment \| Term Loan
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity			$ 15,000,000			$ 22,500,000
Li