Synlogic (SYBX) 10-Q 13 May 21 2021 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2021	May 06, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Trading Symbol	SYBX
Entity Registrant Name	SYNLOGIC, INC.
Security Exchange Name	NASDAQ
Entity Central Index Key	0001527599
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	false
Title of 12(b) Security	Common Stock, par value $0.001 per share
Entity Common Stock, Shares Outstanding		52,368,221
Entity Address, State or Province	MA
Entity File Number	001-37566
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-1824804
Entity Address, Address Line One	301 Binney St.
Entity Address, Address Line Two	Suite 402
Entity Address, City or Town	Cambridge
Entity Address, Postal Zip Code	02142
City Area Code	617
Local Phone Number	401-9975
Entity Interactive Data Current	Yes
Document Quarterly Report	true
Document Transition Report	false

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 26,704	$ 32,507
Short-term marketable securities	67,648	67,937
Prepaid expenses and other current assets	6,845	6,402
Total current assets	101,197	106,846
Property and equipment, net	10,174	10,776
Right of use asset - operating lease	15,065	15,527
Restricted cash	1,097	1,097
Prepaid research and development, net of current portion	8,208	9,590
Other assets	4	4
Total assets	135,745	143,840
Current liabilities:
Accounts payable	1,563	1,995
Accrued expenses	2,802	3,773
Lease liability - operating lease	2,620	2,531
Finance lease obligations	1	2
Total current liabilities	6,986	8,301
Long-term liabilities:
Lease liability - operating lease, net of current portion	19,578	20,273
Other long-term liabilities	131	131
Total long-term liabilities	19,709	20,404
Commitments and contingencies (Note 11)
Stockholders' equity
Common stock, $0.001 par value 250,000,000 shares authorized as of March 31, 2021 and December 31, 2020. 40,873,526 shares issued and outstanding as of March 31, 2021 and 38,183,273 shares issued and outstanding as of December 31, 2020.	41	38
Additional paid-in capital	354,286	345,394
Accumulated other comprehensive income	5	14
Accumulated deficit	(245,282)	(230,311)
Total stockholders' equity	109,050	115,135
Total liabilities and stockholders' equity	$ 135,745	$ 143,840

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.001	$ 0.001
Common stock, authorized	250,000,000	250,000,000
Common stock, Issued	40,873,526	38,183,273
Common stock, outstanding	40,873,526	38,183,273

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Revenue		$ 100
Operating expenses:
Research and development	$ 11,180	12,677
General and administrative	3,851	3,821
Total operating expenses	15,031	16,498
Loss from operations	(15,031)	(16,398)
Other income (expense):
Interest and investment income	60	574
Interest expense		(3)
Other expense		(1)
Other income (expense), net	60	570
Net loss	$ (14,971)	$ (15,828)
Net loss per share - basic and diluted	$ (0.36)	$ (0.46)
Weighted-average common stock outstanding - basic and diluted	41,545,050	34,233,688
Comprehensive loss:
Net loss	$ (14,971)	$ (15,828)
Net unrealized (loss) gain on marketable securities	(9)	(55)
Comprehensive loss	$ (14,980)	$ (15,883)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	At-the-market Offering	Common Stock $0.001 Par Value	Common Stock $0.001 Par ValueAt-the-market Offering	Additional Paid-in Capital	Additional Paid-in CapitalAt-the-market Offering	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2019	$ 156,905		$ 33		$ 327,900		$ 110	$ (171,138)
Balance (in Shares) at Dec. 31, 2019			32,266,814
Issuance of restricted stock, shares			226,335
Cancellation of restricted stock			(33,755)
Equity-based compensation expense	1,095				1,095
Unrealized gain (loss) on securities	(55)						(55)
Net loss	(15,828)							(15,828)
Balance at Mar. 31, 2020	142,117		$ 33		328,995		55	(186,966)
Balance (in Shares) at Mar. 31, 2020			32,459,394
Balance at Dec. 31, 2020	$ 115,135		$ 38		345,394		14	(230,311)
Balance (in Shares) at Dec. 31, 2020			38,183,273
Proceeds from issuance of common stock, net of issuance costs		$ 8,050		$ 3		$ 8,047
Proceeds from issuance of common stock, net of issuance costs, Shares				2,447,211
Exercise of options, shares	216		216
Issuance of restricted stock, shares			242,454
Issuance of common stock under employee stock purchase plan	$ 33				33
Issuance of common stock under employee stock purchase plan, Shares			19,061
Restricted stock awards withheld for payment of employees' withholding tax liability	(65)				(65)
Restricted stock awards withheld for payment of employees' withholding tax liability, Shares			(15,970)
Cancellation of restricted stock			(2,719)
Equity-based compensation expense	877				877
Unrealized gain (loss) on securities	(9)						(9)
Net loss	(14,971)							(14,971)
Balance at Mar. 31, 2021	$ 109,050		$ 41		$ 354,286		$ 5	$ (245,282)
Balance (in Shares) at Mar. 31, 2021			40,873,526

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net loss	$ (14,971)	$ (15,828)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	626	667
Equity-based compensation expense	877	1,095
Accretion/amortization of investment securities	105	(45)
Reduction in carrying amount of operating lease right of use asset	462	420
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(443)	509
Prepaid research and development, net of current portion	1,382	3,327
Accounts payable and accrued expenses	(1,408)	(2,129)
Deferred revenue		(100)
Operating lease liabilities	(606)	(395)
Net cash used in operating activities	(13,976)	(12,479)
Cash flows from investing activities:
Purchases of marketable securities	(27,091)	(14,269)
Proceeds from maturity of marketable securities	25,996	18,852
Proceeds from redemption of marketable securities	1,270	1,500
Purchases of property and equipment	(21)	(266)
Net cash provided by investing activities	154	5,817
Cash flows from financing activities:
Payments on finance lease obligations	(1)	(69)
Proceeds from employee stock purchases and exercise of stock options	33
Payment of employee withholding taxes relating to restricted stock awards	(65)
Net cash provided by (used in) financing activities	8,019	(69)
Net decrease in cash, cash equivalents and restricted cash	(5,803)	(6,731)
Cash, cash equivalents and restricted cash at beginning of period	33,604	27,281
Cash, cash equivalents and restricted cash at end of period	27,801	20,550
Supplemental disclosure of non-cash investing activities:
Property and equipment purchases included in accounts payable and accrued expenses	3	41
Supplemental disclosure of non-cash financing activities:
Issuance costs included in accounts payable and accrued expenses	2
Cash paid for interest		$ 3
At-the-market Offering
Cash flows from financing activities:
Proceeds from issuance of common stock, net of issuance costs	$ 8,052

Nature of Business

Nature of Business	3 Months Ended
	Mar. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Business	(1) Nature of Business Organization Synlogic, Inc., together with its wholly owned and consolidated subsidiaries (“Synlogic” or the “Company”), is a clinical-stage biopharmaceutical company focused on the drug discovery and development of Synthetic Biotic™ medicines. Synthetic Biotic medicines are generated from Synlogic’s proprietary drug discovery and development platform, leveraging a reproducible, modular approach to synthetic biology to develop beneficial microbes, which perform or deliver critical therapeutic functions. Synthetic Biotic medicines are designed to metabolize a toxic substance or compensate for missing or damaged metabolic pathways. Synlogic’s goal is to discover, develop and ultimately commercialize Synthetic Biotic medicines. Since incorporation, the Company has devoted substantially all of its efforts to the research and development of its product candidates. On August 28, 2017, Synlogic, Inc., formerly known as Mirna Therapeutics, Inc. (NASDAQ: MIRN) (“Mirna”), completed a business combination with Synlogic, a private company, pursuant to the Agreement and Plan of Merger and Reorganization, dated as of May 15, 2017 (the “Merger Agreement”), pursuant to which the private Synlogic entity survived as a wholly owned subsidiary of Mirna (the “Merger”). Immediately after completion of the Merger, Mirna changed its name to “Synlogic, Inc.” (NASDAQ: SYBX). Risks and Uncertainties At March 31, 2021, the Company had approximately $94.4 million in cash, cash equivalents, and short-term marketable securities, $1.1 million of restricted cash and an accumulated deficit of approximately $245.3 million. Since its inception through March 31, 2021, the Company has primarily financed its operations through the issuance of preferred stock, units and warrants, the sale of its common stock, the AbbVie collaboration, and cash received in the Merger. In the absence of positive cash flows from operations, the Company is highly dependent on its ability to find additional sources of funding in the form of debt or equity financing. Management believes that the Company has sufficient cash to fund its operations through at least twelve months from the issuance of these financial statements. As an early-stage company, the Company is subject to a number of risks common to other life science companies, including, but not limited to, raising additional capital, development by its competitors of new technological innovations, risk of failure in preclinical and clinical studies, safety and efficacy of its product candidates in clinical trials, the risk of relying on external parties such as contract research organizations (“CROs”) and contract manufacturing organizations (“CMOs”), the regulatory approval process, market acceptance of the Company’s products once approved, lack of marketing and sales history, dependence on key personnel and protection of proprietary technology. The Company’s therapeutic programs are currently pre-commercial, spanning discovery through early development and will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval, prior to commercialization of any product candidates. These efforts require significant amounts of additional capital, adequate personnel, infrastructure, and extensive compliance-reporting capabilities. There can be no assurance that the Company’s research and development will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained, that any products developed will obtain necessary regulatory approval or that any approved products will be commercially viable. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will generate revenue from product sales. The Company may never achieve profitability, and unless and until it does, it will continue to need to raise additional capital or obtain financing from other sources, such as strategic collaborations or partnerships.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	( 2) Summary of Significant Accounting Policies The significant accounting policies described in the Company’s audited financial statements as of and for the year ended December 31, 2020, and the notes thereto, which are included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020, filed with the Securities and Exchange Commission (“SEC”) on March 25, 2021 (the “2020 Annual Report”), have had no material changes during the three months ended March 31, 2021. The updated accounting policy and the impact of adoption are discussed in the “Recently Adopted Accounting Pronouncements” section in this note. Basis of Presentation The accompanying consolidated financial statements and the related disclosures as of March 31, 2021 and for the three months ended March 31, 2021 and 2020 are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) and the rules and regulations of the SEC for interim financial statements. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. These interim consolidated financial statements should be read in conjunction with the Company’s 2020 and 2019 audited consolidated financial statements and notes included in the Company’s 2020 Annual Report. The December 31, 2020 consolidated balance sheet included herein was derived from the audited financial statements as of that date but does not include all disclosures including notes required by GAAP for complete financial statements. In the opinion of management, the unaudited interim consolidated financial statements reflect all adjustments, consisting of normal and recurring adjustments, necessary for the fair presentation of the Company’s financial position and results of operations for the three months ended March 31, 2021 and 2020 . The results of operations for the interim periods are not necessarily indicative of the results to be expected for the year ending December 31, 2021 or any other interim period or future year or period. Principles of Consolidation The accompanying consolidated financial statements include the accounts of Synlogic and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Recently Adopted Accounting Pronouncements In October 2020, the FASB issued an amendment, ASU 2020-08, Codification Improvements to Subtopic 310-20, Receivables – Nonrefundable Fees and Other Costs, Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities. The amendment shall be effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. The Company adopted the new guidance effective on January 1, 2021 which had an immaterial impact on its consolidated financial statements. Recently Issued Pronouncements In June 2016, the FASB issued ASU 2016-13 - Measurement of Credit Losses on Financial Statements Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842): Effective Dates The Company has evaluated other recently issued accounting pronouncements and has concluded that that the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s financial position or results of operations upon adoption.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	( 3 ) Fair Value of Financial Instruments The tables below present information about the Company’s assets that are measured at fair value on a recurring basis and indicate the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value, as described under Note 2 , Summary of Significant Accounting Policies, The Company’s investment portfolio includes many fixed income securities that do not always trade on a daily basis. As a result, the pricing services used by the Company applied other available information as applicable through processes such as benchmark yields, benchmarking of like securities, sector groupings and matrix pricing to prepare evaluations. In addition, model processes were used to assess interest rate impact and develop prepayment scenarios. These models take into consideration relevant credit information, perceived market movements, sector news and economic events. The inputs into these models may include benchmark yields, reported trades, broker-dealer quotes, issuer spreads and other relevant data. At March 31, 2021 and December 31, 2020, the Company has classified assets measured at fair value on a recurring basis as follows (in thousands): Fair Value Measurements at Reporting Date Using March 31, Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Description 2021 (Level 1) (Level 2) (Level 3) Money market funds $ 26,703 $ 26,703 $ — $ — Commercial paper 42,469 — 42,469 — Corporate debt securities 16,376 — 16,376 — U.S. government agency securities and treasuries 8,803 8,803 — — Total $ 94,351 $ 35,506 $ 58,845 $ — Fair Value Measurements at Reporting Date Using December 31, Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Description 2020 (Level 1) (Level 2) (Level 3) Money market funds $ 32,506 $ 32,506 $ — $ — Commercial paper 40,477 — 40,477 — Corporate debt securities 18,637 — 18,637 — U.S. government agency securities and treasuries 8,823 8,823 — — Total $ 100,443 $ 41,329 $ 59,114 $ — Cash equivalents, prepaid expenses and other current assets, accounts payable and accrued expenses at March 31, 2021 and December 31, 2020 are carried at amounts that approximate fair value due to their short-term maturities. Finance lease obligations at March 31, 2021 and December 31, 2020 approximate fair value as they bear interest at a rate approximating a market interest rate.

Available-for-Sale Investments

Available-for-Sale Investments	3 Months Ended
	Mar. 31, 2021
Investments Debt And Equity Securities [Abstract]
Available-for-Sale Investments	( 4 ) Available-for-Sale Investments The following tables summarize the available-for-sale securities held at March 31, 2021 and December 31, 2020 (in thousands): March 31, 2021 Amortized cost Gross unrealized gains Gross unrealized losses Fair Value Commercial paper $ 42,466 $ 4 $ (1 ) $ 42,469 Corporate debt securities 16,378 3 (5 ) 16,376 U.S. government agency securities 8,799 4 — 8,803 Total $ 67,643 $ 11 $ (6 ) $ 67,648 December 31, 2020 Amortized cost Gross unrealized gains Gross unrealized losses Fair Value Commercial paper $ 40,467 $ 11 $ (1 ) $ 40,477 Corporate debt securities 18,634 4 (1 ) 18,637 U.S. government agency securities 8,822 1 — 8,823 Total $ 67,923 $ 16 $ (2 ) $ 67,937 The contractual maturity of all securities held at March 31, 2021 was nine months or less. There were nine and eight investments in an unrealized loss position at March 31, 2021 and December 31, 2020, respectively, none of which had been in an unrealized loss position for more than twelve months. The aggregate fair value of the securities in an unrealized loss position at March 31, 2021 and December 31, 2020 was $28.8 million and $20.1 million, respectively. The Company reviews its investments for other-than-temporary impairment whenever the fair value of an investment is less than amortized cost and evidence indicates that an investment’s carrying amount is not recoverable within a reasonable period of time. To determine whether an impairment is other-than-temporary, the Company considers whether it has the ability and intent to hold the investment until a market price recovery and considers whether evidence indicating the cost of the investment is recoverable outweighs evidence to the contrary. The Company did not hold any securities with an other-than-temporary impairment at March 31, 2021. Gross realized gains and losses on the sales of investments have not been material to the Company’s consolidated statement of operations.

Property and Equipment, Net

Property and Equipment, Net	3 Months Ended
	Mar. 31, 2021
Property Plant And Equipment [Abstract]
Property and Equipment, Net	( 5 ) Property and Equipment, net Property and equipment, net consists of the following (in thousands): March 31, December 31, 2021 2020 Laboratory equipment $ 7,829 $ 7,793 Computer and office equipment 769 769 Furniture and fixtures 421 421 Leasehold improvements 9,514 9,514 Construction in progress 516 528 19,049 19,025 Less accumulated depreciation (8,875 ) (8,249 ) $ 10,174 $ 10,776

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2021
Payables And Accruals [Abstract]
Accrued Expenses	( 6 ) Accrued Expenses Accrued expenses consist of the following (in thousands): March 31, December 31, 2021 2020 Payroll related $ 1,436 $ 3,005 Professional fees 454 215 Research and development 577 230 Other 335 323 $ 2,802 $ 3,773

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2021
Equity [Abstract]
Stockholders' Equity	( 7 ) Stockholders’ Equity In June 2019, the Company issued to Ginkgo Bioworks, Inc. (“Ginkgo”) an aggregate of 6,340,771 shares of common stock at a purchase price per share of $9.00, and pre-funded warrants (the “Pre-Funded Warrants”) to purchase an aggregate of 2,548,117 shares of common stock at an exercise price of $9.00 per share, with $8.99 of such exercise price paid at the closing of the offering. The net proceeds to the Company were approximately $79.9 million. No On October 13, 2017 the Company entered into a sales agreement with Cowen and Company, LLC (“Cowen”) with respect to an at-the-market (“ATM”) offering program under which the Company may offer and sell, from time to time at its sole discretion, shares of its common stock, through Cowen as its sales agent. In an ATM offering, exchange-listed companies incrementally sell newly issued shares into the secondary trading market through a designated broker-dealer at prevailing market prices. During the three months ended March 31, 2021, 2,447,211 shares of common stock were sold pursuant to the ATM, respectively, resulting in net proceeds of approximately $8.1 million. The Company has reserved for future issuance the following shares of common stock related to the potential exercise of Pre-Funded Warrants, exercise of stock options, and the employee stock purchase plan: March 31, 2021 Common stock issuable under pre-funded warrants 2,548,117 Options to purchase common stock 1,663,868 Employee Stock Purchase Plan 708,433 Total 4,920,418

Equity-based Compensation and E

Equity-based Compensation and Equity Incentive Plans	3 Months Ended
	Mar. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Equity-based Compensation and Equity Incentive Plans	( 8 ) Equity‑based Compensation and Equity Incentive Plans Equity Plans Pursuant to the evergreen provision of the 2015 Equity Incentive Award Plan (the “2015 Plan”), which allows for an annual increase in the number of shares of common stock available for issuance, the Company added 1,909,163 shares to the 2015 Plan on January 1, 2021. Pursuant to the evergreen provision of the 2015 Employee Stock Purchase Plan (“ESPP”), which allows for an annual increase in the number of shares of common stock available for issuance, the Company added 381,832 shares to the ESPP on January 1, 2021. There were 19,061 options exercised to purchase shares of common stock under the ESPP during the three months ended March 31, 2021. For a full description of the Company’s equity plans, refer to Note 9, Equity-based Compensation and Equity Incentive Plans Stock Options The following table summarizes stock option activity during the three months ended March 31, 2021. Stock options outstanding Weighted average Weighted remaining Aggregate average contractual intrinsic Number of exercise term value (a) options price (in years) (in thousands) Outstanding at December 31, 2020 3,343,836 $ 6.00 8.4 $ 399 Granted 1,331,478 3.49 — Exercised (216 ) 1.70 — Cancelled/Forfeited (97,981 ) 8.25 45 Outstanding at March 31, 2021 4,577,117 5.23 8.7 2,829 Vested or expected to vest at March 31, 2021 4,577,117 5.23 8.7 2,829 Exercisable at March 31, 2021 1,527,574 8.57 7.5 $ 566 (a) The aggregate intrinsic value is calculated as the difference between the exercise price of the options and the fair market value of the underlying common stock for the options that were in the money at March 31, 2021 and December 31, 2020. 2,966,180 and 970,826 options were in the money at March 31, 2021 and December 31, 2020, respectively. As of March 31, 2021, there was $6.9 million of unrecognized share-based compensation related to unvested stock option grants which is expected to be recognized over a weighted average period of 2.8 years. The total unrecognized share-based compensation cost will be adjusted for actual forfeitures as they occur. Restricted Common Stock The following table shows restricted stock activity during the three months ended March 31, 2021: Restricted stock awards Weighted average grant date Number of fair value shares (per share) Unvested at December 31, 2020 478,207 $ 2.19 Granted 242,454 3.50 Vested (302,784 ) 2.48 Forfeited (2,719 ) 2.36 Unvested at March 31, 2021 415,158 $ 2.75 As of March 31, 2021, there was approximately $1.1 million of unrecognized share-based compensation related to restricted stock awards granted, which is expected to be recognized over a weighted average period of 3.8 years. The total unrecognized share-based compensation cost will be adjusted for actual forfeitures as they occur. Employee Stock Purchase Plan The ESPP is considered a compensatory plan with the related compensation cost expensed over the six-month offering periods. The compensation cost for the three months ended March 31, 2021 was $6,000. There was no compensation expense related to the ESPP for the three months ended March 31, 2020. Equity Compensation The Company has recorded total equity-based compensation expense of approximately $0.9 million during the three months ended March 31, 2021 and $1.1 million during the three months ended March 31, 2020. The following table summarizes equity‑based compensation expense within the Company’s consolidated statements of operations and comprehensive loss for the three months ended March 31, 2021 and 2020 (in thousands): Three Months Ended March 31, 2021 2020 Research and development $ 415 $ 441 General and administrative 462 654 $ 877 $ 1,095 The following table summarizes equity‑based compensation expense by type of award for the three months ended March 31, 2021 and 2020 (in thousands): Three Months Ended March 31, 2021 2020 Stock options $ 699 $ 875 Restricted stock awards 172 220 ESPP 6 — $ 877 $ 1,095

Collaboration Agreements

Collaboration Agreements	3 Months Ended
	Mar. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration Agreements	( 9 ) Collaboration Agreements Ginkgo Collaboration In 2017, the Company established a technology collaboration with Ginkgo. In June 2019, the Company expanded its collaboration and entered into an agreement with Ginkgo for the research and development of engineered microbial therapeutic products (See Note 7). Under the 2019 expanded agreement, the Company made a prepayment to Ginkgo of $30.0 million for its foundry services that will be provided to the Company over an initial term of five years. The prepayment of foundry services is recorded in Prepaid expenses and other current assets and Prepaid research and development, net of current portion on the March 31, 2021 consolidated balance sheet. At March 31, 2021, the Company had remaining balances of $5.1 million and $7.6 million of current and non-current pre-paid research and development costs related to this transaction, respectively. AbbVie Collaboration Agreement In May 2020, we announced the termination of our collaboration with AbbVie to develop Synthetic Biotic medicines for the treatment of types of IBD, including Crohn’s disease and ulcerative colitis. Upon termination, we regained all rights to develop these and new IBD Synthetic Biotic medicines for all effectors targeting IBD. This allows us to fully leverage our expertise in strain engineering, quantitative biology, regulatory, and manufacturing to expand our wholly owned GI-based program portfolio to include IBD. We further regained the rights to partner these IBD programs. Revenue associated with performance obligations under the AbbVie Agreement was recognized as the research and development services were provided using an input method, according to the full-time equivalents incurred. The research and development activities were expected to be performed over a period of approximately 54 months. The transfer of control occurs over time and, in management’s judgment, was the best measure of progress towards satisfying the performance obligation. The amounts received that had not yet been recognized as revenue were recorded in deferred revenue on the Company’s consolidated balance sheet. The Company recognized no revenue for the three months ended March 31, 2021 and $0.1 million for the corresponding period in 2020. There is no deferred revenue on the Company’s consolidated balance sheet as of March 31, 2021, as the remainder of the revenue was recognized when the agreement was terminated.

Net Loss per Share

Net Loss per Share	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Net Loss per Share	( 10 ) Net Loss per Share Basic net loss per share is computed using the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is computed using the sum of the weighted-average number of shares of common stock outstanding during the period and if dilutive, the weighted-average number of potential shares of common stock, including unvested restricted common stock and outstanding stock options. In June 2019, the Company sold 6,340,771 shares of common stock and Pre-Funded Warrants to purchase an aggregate of 2,548,117 shares of common stock at an exercise price of $9.00 per share, with $8.99 of such exercise price paid at the closing of the offering (see Note 10 , Ginkgo Collaboration, The Company’s potentially dilutive shares, which include outstanding stock options and unvested restricted common stock/units, are considered to be common share equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. The following potential common shares, presented based on amounts outstanding at each period end, were excluded from the calculation of the diluted net loss per share attributable to common stockholders for the period indicated because including them would have had an anti-dilutive effect. As of March 31, 2021 2020 Unvested restricted common stock awards 415,158 770,191 Outstanding options to purchase common stock 4,577,117 3,252,459 Potential shares issuable under the ESPP — —

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	( 11 ) Commitments and Contingencies In the ordinary course of business, the Company may be subject to legal proceedings, claims and litigation as the Company operates in an industry susceptible to patent legal claims. The Company accounts for estimated losses with respect to legal proceedings and claims when such losses are probable and estimable. Legal costs associated with these matters are expensed when incurred. The Company is not currently a party to any material legal proceedings. The Company’s commitments described in the Company’s consolidated financial statements as of and for the year ended December 31, 2020 and the notes thereto included in the Company’s Annual Report on Form 10-K filed with the SEC on March 25, 2021, have had no material changes during the three months ended March 31, 2021.

Related-Party Transactions

Related-Party Transactions	3 Months Ended
	Mar. 31, 2021
Related Party Transactions [Abstract]
Related-Party Transactions	(1 2 ) Related-Party Transactions In June 2019, the Company expanded its collaboration and entered into an agreement with Ginkgo for the research and development of engineered microbial therapeutic products. As of March 31, 2021, Ginkgo owns 6,340,771 shares of the Company’s outstanding common stock. See Note 10, Ginkgo Collaboration, in the audited financial statements included in the Company’s 2020 Annual Report. Under the agreement the Company made a prepayment to Ginkgo of $30.0 million for its foundry services that will be provided to the Company over an initial term of five years. At March 31, 2021, the Company had remaining balances of $5.1 million and $7.6 million of current and non-current pre-paid research and development costs related to this transaction, respectively. For the three months ended March 31, 2021, the Company used $0.9 million of the pre-paid research and development expenses.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	(13) Subsequent Events In April 2021, the Company sold 11,500,000 shares of its common stock at a public offering price of $3.00 per share pursuant to underwritten public offering. The net proceeds to the Company from the offering, after deducting the underwriting discounts and commissions and offering expenses payable by the Company, were approximately $32.6 million. All shares of common stock sold in the offering were sold by the Company.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements and the related disclosures as of March 31, 2021 and for the three months ended March 31, 2021 and 2020 are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) and the rules and regulations of the SEC for interim financial statements. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. These interim consolidated financial statements should be read in conjunction with the Company’s 2020 and 2019 audited consolidated financial statements and notes included in the Company’s 2020 Annual Report. The December 31, 2020 consolidated balance sheet included herein was derived from the audited financial statements as of that date but does not include all disclosures including notes required by GAAP for complete financial statements. In the opinion of management, the unaudited interim consolidated financial statements reflect all adjustments, consisting of normal and recurring adjustments, necessary for the fair presentation of the Company’s financial position and results of operations for the three months ended March 31, 2021 and 2020 . The results of operations for the interim periods are not necessarily indicative of the results to be expected for the year ending December 31, 2021 or any other interim period or future year or period.
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include the accounts of Synlogic and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In October 2020, the FASB issued an amendment, ASU 2020-08, Codification Improvements to Subtopic 310-20, Receivables – Nonrefundable Fees and Other Costs, Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities. The amendment shall be effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. The Company adopted the new guidance effective on January 1, 2021 which had an immaterial impact on its consolidated financial statements.
Recently Issued Pronouncements	Recently Issued Pronouncements In June 2016, the FASB issued ASU 2016-13 - Measurement of Credit Losses on Financial Statements Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842): Effective Dates The Company has evaluated other recently issued accounting pronouncements and has concluded that that the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s financial position or results of operations upon adoption.

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Schedule of Company's Classified Assets Measured at Fair Value on Recurring Basis	At March 31, 2021 and December 31, 2020, the Company has classified assets measured at fair value on a recurring basis as follows (in thousands): Fair Value Measurements at Reporting Date Using March 31, Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Description 2021 (Level 1) (Level 2) (Level 3) Money market funds $ 26,703 $ 26,703 $ — $ — Commercial paper 42,469 — 42,469 — Corporate debt securities 16,376 — 16,376 — U.S. government agency securities and treasuries 8,803 8,803 — — Total $ 94,351 $ 35,506 $ 58,845 $ — Fair Value Measurements at Reporting Date Using December 31, Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Description 2020 (Level 1) (Level 2) (Level 3) Money market funds $ 32,506 $ 32,506 $ — $ — Commercial paper 40,477 — 40,477 — Corporate debt securities 18,637 — 18,637 — U.S. government agency securities and treasuries 8,823 8,823 — — Total $ 100,443 $ 41,329 $ 59,114 $ —

Available-for-Sale Investments

Available-for-Sale Investments (Tables)	3 Months Ended
	Mar. 31, 2021
Investments Debt And Equity Securities [Abstract]
Summary of Available-for-Sale Securities Held	The following tables summarize the available-for-sale securities held at March 31, 2021 and December 31, 2020 (in thousands): March 31, 2021 Amortized cost Gross unrealized gains Gross unrealized losses Fair Value Commercial paper $ 42,466 $ 4 $ (1 ) $ 42,469 Corporate debt securities 16,378 3 (5 ) 16,376 U.S. government agency securities 8,799 4 — 8,803 Total $ 67,643 $ 11 $ (6 ) $ 67,648 December 31, 2020 Amortized cost Gross unrealized gains Gross unrealized losses Fair Value Commercial paper $ 40,467 $ 11 $ (1 ) $ 40,477 Corporate debt securities 18,634 4 (1 ) 18,637 U.S. government agency securities 8,822 1 — 8,823 Total $ 67,923 $ 16 $ (2 ) $ 67,937

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	3 Months Ended
	Mar. 31, 2021
Property Plant And Equipment [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net consists of the following (in thousands): March 31, December 31, 2021 2020 Laboratory equipment $ 7,829 $ 7,793 Computer and office equipment 769 769 Furniture and fixtures 421 421 Leasehold improvements 9,514 9,514 Construction in progress 516 528 19,049 19,025 Less accumulated depreciation (8,875 ) (8,249 ) $ 10,174 $ 10,776

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2021
Payables And Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consist of the following (in thousands): March 31, December 31, 2021 2020 Payroll related $ 1,436 $ 3,005 Professional fees 454 215 Research and development 577 230 Other 335 323 $ 2,802 $ 3,773

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2021
Equity [Abstract]
Schedule of Shares of Common Stock Reserved for Future Issuance	The Company has reserved for future issuance the following shares of common stock related to the potential exercise of Pre-Funded Warrants, exercise of stock options, and the employee stock purchase plan: March 31, 2021 Common stock issuable under pre-funded warrants 2,548,117 Options to purchase common stock 1,663,868 Employee Stock Purchase Plan 708,433 Total 4,920,418

Equity-based Compensation and_2

Equity-based Compensation and Equity Incentive Plans (Tables)	3 Months Ended
	Mar. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Stock Option Activity	The following table summarizes stock option activity during the three months ended March 31, 2021 Stock options outstanding Weighted average Weighted remaining Aggregate average contractual intrinsic Number of exercise term value (a) options price (in years) (in thousands) Outstanding at December 31, 2020 3,343,836 $ 6.00 8.4 $ 399 Granted 1,331,478 3.49 — Exercised (216 ) 1.70 — Cancelled/Forfeited (97,981 ) 8.25 45 Outstanding at March 31, 2021 4,577,117 5.23 8.7 2,829 Vested or expected to vest at March 31, 2021 4,577,117 5.23 8.7 2,829 Exercisable at March 31, 2021 1,527,574 8.57 7.5 $ 566 (a) The aggregate intrinsic value is calculated as the difference between the exercise price of the options and the fair market value of the underlying common stock for the options that were in the money at March 31, 2021 and December 31, 2020. 2,966,180 and 970,826 options were in the money at March 31, 2021 and December 31, 2020, respectively.
Schedule of Restricted Common Stock Activity	The following table shows restricted stock activity during the three months ended March 31, 2021: Restricted stock awards Weighted average grant date Number of fair value shares (per share) Unvested at December 31, 2020 478,207 $ 2.19 Granted 242,454 3.50 Vested (302,784 ) 2.48 Forfeited (2,719 ) 2.36 Unvested at March 31, 2021 415,158 $ 2.75
Schedule of Equity-based Compensation Expenses	The following table summarizes equity‑based compensation expense within the Company’s consolidated statements of operations and comprehensive loss for the three months ended March 31, 2021 and 2020 (in thousands): Three Months Ended March 31, 2021 2020 Research and development $ 415 $ 441 General and administrative 462 654 $ 877 $ 1,095
Schedule of Equity-based Compensation Expenses by Award Type	The following table summarizes equity‑based compensation expense by type of award for the three months ended March 31, 2021 and 2020 (in thousands): Three Months Ended March 31, 2021 2020 Stock options $ 699 $ 875 Restricted stock awards 172 220 ESPP 6 — $ 877 $ 1,095

Net Loss per Share (Tables)

Net Loss per Share (Tables)	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Schedule of Potentially Common Shares Excluded from Calculation of Net Loss Per share	The following potential common shares, presented based on amounts outstanding at each period end, were excluded from the calculation of the diluted net loss per share attributable to common stockholders for the period indicated because including them would have had an anti-dilutive effect. As of March 31, 2021 2020 Unvested restricted common stock awards 415,158 770,191 Outstanding options to purchase common stock 4,577,117 3,252,459 Potential shares issuable under the ESPP — —

Nature of Business - Additional

Nature of Business - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Cash, cash equivalents, and short-term marketable securities	$ 94,400
Restricted cash	1,097	$ 1,097
Accumulated deficit	$ (245,282)	$ (230,311)

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) - ASU 2017-08	Mar. 31, 2021
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted [true false]	true
Change in accounting principle, accounting standards update, adoption date	Jan. 1, 2021
Change in accounting principle, accounting standards update, immaterial effect [true false]	true

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Schedule of Company's Classified Assets Measured at Fair Value on Recurring Basis (Detail) - Recurring - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair Value Asset Measured On Recurring Basis [Line Items]
Total assets	$ 94,351	$ 100,443
Money market funds
Fair Value Asset Measured On Recurring Basis [Line Items]
Cash and Cash Equivalents	26,703	32,506
Commercial paper
Fair Value Asset Measured On Recurring Basis [Line Items]
Cash and Cash Equivalents	42,469	40,477
U.S. Government Agency Securities and Treasuries
Fair Value Asset Measured On Recurring Basis [Line Items]
Short-term investments	8,803	8,823
Corporate debt securities
Fair Value Asset Measured On Recurring Basis [Line Items]
Cash and Cash Equivalents	16,376	18,637
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value Asset Measured On Recurring Basis [Line Items]
Total assets	35,506	41,329
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Fair Value Asset Measured On Recurring Basis [Line Items]
Cash and Cash Equivalents	26,703	32,506
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Government Agency Securities and Treasuries
Fair Value Asset Measured On Recurring Basis [Line Items]
Short-term investments	8,803	8,823
Significant Other Observable Inputs (Level 2)
Fair Value Asset Measured On Recurring Basis [Line Items]
Total assets	58,845	59,114
Significant Other Observable Inputs (Level 2) | Commercial paper
Fair Value Asset Measured On Recurring Basis [Line Items]
Cash and Cash Equivalents	42,469	40,477
Significant Other Observable Inputs (Level 2) | Corporate debt securities
Fair Value Asset Measured On Recurring Basis [Line Items]
Cash and Cash Equivalents	16,376	18,637
Significant Unobservable Inputs (Level 3)
Fair Value Asset Measured On Recurring Basis [Line Items]
Total assets	0	0
Significant Unobservable Inputs (Level 3) | Money market funds
Fair Value Asset Measured On Recurring Basis [Line Items]
Cash and Cash Equivalents	0	0
Significant Unobservable Inputs (Level 3) | Commercial paper
Fair Value Asset Measured On Recurring Basis [Line Items]
Cash and Cash Equivalents	0	0
Significant Unobservable Inputs (Level 3) | U.S. Government Agency Securities and Treasuries
Fair Value Asset Measured On Recurring Basis [Line Items]
Short-term investments	0	0
Significant Unobservable Inputs (Level 3) | Corporate debt securities
Fair Value Asset Measured On Recurring Basis [Line Items]
Cash and Cash Equivalents	$ 0	$ 0

Available-for-Sale Investment_2

Available-for-Sale Investments - Summary of Available-for-Sale Securities Held (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 67,643	$ 67,923
Gross unrealized gains	11	16
Gross unrealized losses	(6)	(2)
Fair Value	67,648	67,937
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	42,466	40,467
Gross unrealized gains	4	11
Gross unrealized losses	(1)	(1)
Fair Value	42,469	40,477
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	16,378	18,634
Gross unrealized gains	3	4
Gross unrealized losses	(5)	(1)
Fair Value	16,376	18,637
U.S. government agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	8,799	8,822
Gross unrealized gains	4	1
Fair Value	$ 8,803	$ 8,823

Available-for-Sale Investment_3

Available-for-Sale Investments - Additional Information (Detail) $ in Millions	Mar. 31, 2021USD ($)InvestmentSecurity	Dec. 31, 2020USD ($)Investment
Investments Debt And Equity Securities [Abstract]
Number of investments in unrealized loss position	9	8
Number of investments in unrealized loss position, more than twelve months	0	0
Aggregate fair value of securities in unrealized loss position | $	$ 28.8	$ 20.1
Number of securities with other than temporary impairment | Security	0

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 19,049	$ 19,025
Less accumulated depreciation	(8,875)	(8,249)
Property and equipment, net	10,174	10,776
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	7,829	7,793
Computer and Office Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	769	769
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	421	421
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	9,514	9,514
Construction in Progress
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 516	$ 528

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Payroll related	$ 1,436	$ 3,005
Professional fees	454	215
Research and development	577	230
Other	335	323
Total accrued expenses	$ 2,802	$ 3,773

Stockholders Equity - Additiona

Stockholders Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended
	Jun. 30, 2019	Mar. 31, 2021
Common Stock
Class Of Stock [Line Items]
Sale of common stock, shares	6,340,771
Pre-Funded Warrants
Class Of Stock [Line Items]
Warrants to purchase shares of common stock	2,548,117
Warrants exercise price per share	$ 9
Warrants exercise price per share paid at closing of offering	8.99
Ginkgo Bioworks, Inc.
Class Of Stock [Line Items]
Sale of stock, price per share	$ 9
Proceeds from issuance of common stock and pre-funded warrants	$ 79.9
Ginkgo Bioworks, Inc. | Common Stock
Class Of Stock [Line Items]
Sale of common stock, shares	6,340,771
Ginkgo Bioworks, Inc. | Pre-Funded Warrants
Class Of Stock [Line Items]
Warrants exercised		0
Ginkgo Bioworks, Inc. | Pre-Funded Warrants
Class Of Stock [Line Items]
Warrants to purchase shares of common stock	2,548,117
Warrants exercise price per share	$ 9
Warrants exercise price per share paid at closing of offering	$ 8.99
Cowen and Company, LLC | ATM
Class Of Stock [Line Items]
Sale of common stock, shares		2,447,211
Proceeds from issuance of common stock, net of issuance costs		$ 8.1

Stockholders Equity - Schedule

Stockholders Equity - Schedule of Shares of Common Stock Reserved for Future Issuance (Detail)	Mar. 31, 2021shares
Class Of Stock [Line Items]
Total Shares of Common Stock Reserved for Future Issuance	4,920,418
Employee Stock Purchase Plan
Class Of Stock [Line Items]
Total Shares of Common Stock Reserved for Future Issuance	708,433
Options To Purchase Common Stock
Class Of Stock [Line Items]
Total Shares of Common Stock Reserved for Future Issuance	1,663,868
Common Stock Issuable Under Pre-Funded Warrants
Class Of Stock [Line Items]
Total Shares of Common Stock Reserved for Future Issuance	2,548,117

Equity-based Compensation and_3

Equity-based Compensation and Equity Incentive Plans - Additional Information (Detail) - USD ($)	Jan. 01, 2021	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercised to purchase shares of common stock under ESPP		216
Employee unrecognized compensation expense		$ 6,900,000
Employee unrecognized compensation cost, period of recognition		2 years 9 months 18 days
Equity-based compensation expense		$ 877,000	$ 1,095,000
Restricted Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee unrecognized compensation expense		$ 1,100,000
Employee unrecognized compensation cost, period of recognition		3 years 9 months 18 days
Equity-based compensation expense		$ 172,000	220,000
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in number of shares available for issuance (in shares)	381,832
Options exercised to purchase shares of common stock under ESPP		19,061
Equity-based compensation expense		$ 6,000	$ 0
Plan 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in number of shares available for issuance (in shares)	1,909,163

Equity-based Compensation and_4

Equity-based Compensation and Equity Incentive Plans - Schedule of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Outstanding Beginning balance, Number of options	3,343,836
Granted, Number of options	1,331,478
Exercised, Number of options	(216)
Cancelled/Forfeited, Number of options	(97,981)
Outstanding Ending balance, Number of options	4,577,117	3,343,836
Number of options, Vested or expected to vest	4,577,117
Number of options, Exercisable	1,527,574
Beginning balance, Weighted-average price	$ 6
Granted, Weighted-average price	3.49
Exercised, Weighted-average price	1.70
Cancelled/Forfeited, Weighted-average price	8.25
Ending balance, Weighted-average price	5.23	$ 6
Weighted-average price Vested or expected to vest	5.23
Weighted-average price, Exercisable	$ 8.57
Outstanding, weighted average remaining contractual term (Year)	8 years 8 months 12 days	8 years 4 months 24 days
Weighted average remaining contractual term, Vested or expected to vest	8 years 8 months 12 days
Weighted average remaining contractual term, Exercisable	7 years 6 months
Beginning balance, Aggregate Intrinsic value	$ 399
Cancelled/Forfeited, Aggregate Intrinsic value	45
Ending balance, Aggregate Intrinsic value	2,829	$ 399
Aggregate Intrinsic value, Vested or expected to vest at March 31, 2021	2,829
Aggregate Intrinsic value, Exercisable at March 31, 2021	$ 566

Equity-based Compensation and_5

Equity-based Compensation and Equity Incentive Plans - Schedule of Stock Option Activity (Parenthetical) (Detail) - shares	Mar. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price And Additional Disclosures [Abstract]
Number of options in money	2,966,180	970,826

Equity-based Compensation and_6

Equity-based Compensation and Equity Incentive Plans - Schedule of Restricted Common Stock Activity (Detail) - Restricted Common Stock	3 Months Ended
	Mar. 31, 2021$ / sharesshares
Beginning balance, Number of unvested shares/units | shares	478,207
Granted, Number of shares/units | shares	242,454
Vested, Number of shares/units | shares	(302,784)
Forfeited, Number of shares/units | shares	(2,719)
Ending balance, Number of unvested shares/units | shares	415,158
Beginning balance, Unvested Grant date fair value | $ / shares	$ 2.19
Granted, Grant date fair value | $ / shares	3.50
Vested, Grant date fair value | $ / shares	2.48
Forfeited, Grant date fair value | $ / shares	2.36
Ending balance, Unvested Grant date fair value | $ / shares	$ 2.75

Equity-based Compensation and_7

Equity-based Compensation and Equity Incentive Plans - Schedule of Equity-based Compensation Expenses (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense	$ 877	$ 1,095
Research and Development Expense
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense	415	441
General and Administrative Expense
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense	$ 462	$ 654

Equity-based Compensation and_8

Equity-based Compensation and Equity Incentive Plans - Schedule of Equity-based Compensation Expenses by Award Type (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense	$ 877,000	$ 1,095,000
ESPP
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense	6,000	0
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense	699,000	875,000
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Equity-based compensation expense	$ 172,000	$ 220,000

Collaboration Agreements - Addi

Collaboration Agreements - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended
	Jun. 30, 2019	Mar. 31, 2021	Mar. 31, 2020
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Recognition of revenue			$ 100,000
Ginkgo Collaboration
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Prepayment to related party for collaboration agreement	$ 30,000,000
Related party transaction collaboration agreement, initial term	5 years
Current pre-paid research and development		$ 5,100,000
Non-current pre-paid research and development		7,600,000
AbbVie Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Recognition of revenue		0	$ 100,000
Current deferred revenue		$ 0
AbbVie Agreement | IBDCo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration in research and development		54 months

Net Loss per Share - Additional

Net Loss per Share - Additional Information (Detail)	1 Months Ended
	Jun. 30, 2019$ / sharesshares
Common Stock
Number of shares sold | shares	6,340,771
Pre-Funded Warrants
Warrants to purchase shares of common stock | shares	2,548,117
Warrants exercise price per share | $ / shares	$ 9
Warrants exercise price per share paid at closing of offering | $ / shares	$ 8.99

Net Loss per Share - Schedule o

Net Loss per Share - Schedule of Potentially Common Shares Excluded from Calculation of Net Loss Per share (Detail) - shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Unvested Restricted Common Stock Awards
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Common Shares Excluded from Calculation of Net Loss Per share	415,158	770,191
Options To Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially Common Shares Excluded from Calculation of Net Loss Per share	4,577,117	3,252,459

Related-Party Transactions - Ad

Related-Party Transactions - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Jun. 30, 2019	Mar. 31, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
Common stock, outstanding		40,873,526	38,183,273
Ginkgo Bioworks, Inc.
Related Party Transaction [Line Items]
Common stock, outstanding		6,340,771
Prepayment to related party for collaboration agreement	$ 30
Related party transaction collaboration agreement, initial term	5 years
Current Pre-Paid Research and Development		$ 5.1
Non Current Pre-Paid Research and Development		7.6
Prepaid research and development expenses		$ 0.9

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - Subsequent Event - Underwritten Public Offering $ / shares in Units, $ in Millions	1 Months Ended
	Apr. 30, 2021USD ($)$ / sharesshares
Subsequent Event [Line Items]
Sale of common stock, shares | shares	11,500,000
Sale of stock, price per share | $ / shares	$ 3
Net proceeds from the offering | $	$ 32.6