Galecto (GLTO) 10-K 29 Mar 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Mar. 25, 2021	Nov. 02, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-39655
Entity Registrant Name	GALECTO, INC.
Entity Central Index Key	0001800315
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	37-1957007
Entity Address, Address Line One	Ole Maaloes Vej 3
Entity Address, Address Line Two	DK-2200
Entity Address, City or Town	Copenhagen N
Entity Address, Country	DK
City Area Code	+45
Local Phone Number	70 70 52 10
Title of 12(b) Security	Common Stock, par value $0.00001 per share
Trading Symbol	GLTO
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		25,261,832
Entity Public Float			$ 246.3
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
ICFR Auditor Attestation Flag	false
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE The registrant intends to file a definitive proxy statement pursuant to Regulation 14A relating to the 2021 Annual Meeting of Stockholders within 120 days of the end of the registrant’s fiscal year ended December 31, 2020. Portions of such definitive proxy statement are incorporated by reference into Part II and Part III of this Annual Report on Form 10-K to the extent stated herein.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 163,582	$ 11,294
Prepaid expenses and other current assets	5,713	5,117
Receivable on issuance of series C convertible preferred stock or Series C preferred stock		39,700
Total current assets	169,295	56,080
Restricted cash	254	231
Other assets - noncurrent	1,162
Operating lease right-of-use asset	885	298
Total assets	171,596	56,609
Current liabilities
Accounts payable	2,851	3,329
Accrued expenses and other current liabilities	2,715	4,598
Total current liabilities	5,566	7,927
Operating lease liabilities, net of current portion	541	211
Total liabilities	6,107	8,138
Commitments and contingencies (Note 8)
Convertible preferred stock
Total convertible preferred stock		119,619
Stockholders’ equity
Preferred stock, par value of $0.00001 per share; 10,000,000 shares authorized at December 31, 2020, no shares authorized at December 31, 2019; no shares issued or outstanding as of December 31, 2020
Additional paid-in capital	269,175	826
Accumulated deficit	(104,360)	(69,523)
Accumulated other comprehensive income (loss)	674	(2,451)
Total stockholders’ equity	165,489	(71,148)
Total liabilities and stockholders’ equity	$ 171,596	56,609
Series C Convertible Preferred Stock
Current assets
Receivable on issuance of series C convertible preferred stock or Series C preferred stock		39,669
Convertible preferred stock
Total convertible preferred stock		106,205
Series B Convertible Preferred Stock
Convertible preferred stock
Total convertible preferred stock		$ 13,414

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Preferred stock, par value	$ 0.00001	$ 0.00001
Preferred stock, authorized	10,000,000	0
Preferred stock, issued	0
Preferred stock, outstanding	0
Common stock, par value	$ 0.00001	$ 0.00001
Common stock, authorized	300,000,000	5,350,404
Common stock, issued	25,261,832	259,966
Common stock, outstanding	25,261,832	259,966
Series B Convertible Preferred Stock
Convertible preferred stock, par value	$ 0.00001	$ 0.00001
Convertible preferred stock, authorized	0	684,068
Convertible preferred stock, issued	0	684,068
Convertible preferred stock, outstanding	0	684,068
Series C Convertible Preferred Stock
Convertible preferred stock, par value	$ 0.00001	$ 0.00001
Convertible preferred stock, authorized	0	4,133,479
Convertible preferred stock, issued	0	4,125,056
Convertible preferred stock, outstanding	0	4,125,056
Series D Convertible Preferred Stock
Convertible preferred stock, par value	$ 0.00001	$ 0.00001
Convertible preferred stock, authorized	0	0
Convertible preferred stock, issued	0	0
Convertible preferred stock, outstanding	0	0

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating expenses
Research and development	$ 24,627	$ 19,738
Purchased in-process research and development		16,788
General and administrative	9,010	2,445
Total operating expenses	33,637	38,971
Loss from operations	(33,637)	(38,971)
Other income (expense), net
Foreign exchange transaction gain (loss), net	(1,200)	551
Fair value adjustments on preferred stock tranche obligations and note tranche and derivative obligations		1,913
Total other income (expense), net	(1,200)	2,464
Net loss	(34,837)	(36,507)
Cumulative dividends on convertible preferred stock		(5,560)
Net loss attributable to common stockholders	$ (34,837)	$ (42,067)
Net loss per common share, basic and diluted	$ (7.62)	$ (161.82)
Weighted-average number of shares used in computing net loss per common share, basic and diluted	4,572,702	259,966
Other comprehensive loss
Net loss	$ (34,837)	$ (36,507)
Currency translation gain (loss)	3,125	(806)
Total comprehensive loss	$ (31,712)	$ (37,313)

Consolidated Statements of Conv

Consolidated Statements of Convertible Preferred Stock and Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Series B Convertible Preferred Stock	Series C Convertible Preferred Stock	Series D Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2018	$ (33,835)					$ 826	$ (33,017)	$ (1,644)
Beginning balance (in shares) at Dec. 31, 2018		684,068	1,973,203
Beginning balance at Dec. 31, 2018		$ 13,414	$ 51,081
Beginning balance (in shares) at Dec. 31, 2018					259,966
Issuance of preferred stock			$ 15,624
Issuance of preferred stock (in shares)			610,098
Commitment to the issuance of Series C preferred stock			$ 39,500
Commitment to the issuance of Series C preferred stock (in shares)			1,541,755
Currency translation gain (loss)	(806)							(806)
Net loss	(36,507)						(36,507)
Ending balance at Dec. 31, 2019	(71,148)					826	(69,523)	(2,451)
Ending balance (in shares) at Dec. 31, 2019		684,068	4,125,056
Ending balance at Dec. 31, 2019	119,619	$ 13,414	$ 106,205
Ending balance (in shares) at Dec. 31, 2019					259,966
Issuance of preferred stock				$ 61,359
Issuance of preferred stock (in shares)				2,368,118
Issuance of common stock in connection with initial public offering, net of issuance costsof $2,797	86,360					86,360
Issuance of common stock in connection with initial public offering, net of issuance costs (in shares)					6,342,207
Conversion of convertible preferred stock into common stock	180,978	$ (13,414)	$ (106,205)	$ (61,359)		180,978
Conversion of convertible preferred stock into common stock (in shares)		(684,068)	(4,125,056)	(2,368,118)	18,658,643
Stock-based compensation expense	1,009					1,009
Exercise of stock options	$ 2					2
Exercise of stock options (in shares)	1,016				1,016
Currency translation gain (loss)	$ 3,125							3,125
Net loss	(34,837)						(34,837)
Ending balance at Dec. 31, 2020	$ 165,489					$ 269,175	$ (104,360)	$ 674
Ending balance (in shares) at Dec. 31, 2020					25,261,832

Consolidated Statements of Co_2

Consolidated Statements of Convertible Preferred Stock and Changes in Stockholders' Equity (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Series D Convertible Preferred Stock
Preferred stock issuance costs, net	$ 2,840
Initial Public Offering
Common stock issuance costs, net	$ 2,114

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net loss	$ (34,837)	$ (36,507)
Adjustment to reconcile net loss to net cash used in operating activities:
Purchased in-process research and development		16,788
Stock-based compensation	982
Fair value adjustments on preferred stock tranche obligations and note tranche and derivative obligations		(1,913)
Amortization of right of use lease asset	188	111
Accretion of lease liability	55
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(596)	(1,220)
Accounts payable	(477)	1,938
Accrued expenses and other current liabilities	(2,143)	1,606
Other assets, noncurrent	(1,162)
Operating lease liabilities, noncurrent	(213)	(129)
Net cash used in operating activities	(38,203)	(19,326)
Cash flows from investing activities
Merger acquisition costs, net of cash received		(326)
Net cash used in investing activities		(326)
Cash flows from financing activities
Proceeds from the issuance of common stock in connection with initial public offering	88,473
Initial public offering issuance costs	(2,114)
Proceeds from exercise of stock options	2
Net cash provided by financing activities	187,389
Net increase (decrease) in cash and cash equivalents	149,186	(19,652)
Effect of exchange rate changes on cash and cash equivalents	3,125	46
Cash, cash equivalents and restricted cash, beginning of year	11,525	31,131
Cash, cash equivalents and restricted cash, end of year	163,836	11,525
Components of cash, cash equivalents, and restricted cash
Cash and cash equivalents	163,582	11,294
Restricted cash	254	231
Cash, cash equivalents and restricted cash, end of year	163,836	11,525
Supplemental disclosures of noncash activities:
Operating lease liability arising from obtaining right-of-use assets	713	391
Cumulative effect of change in accounting principle—adoption of ASC 842, Leases		15
Series C Convertible Preferred Stock
Cash flows from financing activities
Proceeds from issuance of preferred stock	39,669
Supplemental disclosures of noncash activities:
Issuance of Series C convertible preferred stock in connection with acquisition		$ 15,624
Series D Convertible Preferred Stock
Cash flows from financing activities
Proceeds from issuance of preferred stock	64,199
Series D preferred stock issuance costs	$ (2,840)

Description of Business, Organi

Description of Business, Organization and Liquidity	12 Months Ended
	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business, Organization and Liquidity	1. DESCRIPTION OF BUSINESS, ORGANIZATION AND LIQUIDITY Business Galecto, Inc., together with its consolidated subsidiaries, (the “Company” or “Galecto”), is a clinical-stage biotechnology company developing therapeutics that are designed to target the biological processes that lie at the heart of fibrosis and impact a broad range of fibrotic and related diseases, including cancer. The Company’s initial focus is on the development of small-molecule inhibitors of galectin-3 and lysyl oxidase-like 2, or LOXL2, which play key roles in regulating fibrosis and cancer. Reorganization and purchase of PharmAkea, Inc. Galecto, Inc. was incorporated in Delaware in October 2019. On December 31, 2019, as part of an integrated transaction, Galecto, Inc., Galecto Biotech AB, a Swedish operating company, and PharmAkea, Inc., or PharmAkea, consummated a purchase agreement and plan of merger by and among Galecto, Inc., Galecto Biotech AB and PharmAkea, or the Purchase, whereby Galecto, Inc. (i) acquired the shareholdings of Galecto Biotech AB via a one-for-one exchange of equity between Galecto, Inc. and the shareholders of Galecto Biotech AB in a common control reorganization, and (ii) acquired PharmAkea in principally an all-stock transaction. As of December 31, 2020, the Company’s wholly owned subsidiaries were PharmAkea, Galecto Securities Corporation and Galecto Biotech AB, and Galecto Biotech ApS, a Danish operating company, was Galecto Biotech AB’s wholly owned subsidiary. The consolidated balance sheet as of December 31, 2020 and 2019 is that of Galecto, Inc. The consolidated statements of operations and comprehensive loss, convertible preferred shares and stockholders’ deficit and cash flows for the year ended December 31, 2020 are that of Galecto, Inc. and for the year ended December 31, 2019 are principally that of Galecto Biotech AB together with that of Galecto, Inc. with the respect to the purchase of PharmAkea. Risks and uncertainties The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations and the need to obtain additional financing. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval, prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance reporting capabilities. The Company’s product candidates are in development. 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 government 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 significant revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its employees and consultants. Liquidity and management plans Since inception, the Company has devoted substantially all its efforts to business planning, research and development, recruiting management and technical staff and raising capital and has financed its operations primarily through the issuance of redeemable convertible preferred shares, debt financings and, most recently, the Company’s initial public offering, or IPO. As of December 31, 2020, the Company had an accumulated deficit of $104.4 million, from recurring losses since inception in 2011. The Company has incurred recurring losses and has no sales as no products have obtained the necessary regulatory approval in order to market products. The Company expects to continue to incur losses as a result of costs and expenses related to the Company’s clinical development and corporate general and administrative activities. The Company had negative cash flows from operating activities during the year ended December 31, 2020 and 2019 of $38.2 million and $19.3 million, respectively, and current projections indicate that the Company will have continued negative cash flows for the foreseeable future as it continues to develop its product candidates. Net losses incurred for the years ended December 31, 2020 and 2019 amounted to $34.8 million and $36.5 million, respectively. At December 31, 2020, the Company’s cash and cash equivalents amounted to $163.6 million and will be sufficient to continue funding our development activities into 2024 based on the Company’s operating plan. In addition, at December 31, 2020, current assets amounted to $169.3 million and current liabilities amounted to $5.6 million. At December 31, 2019, the Company’s cash and cash equivalents amounted to $11.3 million, current assets amounted to $56.1 million and current liabilities amounted to $7.9 million. In the future, the Company will consider the following ways to fund its operations including: (1) raising additional capital through equity and/ or debt financings; (2) new commercial relationships to help fund future clinical trial costs (i.e. licensing and partnerships); (3) reducing spending on one or more research and development programs by discontinuing development; and/or (4) restructuring operations to change its overhead structure. The Company’s future liquidity needs, and ability to address those needs, will largely be determined by the success of its product candidates and key development and regulatory events and its decisions in the future. Coronavirus pandemic The coronavirus disease 2019, or COVID-19, pandemic, which began in December 2019 and has spread worldwide, has caused many governments to implement measures to slow the spread of the outbreak through quarantines, travel restrictions, heightened border scrutiny and other measures. The outbreak and government measures taken in response have also had a significant impact, both directly and indirectly, on businesses and commerce, as worker shortages have occurred; supply chains have been disrupted; facilities and production have been suspended; and demand for certain goods and services, such as medical services and supplies, has spiked, while demand for other goods and services, such as travel, has fallen. The future progression of the outbreak and its effects on the Company’s business and operations are uncertain. In response to the impact of COVID-19, the Company has implemented certain measures intended to help the Company manage its impact and position the Company to resume operations quickly and efficiently once these restrictions are lifted, such as executing a work-from-home strategy for administrative functions and operations. The Company continues to monitor the impact of COVID-19 and assess its strategy accordingly. Despite the Company’s implementation of such measures, the actual and perceived impact of the COVID-19 pandemic is changing daily, and its ultimate effect on the Company cannot be predicted. As a result, there can be no assurance that the Company will not experience additional negative impacts associated with COVID-19, which could be significant. The COVID-19 pandemic may negatively impact the Company’s business, financial condition and results of operations by decreasing or delaying the enrollment of patients in the Company’s clinical trials or otherwise causing interruptions or delays in the Company’s programs and services. On March 27, 2020, the United States enacted the Coronavirus Aid, Relief and Economic Security Act, or CARES Act. The CARES Act is an emergency economic stimulus package that includes spending and tax breaks to strengthen the United States economy and fund a nationwide effort to curtail the effect of COVID-19. The CARES Act provides sweeping tax changes in response to the COVID-19 pandemic, some of the more significant provisions include removing certain limitations on the utilization of net operating losses, increasing the loss carryback period for certain losses to five years, increasing the ability to deduct interest expense, and deferring social security payments, as well as amending certain provisions of the previously enacted Tax Cuts and Jobs Act. The Company does not believe the CARES Act will have a material impact on its financial position and results of operations.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of presentation The accompanying consolidated financial statements have been prepared in conformity with U.S. GAAP. Any reference in these notes to applicable guidance is meant to refer to U.S. GAAP, as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB. Principles of consolidation The Company’s consolidated financial statements for 2020 and 2019 include the accounts of Galecto, Inc. and its subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Use of estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect certain reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of expenses during the reporting periods. Significant items subject to such estimates and assumptions include contract research accruals, stock-based compensation expense, the fair value of the Company’s common stock and valuation of the Company’s deferred tax assets. The Company bases its estimates on historical experience and various other assumptions that management believes to be reasonable under the circumstances. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates. Currency and currency translation The consolidated financial statements are presented in U.S. dollars, the Company’s reporting currency. Galecto, Inc., Galecto Securities Corporation and PharmAkea’s functional currency is the U.S. dollar. The functional currency of the Company’s subsidiary Galecto Biotech AB, and its subsidiary Galecto Biotech ApS, is the Euro. Adjustments that arise from exchange rate changes on transactions of each group entity denominated in a currency other than the functional currency are included in other income and expense in the consolidated statements of operations. Assets and liabilities of Galecto Biotech AB and Galecto Biotech ApS recorded in their Euro functional currency are translated into the U.S. dollar reporting currency of the Company at the exchange rate on the balance sheet date. Revenue and expenses of Galecto Biotech AB and Galecto Biotech ApS recorded in their Euro functional currency are translated into the U.S. dollar reporting currency of the Company at the average exchange rate prevailing during the year. Resulting translation adjustments are recorded to other comprehensive income (loss), or OCI. Cash and cash equivalents The Company considers all highly liquid investments with original maturities at the date of purchase of three months or less to be cash equivalents. Cash and cash equivalents are stated at fair value and may include money market funds, U.S. Treasury and U.S. government-sponsored agency securities, corporate debt, commercial paper and certificates of deposit. The Company had money market funds of $142.9 million as of December 31, 2020, which are included in cash and cash equivalents and reported at fair value (Note 3). The Company had no cash equivalents as of December 31, 2019. Restricted cash The Company is required to maintain cash collateral on deposit in a segregated money market bank account, as a condition of its security deposit with one of its banks for the use of corporate credit cards. As of December 31, 2020 and 2019, the Company presented restricted cash in the accompanying consolidated balance sheets of $254,000 and $231,000, respectively. Concentrations of credit risk and off-balance sheet risk The Company maintains its cash in bank deposit and checking accounts that at times exceed insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to any significant credit risk. Fair value of financial instruments Fair value is defined as the price the Company would receive to sell an investment in a timely transaction or pay to transfer a liability in a timely transaction with an independent buyer in the principal market, or in the absence of a principal market, the most advantageous market for the investment or liability. A framework is used for measuring fair value utilizing a three-tier hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). The three levels of the fair value hierarchy are as follows: Level 1 —Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; Level 2 —Quoted prices in markets that are not considered to be active or financial instrument valuations for which all significant inputs are observable, either directly or indirectly; and Level 3 —Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable. Financial instruments are categorized in their entirety based on the lowest level of input that is significant to the fair value measurement. The assessment of the significance of a particular input to the fair value measurement requires judgment and considers factors specific to the investment. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by us in determining fair value is greatest for instruments categorized in Level 3. The Company monitors the availability of inputs that are significant to the measurement of fair value to assess the appropriate categorization of financial instruments within the fair value hierarchy. Changes in economic conditions or model-based valuation techniques may require the transfer of financial instruments from one fair value level to another. In such instances, our policy is to recognize significant transfers between levels at the end of the reporting period. The significance of transfers between levels is evaluated based upon the nature of the financial instrument and size of the transfer relative to total net assets available for benefits. Research and development expenses Research and development costs are expensed as incurred. The Company’s research and development expenses consist primarily of costs incurred for the development of its product candidates and include expenses incurred under agreements with contract manufacturing organizations, or CMOs, contract research organizations, or CROs, investigative sites and consultants to conduct clinical trials and preclinical and non-clinical studies, costs to acquire, develop and manufacture supplies for clinical trials and other studies, salaries and related costs, including stock-based compensation, depreciation and other allocated facility-related and overhead expenses and licensing fees and milestone payments incurred under product license agreements where no alternative future use exists. From time to time, Galecto obtains grants from public and private funds for its research and development projects. The grant income for a given period is recognized as a cost reimbursement and is typically based on the time and the costs that Galecto has spent on the specific project during that period. During the year ended 2019, the Company had two active cost reimbursement grants with Tufts University and with the Innovation Fund of Denmark. The grants provided reimbursement of direct research and development costs. For the year ended December 31, 2019, research and development expenses in the consolidated statements of operations include $388,000 and of grant income cost reimbursement. There was no grant income cost reimbursement for the year ended December 31, 2020. The Company has met the requirements to receive a tax credit in Denmark for losses resulting from research and development costs of up to $4.1 million for the years ended December 31, 2020 and 2019. The tax credit is reported as a reduction to research and development expense in the consolidated statements of operations. For the years ended December 31, 2020 and 2019, research and development expenses include refundable tax credits of $809,000 and $824,000 respectively. Accrued research and development costs Substantial portions of the Company’s preclinical and clinical trials are performed by third-party laboratories, medical centers, CROs and other vendors, or collectively, CROs. These CROs generally bill monthly for services performed, or bill based upon milestone achievement. For preclinical studies, the Company accrues expenses based upon estimated percentage of work completed and the contract milestones remaining. For clinical studies, expenses are accrued based upon the number of patients enrolled and the duration of the study. The Company monitors patient enrollment, the progress of clinical studies and related activities to the extent possible through internal reviews of data reported to the Company by the CROs, correspondence with the CROs and clinical site visits. The Company’s estimates depend on the timeliness and accuracy of the data provided by the CROs regarding the status of each program and total program spending. The Company periodically evaluates the estimates to determine if adjustments are necessary or appropriate based on information it receives. Acquired in-process research and development expenses The Company includes costs to acquire or in-license product candidates in acquired in-process research and development expenses. The Company has acquired the right to develop and commercialize its product candidate PAT-1251, which the Company now refers to as GB2064. These costs are immediately expensed provided that the payments do not also represent processes or activities that would constitute a business as defined under U.S. GAAP or provided that the product candidate has not achieved regulatory approval for marketing and absent obtaining such approval, has no alternative future use. Leases In February 2016, the FASB established Topic 842, Leases Leases Land Easement Practical Expedient for Transition to Topic 842 Codification Improvements to Topic 842, Leases Targeted Improvements The Company adopted ASU 842 on January 1, 2019 using the modified retrospective method, in which case the cumulative effect of applying the standard would be recognized at the date of initial application. The Company has completed a qualitative and quantitative assessment of its lease portfolio, in which the standard had a material impact on the consolidated balance sheets but did not have an impact on the consolidated statements of operations and comprehensive loss. Upon adoption, the Company recognized lease liabilities of $379,000 based on the present value of the remaining minimum rental payments under current leasing standards for the Company’s existing operating leases. The corresponding ROU assets of $379,000 recognized upon adoption are net of deferred rent. ASU 842 provides a number of optional practical expedients in transition. The Company elected the package of practical expedients that permit lessees not to reassess under ASU 842 prior conclusions about lease identification, lease classification and initial direct costs. The Company did not elect the use-of-hindsight or the practical expedient pertaining to land easements; the latter not being applicable to the Company. The new standard also provides practical expedients for an entity’s ongoing accounting. The Company elected the short-term lease recognition exemption for all leases that qualify. This means, for those leases that qualify, ROU assets or lease liabilities will not be recognized, and this includes not recognizing ROU assets or lease liabilities for existing short-term leases of those assets in transition. The Company also elected the practical expedient to not separate lease and non-lease components for office leases. At inception of a contract, the Company determines whether an arrangement is or contains a lease. For all leases, the Company determines the classification as either operating leases or finance leases. Operating leases are included in Operating lease right-of-use assets and Operating lease liabilities in the Company’s consolidated balance sheets. Lease recognition occurs at the commencement date and lease liability amounts are based on the present value of lease payments over the lease term. The lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. If a lease does not provide information to determine an implicit interest rate, the Company uses the Company’s incremental borrowing rate in determining the present value of lease payments. ROU assets represent the right to use an underlying asset for the lease term, and lease liabilities represent the obligation to make lease payments under the lease. ROU assets also include any lease payments made prior to the commencement date and exclude lease incentives received. Operating lease expense is recognized on a straight-line basis over the lease term. The depreciable life of assets and leasehold improvements are limited by the expected lease term, unless there is a transfer of title or purchase option reasonably certain of exercise. Lease agreements with both lease and non-lease components, are generally accounted for together as a single lease component. Refer to Note 6 for further details. Convertible preferred stock The Company classifies convertible preferred stock outside of stockholders’ deficit on its consolidated balance sheet as the requirements of triggering a deemed liquidation event are not within the Company’s control. In the event of a deemed liquidation event, the proceeds from the event are distributed in accordance with liquidation preferences (see Note 9). The Company records the issuance of convertible preferred stock at the issuance price less related issuance costs and less any discount arising on allocation of proceeds to one or more derivative features. Immediately prior to consummation of the Company’s IPO, all outstanding shares of the Company’s convertible preferred stock were converted into shares of common stock. Equity-based compensation The Company accounts for stock options granted in accordance with ASC 718, Compensation-Stock Compensation All share-based awards granted are measured based on the fair value on the date of the grant and compensation expense is recognized with respect to those awards over the requisite service period, which is generally the vesting period of the respective award. The Company reverses any previously recognized compensation cost associated with forfeited awards in the period the forfeiture occurs. Equity-based compensation expense is classified in the Company’s consolidated statement of operations and comprehensive loss in the same manner in which the award recipients’ payroll costs are classified or in which the award recipients’ service payments are classified. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes model. The following summarizes the inputs used: Expected volatility —The Company estimates its expected stock volatility based on the historical volatility of a publicly traded set of peer companies because we lack company-specific historical and implied volatility information due in part to the limited time in which we have operated as a publicly traded company. We expect to continue to do so until such time as we have adequate historical data regarding the volatility of our traded stock price. Expected term —The expected term of the Company’s stock options has been determined based on the expected time to liquidity. The Company uses the simplified method prescribed by the SEC’s Staff Accounting Bulletin No. 107, Share-Based Payment , to calculate the expected term of options granted because we lack company-specific historical and implied expected term information due in part to the limited time in which we have operated as a publicly traded company. Risk-free interest rate —The risk-free interest rate is based on the implied yield on a U.S. Treasury security at a constant maturity with a remaining term equal to the expected term of the option granted. Dividends —Expected dividend yield is zero because the Company does not pay cash dividends on common shares and does not expect to pay any cash dividends in the foreseeable future. Prior to the IPO, the Company’s board of directors, with input from management, determined the estimated fair value of the common shares as of the date of each incentive share grant considering the Company’s then-most recently available third-party valuation of common shares. Valuations are updated when facts and circumstances indicate that the most recent valuation is no longer valid, such as changes in the stage of development efforts, various exit strategies and their timing, and other scientific developments that could be related to the Company’s valuation, or, at a minimum, annually. Third-party valuations were performed in accordance with the guidance outlined in the American Institute of Certified Public Accountants’ Accounting and Valuation Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation Income taxes Deferred income tax assets and liabilities arise from temporary differences associated with differences between the financial statements and tax basis of assets and liabilities, as measured by the enacted tax rates, which are expected to be in effect when these differences reverse. Valuation allowances are established when necessary to reduce deferred tax assets to the amount expected to be realized. The Company has generated net losses since inception and accordingly has not recorded a provision for income taxes. The Company follows the provisions of ASC 740-10, Uncertainty in Income Taxes, The Company has identified the United States, Denmark and Sweden as its major tax jurisdictions. Refer to Note 12 for further details. Net loss per share Basic net loss per share is computed by dividing the net loss by the weighted-average number of shares of common stock outstanding for the period. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of shares of common stock and dilutive common stock equivalents outstanding for the period, determined using the treasury-stock method and the as if-converted method, for convertible securities, if inclusion of these instruments is dilutive. For the year ended December 31, 2020 and 2019, both methods are equivalent. Basic and diluted net loss per share are described further in Note 13. Segments Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the chief operating decision maker, or CODM, in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s CODM is its chief executive officer. The Company has determined it operates in one segment. Other comprehensive income (loss) OCI is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. The Company’s OCI includes currency translation. Emerging growth company status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012, or JOBS Act. Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act, until such time as those standards apply to private companies. The Company may elect to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it (i) is no longer an emerging growth company or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act. As a result, these financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates. Recently adopted accounting standards In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480) and Derivatives and Hedging (Topic 815): I. Accounting for Certain Financial Instruments with Down Round Features; and II. Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception Distinguishing Liabilities from Equity Prior to January 1, 2019, the Company accounted for leases under ASC 840, Accounting for Leases Leases In June 2018, the FASB issued ASU No. 2018-07, Compensation – Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting Recently issued accounting standards In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments Codification Improvements to Topic 326, Financial Instruments-Credit Losses, Topic 815, Derivatives and Hedging and Topic 825, Financial Instruments During August 2018, the FASB issued ASU No. 2018-13, D isclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement Fair Value Measurement. The amendments are based on the concepts in the FASB Concepts Statement, Conceptual Framework for Financial Reporting—Chapter 8: Notes to Financial Statements In December 2019, the FASB issued ASU No. 2019-12, Simplifying the Accounting for Income Taxes

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. FAIR VALUE MEASUREMENTS Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value are performed in a manner to maximize the use of observable inputs and minimize the use of unobservable inputs. The Company classified its money market funds within Level 1 because their fair values are based on their quoted market prices. The Company had no financial assets or liabilities measured at fair value on a recurring basis as of December 31, 2019. A summary of the assets that are measured at fair value as of December 31, 2020 is as follows (in thousands): Fair Value Measurement at December 31, 2020 Assets: Carrying Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Money market funds ( 1) $ 142,904 $ 142,904 $ — $ — Total $ 142,904 $ 142,904 $ — $ — (1) Money market funds with maturities of 90 days or less at the date of purchase are included within cash and cash equivalents in the accompanying consolidated balance sheets and are recognized at fair value. The Company had a preferred stock tranche obligation (Note 9), or (“Preferred Stock Tranche Obligation”), measured at (Level 3) fair value on a recurring basis of $1.7 million as of December 31, 2018. There were no transfers among Level 1, Level 2 or Level 3 categories in the years ended December 31, 2020 or 2019. The following table provides a reconciliation of the Company’s liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) (in thousands): Preferred Stock Tranche Obligations Balance, December 31, 2018 $ 1,744 Fair value adjustments (1,913 ) Settlement on commitment to purchase Series C preferred stock 169 Balance, December 31, 2019 $ — Preferred stock tranche obligation The Company’s Preferred Stock Tranche Obligation (Note 9) was measured at fair value using an option pricing valuation methodology. The fair value of Preferred Stock Tranche Obligation included inputs not observable in the market and thus represented a Level 3 measurement. The option methodology utilized required inputs based on certain subjective assumptions, including (a) expected stock price volatility, (b) calculation of an expected term, (c) a risk-free interest rate, and (d) expected dividends. This approach resulted in the classification of these securities as Level 3 of the fair value hierarchy. For the year ended December 31, 2019, the Company recognized a $1.9 million nonoperating gain in the statement of operations as fair value adjustments on preferred stock tranche obligations, with respect to changes to the fair value of the Preferred Stock Tranche Obligation. The Company had no Preferred Stock Tranche Obligation as of December 31, 2020.

Purchase of PharmAkea, Inc.

Purchase of PharmAkea, Inc.	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Purchase of PharmAkea, Inc.	4. PURCHASE OF PHARMAKEA, INC. The Purchase was principally an all-stock transaction whereby the Company exchanged 610,098 shares of its Series C-3 preferred stock, or approximately 13% of the shares of the Company subsequently outstanding, for PharmAkea. The Company was determined to be the accounting acquirer, and the Purchase of PharmAkea has been accounted for as an asset acquisition pursuant to Topic 805, Business Combinations The following summarizes the purchase price of the Purchase (in thousands, except share and per share amounts): Value of the shares of Series C preferred stock issued to former PharmAkea stockholders $ 15,625 Cash consideration to non-accredited former PharmAkea stockholders 216 Payments made and Company options issued to former PharmAkea executives pursuant to the terms of the Purchase 583 Transaction costs 978 Purchase price $ 17,402 The total purchase price has been allocated to the assets acquired and liabilities assumed as of December 31, 2019 as follows (in thousands): Purchased in-process research and development—GB2064 $ 16,788 Cash acquired 653 Trade liabilities assumed (39 ) Purchase price $ 17,402 Purchased in-process research and development with respect to GB2064 is charged directly to expense in the consolidated statements of operations on the purchase date, December 31, 2019. The value of GB2064 consists primarily of technology associated with the drug compound that the Company plans to advance in clinical development but as of the date of the Purchase was in early stages of clinical development, had not received regulatory approval to commercialize and, thus, had no alternative future use. The fair value of GB2064 was determined under a multi-period excess earnings method, or MPEEM, and income approach and a variation of the discounted cash flow method used to measure the fair value of intangible assets. The MPEEM fair value is a risk-adjusted assessment of the market potential of GB2064 for the treatment of Myelofibrosis, discounted using a calculated market participant weighted average cost of capital of 45%.

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	12 Months Ended
	Dec. 31, 2020
Prepaid Expense And Other Assets Current [Abstract]
Prepaid Expenses and Other Current Assets	5. PREPAID EXPENSES AND OTHER CURRENT ASSETS Prepaid expenses and other current assets consist of the following (in thousands): December 31, 2020 2019 Research and development tax credit receivable $ 1,808 $ 827 Prepaid insurance costs 1,642 — Contract research and development costs 1,620 3,344 Value-added tax refund receivable 401 253 Grant reimbursement receivable — 379 Other 242 314 Total prepaid expenses and other current assets $ 5,713 $ 5,117

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	6. LEASES On January 1, 2019, the Company adopted ASC 842 using the modified retrospective transition approach allowed under ASU 2018-11 which releases companies from presenting comparative periods and related disclosures under ASC 842 and requires a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption (Note 2). The Company is party to three operating leases for office and laboratory space. The Company’s finance leases are immaterial both individually and in the aggregate. The Company has elected to apply the short-term lease exception to all leases of one year or less. Rent expense for years ended December 31, 2020 and 2019 was $250,000 and $222,000, respectively. The Company has an operating lease for its corporate headquarters in Copenhagen, Denmark for office space that expires in October 2021. In June 2020, the Company amended the related lease agreement to include an additional 1,300 square feet of office space. The Company also has a lease agreement for office space in London, United Kingdom, that expires August 2022 and has a renewal option and a lease agreement for office space in Gothenburg, Sweden, that expires in September 2022. The Company had an operating lease in London, United Kingdom for office space that expired in August 2020 and an operating lease in Quebec, Canada for office space that expired in July 2020. Quantitative information regarding the Company’s leases for the years ended December 31, 2020 and 2019 is as follows (in thousands): Year Ended December 31, Lease Cost: 2020 2019 Operating lease cost $ 213 $ 129 Other Information: Operating cash flows paid for amounts included in the measurement of lease liabilities $ 213 $ 129 Operating lease liabilities arising from obtaining right-of-use assets $ 713 $ 391 Weighted average remaining lease term (years) 2.8 4.2 Weighted average discount rate 8.0 % 8.0 % As most of the Company’s leases do not provide an implicit rate, the Company used its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The Company used the incremental borrowing rate on January 1, 2019 for operating leases that commenced prior to that date. Future lease payments under noncancelable leases are as follows at December 31, 2020 (in thousands): Future Lease Payments Operating Leases 2021 $ 434 2022 325 2023 145 2024 121 2025 — Total lease payments 1,025 Less: imputed interest (110 ) Total lease liabilities $ 915 The Company is proceeding with the option to renew its corporate headquarters in Copenhagen, Denmark for office space. The renewal option will expire in October 2024 and additional lease payments of $288,000 are included in the future lease payments above. In January 2021, the Company entered into an operating lease agreement in Stevenage, United Kingdom, for laboratory space. The lease agreement has a three-year term, which expires in January 2024 and has a renewal option. The total lease payments due during the term of the lease are $179,000 and are not included in the future lease payments above.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2020
Payables And Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	7. ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES Accrued expenses and other current liabilities consist of the following (in thousands): December 31, 2020 2019 Employee compensation costs $ 1,031 $ 113 Contract research and development costs 967 3,493 Lease liabilities 374 87 Costs related to the Purchase of PharmAkea — 838 Other liabilities 343 67 Total accrued expenses and other current liabilities $ 2,715 $ 4,598

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	8. COMMITMENTS AND CONTINGENCIES Lease commitments The Company’s commitments related to lease agreements are disclosed in Note 6. Legal proceedings From time to time, the Company may be party to litigation arising in the ordinary course of its business. The Company was not subject to any material legal proceedings during the years ended December 31, 2020 and 2019, and, to its knowledge, no material legal proceedings are currently pending or threatened. Indemnification agreements The Company, as permitted under Delaware law and in accordance with its certification of incorporation and bylaws and pursuant to indemnification agreements with certain of its officers and directors, indemnifies its officers and directors for certain events or occurrences, subject to certain limits, which the officer or director is or was serving at the Company’s request in such capacity. The Company enters into certain types of contracts that contingently requires the Company to indemnify various parties against claims from third parties. These contracts primarily relate to (i) the Company’s bylaws, under which the Company must indemnify directors and executive officers, and may indemnify other officers and employees, for liabilities arising out of their relationship, (ii) contracts under which the Company must indemnify directors and certain officers and consultants for liabilities arising out of their relationship, and (iii) procurement, service or license agreements under which the Company may be required to indemnify vendors, service providers or licensees for certain claims, including claims that may be brought against them arising from the Company’s acts or omissions with respect to the Company’s products, technology, intellectual property or services. From time to time, the Company may receive indemnification claims under these contracts in the normal course of business. In the event that one or more of these matters were to result in a claim against the Company, an adverse outcome, including a judgment or settlement, may cause a material adverse effect on the Company’s future business, operating results or financial condition. It is not possible to estimate the maximum amount potentially payable under these contracts since the Company has no history of prior indemnification claims and the unique facts and circumstances involved in each particular claim will be determinative.

Convertible Preferred Stock

Convertible Preferred Stock	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Convertible Preferred Stock	9. CONVERTIBLE PREFERRED STOCK During the fiscal year ended December 31, 2018, Galecto Biotech AB concluded a Series C financing involving a combination of existing shareholders and new investors, or Series C Financing. At closing, Galecto Biotech AB issued 1,284,795 Series C-2 shares in exchange for $34.5 million in net proceeds. The Series C Financing further allowed for milestone closings in the event of certain development milestones, whereby purchasers of Series C preferred stock had the option to purchase additional shares of Series C preferred stock, or the Preferred Stock Tranche Obligation. The milestones were achieved in 2019 and, in December 2019, Series C investors committed to the sale and issuance of 1,199,143 Series C-4 preferred shares and 342,612 Series C-5 preferred shares of the Company for a total of $39.7 million. As a result of the issuance of the Series C-4 preferred stock and Series C-5 preferred, the Company issued a total of 198,770 additional Series C-3 preferred shares to former PharmAkea shareholders pursuant to the terms of the Purchase (See Note 4). The sale and issuance of the Series C-4 preferred stock and Series C-5 preferred were committed to in December 2019 and are included in the consolidated balance sheet as of December 31, 2019 with a corresponding $39.7 million receivable for the proceeds included within current assets in the consolidated balance sheet as of December 31, 2019. The issuance of additional Series C-3 preferred stock with respect to the Purchase of PharmAkea stemming from the sale and issuance of the Series C-4 preferred stock and Series C-5 preferred stock is also included in the consolidated balance sheet as of December 31, 2019 and comprises an element of the purchase price for the Purchase. The $39.7 million proceeds were received, and shares issued in January 2020. In September 2020, the Company sold and issued 2,368,118 shares of Series D preferred stock for gross proceeds of $64.2 million, or $61.4 million net of $2.8 million in issuance costs. The Series D preferred stock ranked on-par with the Company’s Series C preferred stock with respect to dividends and in liquidation as disclosed in Note 9 to the Company’s annual consolidated financial statements for the years ended December 31, 2019 and 2018 included in the final prospectus for the Company’s IPO filed pursuant to Rule 424(b)(4) under the Securities Act with the SEC on October 30, 2020. Immediately prior to consummation of the IPO, all outstanding shares of the Company’s Series B, Series C and Series D convertible preferred stock were converted into 18,658,643 shares of common stock.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2020
Stockholders Equity Note [Abstract]
Stockholders' Equity	10. STOCKHOLDERS’ EQUITY Common and preferred stock In October 2020, the Company completed its IPO selling an aggregate of 6,342,207 shares of common stock at $15.00 per share, which included 675,540 shares that represented the partial exercise in November 2020 of an option to purchase additional shares granted to the underwriters in connection with the IPO. The offering resulted in $86.3 million of net proceeds to the Company, after deducting underwriting discounts and commissions and other offering expenses payable by the Company. Upon the closing of the Company’s IPO, the Company filed an amended and restated certificate of incorporation, which authorized the Company to issue 300,000,000 shares of common stock and 10,000,000 shares of preferred stock, which shares of preferred stock are currently undesignated. The Company had 25,261,832 common shares outstanding at December 31, 2020. The Company had 5,350,404 common shares authorized, of which 259,966 shares were issued and outstanding at December 31, 2019. Common stockholders are entitled to one vote for each share of common stock held at all meetings of stockholders and written actions in lieu of meetings. Common stockholders are entitled to receive dividends, if and when declared by the Board. No dividends have been declared or paid by the Company through December 31, 2020.

Equity-Based Compensation

Equity-Based Compensation	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Equity-Based Compensation	11. EQUITY-BASED COMPENSATION Employee equity plan In March 2020, the Company replaced the 2013 Option Program, or (“2013 Plan”), with its 2020 Stock Option and Grant Plan, or (“2020 Plan”). The 2020 Plan initially allowed the Company to award up to 1,740,325 options and the 304,142 outstanding options granted under the 2013 Plan were transferred to the 2020 Plan. Each vested option will entitle the option holder to purchase a single common share in the Company. Holders of stock options shall be entitled to exercise the vested portion of the stock option during the time period as determined by the Board, provided that a qualified exit, as defined in the 2020 Plan, has occurred. If a qualified exit, as defined in the 2020 Plan, occurs then all of the holders unvested options shall vest immediately. Options that are not exercised during the exercise period will automatically be forfeited. Stock options generally vest over a three-year or four-year period and expire ten years from the grant date. In October 2020, the Board approved the 2020 Equity Incentive Plan or (“2020 Equity Plan”). The 2020 Equity Plan allowed the Company to award up to 1,625,858 options and the 2,512,427 outstanding options granted under the 2020 Plan were transferred to the 2020 Equity Plan and no further options were available to be issued under the 2020 Plan. The 2020 Equity Plan will cumulatively increase by 5 percent of the number of shares of common stock issued and outstanding on January 1 st The following table sets forth the activity for the Company’s stock options during the periods presented: Number of Options Weighted- average exercise price per share Weighted- average remaining contractual term (in years) Aggregate intrinsic value Outstanding at December 31, 2018 304,142 $ 5.58 — — Granted — — — — Outstanding at December 31, 2019 304,142 5.58 — — Granted 2,235,285 4.67 — — Exercised (1,016 ) 1.95 — $ 5,842 Outstanding at December 31, 2020 2,538,411 $ 4.67 8.8 $ 20,009,769 Vested and expected to vest at December 31, 2020 2,234,269 $ 4.57 9.5 $ 17,845,220 Exercisable at December 31, 2020 695,373 $ 3.48 6.6 $ 6,282,748 The weighted-average grant date fair value of all stock options granted during the year ended December 31, 2020 was $3.35. No options were granted during the year ended December 31, 2019. The intrinsic value at December 31, 2020 is based on the closing price of the Company’s common stock on that date of $12.51 per share Equity-based compensation The Company recorded stock-based compensation expense of $1.0 million related to the issuance of stock options during the year ended December 31, 2020, which $0.6 million was recorded as general and administrative expense and $0.4 million was recorded as research and development expense. The fair value of stock options vested during the year ended December 31, 2020 was $0.3 million. At December 31, 2020, there was $6.5 million of unrecognized stock-based compensation expense relating to stock options granted pursuant to the 2020 Equity Plan, which will be recognized over the weighted-average remaining vesting period of 3.5 years. The fair values of the options granted were estimated based on the Black-Scholes model, using the following assumptions: 2020 Risk-free interest rate 0.4 % Expected term (in years) 5.8 Expected volatility 90.1 % Expected dividend yield 0 %

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	12. INCOME TAXES The Company had no income tax expense or benefit for the years ended December 31, 2020 and 2019. The Company has incurred net operating losses for all the periods presented. The Company has not reflected the benefit of any such net operating loss carryforwards in the accompanying financial statements. As of December 31, 2019, the domicile of the reporting entity has changed from Denmark to the United States resulting in a tax rate of 21% in 2020 and 2019. This is discussed further below. The components of net loss are as follows (in thousands): Year Ended December 31, 2020 2019 Domestic $ (7,544 ) $ (16,788 ) Foreign (27,293 ) (19,719 ) Total $ (34,837 ) $ (36,507 ) Reconciliation of Effective Tax Rate The effective tax rate for the years ended December 31, 2020 and 2019 is different from the statutory rate primarily due to the valuation allowance against deferred tax assets as a result of insufficient sources of income. The reconciliation of the statutory income tax rate to the Company’s effective income tax rate is as follows: Year Ended December 31, 2020 2019 Income tax benefit at the statutory rate 21.0 % 21.0 % State income taxes 2.9 0.7 Permanent differences 2.5 0.7 Research and development tax credits 2.3 (1.8 ) Foreign rate differential 0.8 0.6 Purchased in-process research and development — (9.7 ) Other — 0.2 Change in valuation allowance (29.5 ) (11.0 ) Total — % — % Deferred taxes Deferred income taxes reflect the net effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The principal components of the Company’s deferred tax assets consisted of the following (in thousands): December 31, Deferred tax assets: 2020 2019 Net operating loss carryforwards $ 18,471 $ 8,980 Research and development credits 2,828 2,019 Bonus compensation 322 156 Total deferred tax assets $ 21,621 $ 11,155 Valuation allowance (21,621 ) (11,155 ) Net deferred tax assets $ — $ — In assessing the realizability of deferred tax assets, management considers whether it is more-likely-than-not that some portion or all of the deferred tax assets will not be realized. The Company regularly assesses the likelihood that the deferred tax assets will be recovered from future taxable income. The Company considers projected future taxable income and ongoing tax planning strategies, then records a valuation allowance to reduce the carrying value of the net deferred taxes to an amount that is more-likely-than-not able to be realized. Based upon the Company’s assessment of all available evidence, including the previous three years of taxable income and loss after permanent items, estimates of future profitability, and the Company’s overall prospects of future business, the Company determined that it is more-likely-than-not that the Company will not be able to realize a portion of the deferred tax assets in the future. The Company will continue to assess the potential realization of deferred tax assets on an annual basis, or an interim basis if circumstances warrant. If the Company’s actual results and updated projections vary significantly from the projections used as a basis for this determination, the Company may need to change the valuation allowance against the gross deferred tax assets. On the basis of this evaluation, a full valuation allowance at December 31, 2020 and December 31, 2019 was recorded of $21.6 million and $11.2 million respectively to reduce the net deferred tax assets to their estimated realizable value. The change in valuation allowance was $10.4 million. The Company is subject to taxation in the United States, Denmark and Sweden. As of December 31, 2020, tax years 2016 and forward were generally open to examination by the Danish tax authorities and tax year 2019 and forward was open to examination by the United States tax authorities. The Company is not under examination by any taxing authorities. As of December 31, 2020, the Company had gross U.S. federal net operating losses, or NOLs, of $11.5 million and federal research and development credits, or R&D credits, of $1.2 million to offset tax liabilities. The federal NOLs and federal R&D credit carryforwards begin to expire in 2036 and 2033, respectively. Of the federal NOLs, $11.4 million have an infinite life. The Company also had gross state NOLs of $18.6 million and state R&D credits of $1.1 million which are available to offset state tax liabilities. The state NOLs begin to expire in 2036 and the state tax R&D credits have an indefinite life. The Company also had NOLs in Denmark of $67.3 million which have an indefinite life. Federal and state NOLs and R&D credit carryforwards are also subject to annual limitations in the event that cumulative changes in the ownership interests of significant stockholders exceed 50% over a three-year period, as defined under Sections 382 and 383 of the Internal Revenue Code of 1986. The Company has not completed an analysis to determine if the NOLs and R&D credits are limited due to a change in ownership. The Company recognizes accrued interest related to unrecognized tax benefits and penalties as income tax expense. The Company does not have any material unrecognized tax benefits which would affect the effective tax rate if recognized. The Company does not have any unrecognized tax benefits which would reverse within the next twelve months. The Company is eligible for the Danish enhanced research and development tax allowance, providing for an increase in the deductible value of the amount of certain R&D expenditures. The deduction for R&D expenditures is set at 101.5% for 2019, 130% for 2020 through 2021, 108% for 2022 through 2025 and 110% for 2026.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Net Loss Per Share	13. NET LOSS PER SHARE Basic and diluted net loss per share is calculated as follows (in thousands except share and per share amounts): Year Ended December 31, 2020 2019 Net loss $ (34,837 ) $ (36,507 ) Cumulative dividends on convertible preferred stock — (5,560 ) Net loss attributable to common stockholders $ (34,837 ) $ (42,067 ) Net loss per common share, basic and diluted $ (7.62 ) $ (161.82 ) Weighted-average number of shares used in computing net loss per common share, basic and diluted 4,572,702 259,966 The following outstanding potentially dilutive securities have been excluded from the calculation of diluted net loss per share, as their effect is anti-dilutive: Year Ended December 31, 2020 2019 Convertible preferred stock — 4,809,124 Stock options to purchase common stock 2,538,411 304,142

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	14. RELATED PARTY TRANACTIONS During the year ended December 31, 2020 and 2019, the Company had no material related party transactions.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	15. SUBSEQUENT EVENTS The Company has evaluated subsequent events through the date on which the consolidated financial statements were issued. The Company has concluded that no subsequent events have occurred that require disclosure to the consolidated financial statements.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of presentation	Basis of presentation The accompanying consolidated financial statements have been prepared in conformity with U.S. GAAP. Any reference in these notes to applicable guidance is meant to refer to U.S. GAAP, as found in the Accounting Standards Codification, or ASC, and Accounting Standards Update, or ASU, of the Financial Accounting Standards Board, or FASB.
Principles of consolidation	Principles of consolidation The Company’s consolidated financial statements for 2020 and 2019 include the accounts of Galecto, Inc. and its subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Use of estimates	Use of estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect certain reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of expenses during the reporting periods. Significant items subject to such estimates and assumptions include contract research accruals, stock-based compensation expense, the fair value of the Company’s common stock and valuation of the Company’s deferred tax assets. The Company bases its estimates on historical experience and various other assumptions that management believes to be reasonable under the circumstances. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates.
Currency and currency translation	Currency and currency translation The consolidated financial statements are presented in U.S. dollars, the Company’s reporting currency. Galecto, Inc., Galecto Securities Corporation and PharmAkea’s functional currency is the U.S. dollar. The functional currency of the Company’s subsidiary Galecto Biotech AB, and its subsidiary Galecto Biotech ApS, is the Euro. Adjustments that arise from exchange rate changes on transactions of each group entity denominated in a currency other than the functional currency are included in other income and expense in the consolidated statements of operations. Assets and liabilities of Galecto Biotech AB and Galecto Biotech ApS recorded in their Euro functional currency are translated into the U.S. dollar reporting currency of the Company at the exchange rate on the balance sheet date. Revenue and expenses of Galecto Biotech AB and Galecto Biotech ApS recorded in their Euro functional currency are translated into the U.S. dollar reporting currency of the Company at the average exchange rate prevailing during the year. Resulting translation adjustments are recorded to other comprehensive income (loss), or OCI.
Cash and cash equivalents	Cash and cash equivalents The Company considers all highly liquid investments with original maturities at the date of purchase of three months or less to be cash equivalents. Cash and cash equivalents are stated at fair value and may include money market funds, U.S. Treasury and U.S. government-sponsored agency securities, corporate debt, commercial paper and certificates of deposit. The Company had money market funds of $142.9 million as of December 31, 2020, which are included in cash and cash equivalents and reported at fair value (Note 3). The Company had no cash equivalents as of December 31, 2019.
Restricted cash	Restricted cash The Company is required to maintain cash collateral on deposit in a segregated money market bank account, as a condition of its security deposit with one of its banks for the use of corporate credit cards. As of December 31, 2020 and 2019, the Company presented restricted cash in the accompanying consolidated balance sheets of $254,000 and $231,000, respectively.
Concentrations of credit risk and off-balance sheet risk	Concentrations of credit risk and off-balance sheet risk The Company maintains its cash in bank deposit and checking accounts that at times exceed insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to any significant credit risk.
Fair value of financial instruments	Fair value of financial instruments Fair value is defined as the price the Company would receive to sell an investment in a timely transaction or pay to transfer a liability in a timely transaction with an independent buyer in the principal market, or in the absence of a principal market, the most advantageous market for the investment or liability. A framework is used for measuring fair value utilizing a three-tier hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). The three levels of the fair value hierarchy are as follows: Level 1 —Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; Level 2 —Quoted prices in markets that are not considered to be active or financial instrument valuations for which all significant inputs are observable, either directly or indirectly; and Level 3 —Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable. Financial instruments are categorized in their entirety based on the lowest level of input that is significant to the fair value measurement. The assessment of the significance of a particular input to the fair value measurement requires judgment and considers factors specific to the investment. To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by us in determining fair value is greatest for instruments categorized in Level 3. The Company monitors the availability of inputs that are significant to the measurement of fair value to assess the appropriate categorization of financial instruments within the fair value hierarchy. Changes in economic conditions or model-based valuation techniques may require the transfer of financial instruments from one fair value level to another. In such instances, our policy is to recognize significant transfers between levels at the end of the reporting period. The significance of transfers between levels is evaluated based upon the nature of the financial instrument and size of the transfer relative to total net assets available for benefits.
Research and development expenses	Research and development expenses Research and development costs are expensed as incurred. The Company’s research and development expenses consist primarily of costs incurred for the development of its product candidates and include expenses incurred under agreements with contract manufacturing organizations, or CMOs, contract research organizations, or CROs, investigative sites and consultants to conduct clinical trials and preclinical and non-clinical studies, costs to acquire, develop and manufacture supplies for clinical trials and other studies, salaries and related costs, including stock-based compensation, depreciation and other allocated facility-related and overhead expenses and licensing fees and milestone payments incurred under product license agreements where no alternative future use exists. From time to time, Galecto obtains grants from public and private funds for its research and development projects. The grant income for a given period is recognized as a cost reimbursement and is typically based on the time and the costs that Galecto has spent on the specific project during that period. During the year ended 2019, the Company had two active cost reimbursement grants with Tufts University and with the Innovation Fund of Denmark. The grants provided reimbursement of direct research and development costs. For the year ended December 31, 2019, research and development expenses in the consolidated statements of operations include $388,000 and of grant income cost reimbursement. There was no grant income cost reimbursement for the year ended December 31, 2020. The Company has met the requirements to receive a tax credit in Denmark for losses resulting from research and development costs of up to $4.1 million for the years ended December 31, 2020 and 2019. The tax credit is reported as a reduction to research and development expense in the consolidated statements of operations. For the years ended December 31, 2020 and 2019, research and development expenses include refundable tax credits of $809,000 and $824,000 respectively.
Accrued research and development costs	Accrued research and development costs Substantial portions of the Company’s preclinical and clinical trials are performed by third-party laboratories, medical centers, CROs and other vendors, or collectively, CROs. These CROs generally bill monthly for services performed, or bill based upon milestone achievement. For preclinical studies, the Company accrues expenses based upon estimated percentage of work completed and the contract milestones remaining. For clinical studies, expenses are accrued based upon the number of patients enrolled and the duration of the study. The Company monitors patient enrollment, the progress of clinical studies and related activities to the extent possible through internal reviews of data reported to the Company by the CROs, correspondence with the CROs and clinical site visits. The Company’s estimates depend on the timeliness and accuracy of the data provided by the CROs regarding the status of each program and total program spending. The Company periodically evaluates the estimates to determine if adjustments are necessary or appropriate based on information it receives.
Acquired in-process research and development expenses	Acquired in-process research and development expenses The Company includes costs to acquire or in-license product candidates in acquired in-process research and development expenses. The Company has acquired the right to develop and commercialize its product candidate PAT-1251, which the Company now refers to as GB2064. These costs are immediately expensed provided that the payments do not also represent processes or activities that would constitute a business as defined under U.S. GAAP or provided that the product candidate has not achieved regulatory approval for marketing and absent obtaining such approval, has no alternative future use.
Leases	Leases In February 2016, the FASB established Topic 842, Leases Leases Land Easement Practical Expedient for Transition to Topic 842 Codification Improvements to Topic 842, Leases Targeted Improvements The Company adopted ASU 842 on January 1, 2019 using the modified retrospective method, in which case the cumulative effect of applying the standard would be recognized at the date of initial application. The Company has completed a qualitative and quantitative assessment of its lease portfolio, in which the standard had a material impact on the consolidated balance sheets but did not have an impact on the consolidated statements of operations and comprehensive loss. Upon adoption, the Company recognized lease liabilities of $379,000 based on the present value of the remaining minimum rental payments under current leasing standards for the Company’s existing operating leases. The corresponding ROU assets of $379,000 recognized upon adoption are net of deferred rent. ASU 842 provides a number of optional practical expedients in transition. The Company elected the package of practical expedients that permit lessees not to reassess under ASU 842 prior conclusions about lease identification, lease classification and initial direct costs. The Company did not elect the use-of-hindsight or the practical expedient pertaining to land easements; the latter not being applicable to the Company. The new standard also provides practical expedients for an entity’s ongoing accounting. The Company elected the short-term lease recognition exemption for all leases that qualify. This means, for those leases that qualify, ROU assets or lease liabilities will not be recognized, and this includes not recognizing ROU assets or lease liabilities for existing short-term leases of those assets in transition. The Company also elected the practical expedient to not separate lease and non-lease components for office leases. At inception of a contract, the Company determines whether an arrangement is or contains a lease. For all leases, the Company determines the classification as either operating leases or finance leases. Operating leases are included in Operating lease right-of-use assets and Operating lease liabilities in the Company’s consolidated balance sheets. Lease recognition occurs at the commencement date and lease liability amounts are based on the present value of lease payments over the lease term. The lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. If a lease does not provide information to determine an implicit interest rate, the Company uses the Company’s incremental borrowing rate in determining the present value of lease payments. ROU assets represent the right to use an underlying asset for the lease term, and lease liabilities represent the obligation to make lease payments under the lease. ROU assets also include any lease payments made prior to the commencement date and exclude lease incentives received. Operating lease expense is recognized on a straight-line basis over the lease term. The depreciable life of assets and leasehold improvements are limited by the expected lease term, unless there is a transfer of title or purchase option reasonably certain of exercise. Lease agreements with both lease and non-lease components, are generally accounted for together as a single lease component. Refer to Note 6 for further details.
Convertible preferred stock	Convertible preferred stock The Company classifies convertible preferred stock outside of stockholders’ deficit on its consolidated balance sheet as the requirements of triggering a deemed liquidation event are not within the Company’s control. In the event of a deemed liquidation event, the proceeds from the event are distributed in accordance with liquidation preferences (see Note 9). The Company records the issuance of convertible preferred stock at the issuance price less related issuance costs and less any discount arising on allocation of proceeds to one or more derivative features. Immediately prior to consummation of the Company’s IPO, all outstanding shares of the Company’s convertible preferred stock were converted into shares of common stock.
Equity-based compensation	Equity-based compensation The Company accounts for stock options granted in accordance with ASC 718, Compensation-Stock Compensation All share-based awards granted are measured based on the fair value on the date of the grant and compensation expense is recognized with respect to those awards over the requisite service period, which is generally the vesting period of the respective award. The Company reverses any previously recognized compensation cost associated with forfeited awards in the period the forfeiture occurs. Equity-based compensation expense is classified in the Company’s consolidated statement of operations and comprehensive loss in the same manner in which the award recipients’ payroll costs are classified or in which the award recipients’ service payments are classified. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes model. The following summarizes the inputs used: Expected volatility —The Company estimates its expected stock volatility based on the historical volatility of a publicly traded set of peer companies because we lack company-specific historical and implied volatility information due in part to the limited time in which we have operated as a publicly traded company. We expect to continue to do so until such time as we have adequate historical data regarding the volatility of our traded stock price. Expected term —The expected term of the Company’s stock options has been determined based on the expected time to liquidity. The Company uses the simplified method prescribed by the SEC’s Staff Accounting Bulletin No. 107, Share-Based Payment , to calculate the expected term of options granted because we lack company-specific historical and implied expected term information due in part to the limited time in which we have operated as a publicly traded company. Risk-free interest rate —The risk-free interest rate is based on the implied yield on a U.S. Treasury security at a constant maturity with a remaining term equal to the expected term of the option granted. Dividends —Expected dividend yield is zero because the Company does not pay cash dividends on common shares and does not expect to pay any cash dividends in the foreseeable future. Prior to the IPO, the Company’s board of directors, with input from management, determined the estimated fair value of the common shares as of the date of each incentive share grant considering the Company’s then-most recently available third-party valuation of common shares. Valuations are updated when facts and circumstances indicate that the most recent valuation is no longer valid, such as changes in the stage of development efforts, various exit strategies and their timing, and other scientific developments that could be related to the Company’s valuation, or, at a minimum, annually. Third-party valuations were performed in accordance with the guidance outlined in the American Institute of Certified Public Accountants’ Accounting and Valuation Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation
Income taxes	Income taxes Deferred income tax assets and liabilities arise from temporary differences associated with differences between the financial statements and tax basis of assets and liabilities, as measured by the enacted tax rates, which are expected to be in effect when these differences reverse. Valuation allowances are established when necessary to reduce deferred tax assets to the amount expected to be realized. The Company has generated net losses since inception and accordingly has not recorded a provision for income taxes. The Company follows the provisions of ASC 740-10, Uncertainty in Income Taxes, The Company has identified the United States, Denmark and Sweden as its major tax jurisdictions. Refer to Note 12 for further details.
Net loss per share	Net loss per share Basic net loss per share is computed by dividing the net loss by the weighted-average number of shares of common stock outstanding for the period. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of shares of common stock and dilutive common stock equivalents outstanding for the period, determined using the treasury-stock method and the as if-converted method, for convertible securities, if inclusion of these instruments is dilutive. For the year ended December 31, 2020 and 2019, both methods are equivalent. Basic and diluted net loss per share are described further in Note 13.
Segments	Segments Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the chief operating decision maker, or CODM, in deciding how to allocate resources to an individual segment and in assessing performance. The Company’s CODM is its chief executive officer. The Company has determined it operates in one segment.
Other comprehensive income (loss)	Other comprehensive income (loss) OCI is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. The Company’s OCI includes currency translation.
Emerging growth company status	Emerging growth company status The Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012, or JOBS Act. Under the JOBS Act, emerging growth companies can delay adopting new or revised accounting standards issued subsequent to the enactment of the JOBS Act, until such time as those standards apply to private companies. The Company may elect to use this extended transition period for complying with new or revised accounting standards that have different effective dates for public and private companies until the earlier of the date that it (i) is no longer an emerging growth company or (ii) affirmatively and irrevocably opts out of the extended transition period provided in the JOBS Act. As a result, these financial statements may not be comparable to companies that comply with the new or revised accounting pronouncements as of public company effective dates.
Recently adopted accounting standards and Recently issued accounting standards	Recently adopted accounting standards In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480) and Derivatives and Hedging (Topic 815): I. Accounting for Certain Financial Instruments with Down Round Features; and II. Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception Distinguishing Liabilities from Equity Prior to January 1, 2019, the Company accounted for leases under ASC 840, Accounting for Leases Leases In June 2018, the FASB issued ASU No. 2018-07, Compensation – Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting Recently issued accounting standards In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments Codification Improvements to Topic 326, Financial Instruments-Credit Losses, Topic 815, Derivatives and Hedging and Topic 825, Financial Instruments During August 2018, the FASB issued ASU No. 2018-13, D isclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement Fair Value Measurement. The amendments are based on the concepts in the FASB Concepts Statement, Conceptual Framework for Financial Reporting—Chapter 8: Notes to Financial Statements In December 2019, the FASB issued ASU No. 2019-12, Simplifying the Accounting for Income Taxes

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Summary of Assets Measured at Fair Value	A summary of the assets that are measured at fair value as of December 31, 2020 is as follows (in thousands): Fair Value Measurement at December 31, 2020 Assets: Carrying Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Money market funds ( 1) $ 142,904 $ 142,904 $ — $ — Total $ 142,904 $ 142,904 $ — $ — (1) Money market funds with maturities of 90 days or less at the date of purchase are included within cash and cash equivalents in the accompanying consolidated balance sheets and are recognized at fair value.
Schedule of Reconciliation of Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs	The following table provides a reconciliation of the Company’s liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) (in thousands): Preferred Stock Tranche Obligations Balance, December 31, 2018 $ 1,744 Fair value adjustments (1,913 ) Settlement on commitment to purchase Series C preferred stock 169 Balance, December 31, 2019 $ —

Purchase of PharmAkea, Inc. (Ta

Purchase of PharmAkea, Inc. (Tables)	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Schedule of Purchase Price	The following summarizes the purchase price of the Purchase (in thousands, except share and per share amounts): Value of the shares of Series C preferred stock issued to former PharmAkea stockholders $ 15,625 Cash consideration to non-accredited former PharmAkea stockholders 216 Payments made and Company options issued to former PharmAkea executives pursuant to the terms of the Purchase 583 Transaction costs 978 Purchase price $ 17,402
Schedule of Total Purchase Price Allocated to Assets Acquired and Liabilities Assumed	The total purchase price has been allocated to the assets acquired and liabilities assumed as of December 31, 2019 as follows (in thousands): Purchased in-process research and development—GB2064 $ 16,788 Cash acquired 653 Trade liabilities assumed (39 ) Purchase price $ 17,402

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	12 Months Ended
	Dec. 31, 2020
Prepaid Expense And Other Assets Current [Abstract]
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consist of the following (in thousands): December 31, 2020 2019 Research and development tax credit receivable $ 1,808 $ 827 Prepaid insurance costs 1,642 — Contract research and development costs 1,620 3,344 Value-added tax refund receivable 401 253 Grant reimbursement receivable — 379 Other 242 314 Total prepaid expenses and other current assets $ 5,713 $ 5,117

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Quantitative Information Regarding Leases	Quantitative information regarding the Company’s leases for the years ended December 31, 2020 and 2019 is as follows (in thousands): Year Ended December 31, Lease Cost: 2020 2019 Operating lease cost $ 213 $ 129 Other Information: Operating cash flows paid for amounts included in the measurement of lease liabilities $ 213 $ 129 Operating lease liabilities arising from obtaining right-of-use assets $ 713 $ 391 Weighted average remaining lease term (years) 2.8 4.2 Weighted average discount rate 8.0 % 8.0 %
Summary of Future Lease Payments under Noncancelable Leases	Future lease payments under noncancelable leases are as follows at December 31, 2020 (in thousands): Future Lease Payments Operating Leases 2021 $ 434 2022 325 2023 145 2024 121 2025 — Total lease payments 1,025 Less: imputed interest (110 ) Total lease liabilities $ 915

Accrued Expenses And Other Cu_2

Accrued Expenses And Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2020
Payables And Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following (in thousands): December 31, 2020 2019 Employee compensation costs $ 1,031 $ 113 Contract research and development costs 967 3,493 Lease liabilities 374 87 Costs related to the Purchase of PharmAkea — 838 Other liabilities 343 67 Total accrued expenses and other current liabilities $ 2,715 $ 4,598

Equity-Based Compensation (Tabl

Equity-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock Options Activity	The following table sets forth the activity for the Company’s stock options during the periods presented: Number of Options Weighted- average exercise price per share Weighted- average remaining contractual term (in years) Aggregate intrinsic value Outstanding at December 31, 2018 304,142 $ 5.58 — — Granted — — — — Outstanding at December 31, 2019 304,142 5.58 — — Granted 2,235,285 4.67 — — Exercised (1,016 ) 1.95 — $ 5,842 Outstanding at December 31, 2020 2,538,411 $ 4.67 8.8 $ 20,009,769 Vested and expected to vest at December 31, 2020 2,234,269 $ 4.57 9.5 $ 17,845,220 Exercisable at December 31, 2020 695,373 $ 3.48 6.6 $ 6,282,748
Summary of Fair Value Assumptions of Options Granted Estimated Based on Black-Scholes Model	The fair values of the options granted were estimated based on the Black-Scholes model, using the following assumptions: 2020 Risk-free interest rate 0.4 % Expected term (in years) 5.8 Expected volatility 90.1 % Expected dividend yield 0 %

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Summary of Components of Net Loss	The components of net loss are as follows (in thousands): Year Ended December 31, 2020 2019 Domestic $ (7,544 ) $ (16,788 ) Foreign (27,293 ) (19,719 ) Total $ (34,837 ) $ (36,507 )
Schedule of Reconciliation of Statutory Income Tax Rate to Effective Income Tax Rate	. The reconciliation of the statutory income tax rate to the Company’s effective income tax rate is as follows: Year Ended December 31, 2020 2019 Income tax benefit at the statutory rate 21.0 % 21.0 % State income taxes 2.9 0.7 Permanent differences 2.5 0.7 Research and development tax credits 2.3 (1.8 ) Foreign rate differential 0.8 0.6 Purchased in-process research and development — (9.7 ) Other — 0.2 Change in valuation allowance (29.5 ) (11.0 ) Total — % — %
Schedule of Components of Company's Deferred Tax Assets	The principal components of the Company’s deferred tax assets consisted of the following (in thousands): December 31, Deferred tax assets: 2020 2019 Net operating loss carryforwards $ 18,471 $ 8,980 Research and development credits 2,828 2,019 Bonus compensation 322 156 Total deferred tax assets $ 21,621 $ 11,155 Valuation allowance (21,621 ) (11,155 ) Net deferred tax assets $ — $ —

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Net Loss Per Share	Basic and diluted net loss per share is calculated as follows (in thousands except share and per share amounts): Year Ended December 31, 2020 2019 Net loss $ (34,837 ) $ (36,507 ) Cumulative dividends on convertible preferred stock — (5,560 ) Net loss attributable to common stockholders $ (34,837 ) $ (42,067 ) Net loss per common share, basic and diluted $ (7.62 ) $ (161.82 ) Weighted-average number of shares used in computing net loss per common share, basic and diluted 4,572,702 259,966
Schedule of Antidilutive Securities Excluded from Calculation of Diluted Net Loss Per Share	The following outstanding potentially dilutive securities have been excluded from the calculation of diluted net loss per share, as their effect is anti-dilutive: Year Ended December 31, 2020 2019 Convertible preferred stock — 4,809,124 Stock options to purchase common stock 2,538,411 304,142

Description of Business, Orga_2

Description of Business, Organization and Liquidity - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Description Of Business Organization And Liquidity [Line Items]
Entity incorporation date	Oct. 31, 2019
Conversion of stock description	On December 31, 2019, as part of an integrated transaction, Galecto, Inc., Galecto Biotech AB, a Swedish operating company, and PharmAkea, Inc., or PharmAkea, consummated a purchase agreement and plan of merger by and among Galecto, Inc., Galecto Biotech AB and PharmAkea, or the Purchase, whereby Galecto, Inc. (i) acquired the shareholdings of Galecto Biotech AB via a one-for-one exchange of equity between Galecto, Inc. and the shareholders of Galecto Biotech AB in a common control reorganization, and (ii) acquired PharmAkea in principally an all-stock transaction.
Accumulated deficit	$ 104,360	$ 69,523
Net loss	(34,837)	(36,507)
Cash and cash equivalents	163,582	11,294
Current assets	169,295	56,080
Current liabilities	5,566	7,927
Clinical Development and Corporate General and Administrative Activities
Description Of Business Organization And Liquidity [Line Items]
Net loss	$ (38,200)	$ (19,300)

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2020USD ($)Segment	Dec. 31, 2019USD ($)	Jan. 01, 2019USD ($)
Summary Of Significant Accounting Policies [Line Items]
Original maturities at the date of purchase of liquid investments	three months or less
Money market funds	$ 142,900,000
Cash equivalents		$ 0
Restricted cash	254,000	231,000
Operating lease, liability	915,000
Operating lease right-of-use asset	885,000	298,000
Expected dividend yield	$ 0
Number of operating segments | Segment	1
ASU 842
Summary Of Significant Accounting Policies [Line Items]
Operating lease, liability			$ 379,000
Operating lease right-of-use asset			$ 379,000
Research and Development
Summary Of Significant Accounting Policies [Line Items]
Refundable tax credit	$ 4,100,000	4,100,000
Tax credit refund receivable	809,000	824,000
Research and Development Expense
Summary Of Significant Accounting Policies [Line Items]
Grant income cost reimbursement	$ 0	$ 388,000

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets measured at fair value	$ 142,904,000
Preferred Stock Tranche Obligation | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Preferred stock tranche obligation	0
Nonoperating gain		$ 1,900,000
Recurring Basis
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets measured at fair value		0
Financial liabilities measured at fair value		0
Fair value, assets, level 1 to level 2 transfers	0	0
Fair value, assets, level 2 to level 1 transfers	0	0
Fair value, liabilities, level 1 to level 2 transfers	0	0
Fair value, liabilities, level 2 to level 1 transfers	0	0
Fair value, measurement asset transfers into level 3	0	0
Fair value, measurement asset transfers out of level 3	0	0
Fair value, measurement liability, transfers into level 3	0	0
Fair value, measurement liability, transfers out of level 3	$ 0	$ 0
Recurring Basis | Preferred Stock Tranche Obligation | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Preferred stock tranche obligation			$ 1,700,000

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Assets Measured at Fair Value (Details) $ in Thousands	Dec. 31, 2020USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets fair value	$ 142,904
Level 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets fair value	142,904
Money Market Funds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets fair value	142,904
Money Market Funds | Level 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets fair value	$ 142,904

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Reconciliation of Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Details) - Level 3 - Preferred Stock Tranche Obligation $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 1,744
Fair value adjustments	(1,913)
Settlement on commitment to purchase Series C preferred stock	$ 169

Purchase of PharmAkea, Inc. - A

Purchase of PharmAkea, Inc. - Additional Information (Details)	12 Months Ended
	Dec. 31, 2020shares	Dec. 31, 2019Facilityshares
Business Acquisition [Line Items]
Preferred stock, issued	0
PharmAkea, Inc. | MPEEM | GB2064 | Myelofibrosis
Business Acquisition [Line Items]
Weighted average cost of capital	45.00%
PharmAkea, Inc. | Series C Convertible Preferred Stock
Business Acquisition [Line Items]
Preferred stock, issued		610,098
Business acquisition, percentage of voting interests acquired		13.00%
Number of facilities, employees, customers or assets at the time of acquisition | Facility		0
Business acquisition, description	The Company was determined to be the accounting acquirer, and the Purchase of PharmAkea has been accounted for as an asset acquisition pursuant to Topic 805, Business Combinations, as the principal asset acquired was PharmAkea’s Phase 1 clinical development program of an orally delivered inhibitor of LOXL2 for the treatment of Myelofibrosis and other fibrotic indications, which the Company refers to as GB2064. At the time of the Purchase, PharmAkea had no facilities, employees, customers or assets other than the GB2064 program.

Purchase of PharmAkea, Inc. - S

Purchase of PharmAkea, Inc. - Summary of Purchase Price (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Value of the shares of Series C preferred stock issued to former PharmAkea stockholders	$ 86,360
PharmAkea, Inc.
Business Acquisition [Line Items]
Cash consideration to non-accredited former PharmAkea stockholders		$ 216
Payments made and Company options issued to former PharmAkea executives pursuant to the terms of the Purchase		583
Transaction costs		978
Purchase price		17,402
PharmAkea, Inc. | Series C Preferred Stock
Business Acquisition [Line Items]
Value of the shares of Series C preferred stock issued to former PharmAkea stockholders		$ 15,625

Purchase of PharmAkea, Inc. -_2

Purchase of PharmAkea, Inc. - Summary of Purchase Price Allocated to Assets Acquired and Liabilities assumed (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Business Acquisition [Line Items]
Purchased in-process research and development—GB2064	$ 16,788
PharmAkea, Inc.
Business Acquisition [Line Items]
Purchased in-process research and development—GB2064	16,788
Cash acquired	653
Trade liabilities assumed	(39)
Purchase price	$ 17,402

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Prepaid Expense And Other Assets Current [Abstract]
Research and development tax credit receivable	$ 1,808	$ 827
Prepaid insurance costs	1,642
Contract research and development costs	1,620	3,344
Value-added tax refund receivable	401	253
Grant reimbursement receivable		379
Other	242	314
Total prepaid expenses and other current assets	$ 5,713	$ 5,117

Leases - Additional Information

Leases - Additional Information (Details)	1 Months Ended				12 Months Ended
	Jan. 31, 2021USD ($)	Aug. 31, 2020	Jul. 31, 2020	Jun. 30, 2020ft²	Dec. 31, 2020USD ($)Facility	Dec. 31, 2019USD ($)
Leases [Line Items]
Number of office and laboratory space | Facility					3
Rent expense					$ 250,000	$ 222,000
Future lease payments					$ 1,025,000
Denmark
Leases [Line Items]
Operating lease, expiration date					Oct. 31, 2021
Office space under operating lease | ft²				1,300
Description of lease, option to extend					The renewal option will expire in October 2024 and additional lease payments of $288,000 are included in the future lease payments above.
Lease renewal option expiration date					Oct. 31, 2024
Future lease payments					$ 288,000
United Kingdom
Leases [Line Items]
Operating lease, expiration date		Aug. 31, 2020			Aug. 31, 2022
Operating lease description					In January 2021, the Company entered into an operating lease agreement in Stevenage, United Kingdom, for laboratory space. The lease agreement has a three-year term, which expires in January 2024 and has a renewal option.
United Kingdom | Subsequent Event
Leases [Line Items]
Operating lease, expiration date	Jan. 31, 2024
Future lease payments	$ 179,000
Operating lease, option to extend	true
Operating lease, term of contract	3 years
Sweden
Leases [Line Items]
Operating lease, expiration date					Sep. 30, 2022
Canada
Leases [Line Items]
Operating lease, expiration date			Jul. 31, 2020

Leases - Quantitative Informati

Leases - Quantitative Information Regarding Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lease Cost:
Operating lease cost	$ 213	$ 129
Operating cash flows paid for amounts included in the measurement of lease liabilities	213	129
Operating lease liabilities arising from obtaining right-of-use assets	$ 713	$ 391
Weighted average remaining lease term (years)	2 years 9 months 18 days	4 years 2 months 12 days
Weighted average discount rate	8.00%	8.00%

Leases - Summary of Future Leas

Leases - Summary of Future Lease Payments under Noncancelable Leases (Details) $ in Thousands	Dec. 31, 2020USD ($)
Future Lease Payments
2021	$ 434
2022	325
2023	145
2024	121
Total lease payments	1,025
Less: imputed interest	(110)
Operating lease, liability	$ 915

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Employee compensation costs	$ 1,031	$ 113
Contract research and development costs	967	3,493
Lease liabilities	$ 374	$ 87
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	glto:LeaseLiabilitiesMember	glto:LeaseLiabilitiesMember
Other liabilities	$ 343	$ 67
Total accrued expenses and other current liabilities	$ 2,715	4,598
PharmAkea, Inc.
Costs related to the Purchase of PharmAkea		$ 838

Convertible Preferred Stock - A

Convertible Preferred Stock - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 31, 2020
Class of Stock [Line Items]
Receivable on issuance of series C convertible preferred stock or Series C preferred stock			$ 39,700		$ 39,700
Preferred stock, issued (in shares)		0
Series C-2 Preferred Shares
Class of Stock [Line Items]
Redeemable convertible preferred stock issued				1,284,795
Net proceeds from issuance of redeemable convertible preferred stock				$ 34,500
Series C-4 Preferred Shares
Class of Stock [Line Items]
Redeemable convertible preferred stock issued			1,199,143
Series C-5 Preferred Shares
Class of Stock [Line Items]
Redeemable convertible preferred stock issued			342,612
Net proceeds from issuance of redeemable convertible preferred stock			$ 39,700
Series C-3 Preferred Shares
Class of Stock [Line Items]
Redeemable convertible preferred stock issued			198,770
Series D Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, issued (in shares)	2,368,118
Proceeds from issuance of preferred stock	$ 64,200
Proceeds from issuance or sale of equity	61,400
Payments of stock issuance costs	$ 2,800	$ 2,840
Conversion of convertible preferred stock into common stock		18,658,643
Series B Convertible Preferred Stock
Class of Stock [Line Items]
Conversion of convertible preferred stock into common stock		18,658,643
Series C Convertible Preferred Stock
Class of Stock [Line Items]
Receivable on issuance of series C convertible preferred stock or Series C preferred stock			$ 39,669
Conversion of convertible preferred stock into common stock		18,658,643

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		12 Months Ended
	Nov. 30, 2020	Oct. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Subsidiary Sale Of Stock [Line Items]
Common stock, authorized		300,000,000	300,000,000	5,350,404
Preferred stock, authorized		10,000,000	10,000,000	0
Common stock, outstanding			25,261,832	259,966
Common stock, issued			25,261,832	259,966
Common stock, voting rights			one vote
Common stock, dividends per share declared			$ 0
Common stock, dividends per share paid			$ 0
Initial Public Offering
Subsidiary Sale Of Stock [Line Items]
Issuance of common stock in connection with initial public offering, net of issuance costs (in shares)		6,342,207
Stock issued during period, price per shares		$ 15
Shares granted to underwriters	675,540
Stock issued during period, net proceeds		$ 86.3

Equity-Based Compensation - Add

Equity-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		12 Months Ended
	Oct. 31, 2020	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, granted			2,235,285
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, granted				0
Weighted-average grant date fair value of stock options granted			$ 3.35
Intrinsic value per share of stock options			$ 12.51
Stock-based compensation expense			$ 1
Fair value of stock options vested			0.3
Stock Options | General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			0.6
Stock Options | Research and Development Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense			$ 0.4
2020 Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, granted		304,142
Stock options, expiration period		10 years
2020 Equity Incentive Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, granted	2,512,427
Percentage increase of number of shares of common stock issued and outstanding	5.00%
Stock options available for future grant			1,598,858
Unrecognized compensation expense			$ 6.5
Unrecognized compensation expense that is expected to be recognized over a weighted-average period			3 years 6 months
Maximum | 2020 Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock options allowed to award		1,740,325
Stock options, vesting period		4 years
Maximum | 2020 Equity Incentive Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock options allowed to award	1,625,858
Minimum | 2020 Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting period		3 years

Equity-Based Compensation - Sum

Equity-Based Compensation - Summary of Stock Options Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options, Outstanding	304,142	304,142
Number of Options, Granted	2,235,285
Number of Options, Exercised	(1,016)
Number of Options, Outstanding	2,538,411	304,142
Number of Options, Vested and expected to vest	2,234,269
Number of Options, Exercisable	695,373
Weighted average exercise price per share, Outstanding	$ 5.58	$ 5.58
Weighted average exercise price per share, Granted	4.67
Weighted average exercise price per share, Exercised	1.95
Weighted average exercise price per share, Outstanding	4.67	$ 5.58
Weighted average exercise price per share, Vested and expected to vest	4.57
Weighted average exercise price per share, Exercisable	$ 3.48
Weighted average remaining contractual term (in years), Outstanding	8 years 9 months 18 days	0 years
Weighted average remaining contractual term (in years), Vested and expected to vest	9 years 6 months
Weighted average remaining contractual term (in years), Exercisable	6 years 7 months 6 days
Aggregate intrinsic value, Exercised	$ 5,842
Aggregate intrinsic value, Outstanding	20,009,769
Aggregate intrinsic value, Vested and expected to vest	17,845,220
Aggregate intrinsic value, Exercisable	$ 6,282,748

Equity-Based Compensation - S_2

Equity-Based Compensation - Summary of Fair Value Assumptions of Options Granted Estimated Based on Black-Scholes Model (Details)	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Risk-free interest rate	0.40%
Expected term (in years)	5 years 9 months 18 days
Expected volatility	90.10%
Expected dividend yield	0.00%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Income tax expense or benefit	$ 0	$ 0
Tax rate	21.00%	21.00%
Valuation allowance	$ 21,621,000	$ 11,155,000
Change in valuation allowance	$ 10,400,000
Operating loss carryforwards, Limitations on Use	The Company also had NOLs in Denmark of $67.3 million which have an indefinite life. Federal and state NOLs and R&D credit carryforwards are also subject to annual limitations in the event that cumulative changes in the ownership interests of significant stockholders exceed 50% over a three-year period, as defined under Sections 382 and 383 of the Internal Revenue Code of 1986.
Research and Development
Operating Loss Carryforwards [Line Items]
Tax allowance		101.50%
2020 through 2021 | Research and Development
Operating Loss Carryforwards [Line Items]
Tax allowance	130.00%
2022 through 2025 | Research and Development
Operating Loss Carryforwards [Line Items]
Tax allowance	108.00%
2026 | Research and Development
Operating Loss Carryforwards [Line Items]
Tax allowance	110.00%
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 11,500,000
Research and Development tax credits	1,200,000
Net operating loss carryforwards with infinite life	11,400,000
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	18,600,000
Research and Development tax credits	1,100,000
Denmark
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 67,300,000

Income Taxes - Summary of Compo

Income Taxes - Summary of Components of Net Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Domestic	$ (7,544)	$ (16,788)
Foreign	(27,293)	(19,719)
Total	$ (34,837)	$ (36,507)

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Statutory Income Tax Rate to Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Tax rate	21.00%	21.00%
State income taxes	2.90%	0.70%
Permanent differences	2.50%	0.70%
Research and development tax credits	2.30%	(1.80%)
Foreign rate differential	0.80%	0.60%
Purchased in-process research and development		(9.70%)
Other		0.20%
Change in valuation allowance	(29.50%)	(11.00%)

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Company's Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Net operating loss carryforwards	$ 18,471	$ 8,980
Research and development credits	2,828	2,019
Bonus compensation	322	156
Total deferred tax assets	21,621	11,155
Valuation allowance	$ (21,621)	$ (11,155)

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Net loss	$ (34,837)	$ (36,507)
Cumulative dividends on convertible preferred stock		(5,560)
Net loss attributable to common stockholders	$ (34,837)	$ (42,067)
Net loss per common share, basic and diluted	$ (7.62)	$ (161.82)
Weighted-average number of shares used in computing net loss per common share, basic and diluted	4,572,702	259,966

Net Loss Per Share - Schedule_2

Net Loss Per Share - Schedule of Antidilutive Securities Excluded from Calculation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share		4,809,124
Stock Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	2,538,411	304,142

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Related Party Transactions [Abstract]
Related party transactions	$ 0	$ 0