Galecto (GLTO) 10-Q 4 May 21 2021 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2021	Apr. 29, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Document Quarterly 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

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 74,253	$ 163,582
Marketable securities	36,081
Prepaid expenses and other current assets	6,568	5,713
Total current assets	116,902	169,295
Marketable securities, long-term	38,576
Other assets, noncurrent	1,116	1,162
Operating lease right-of-use asset	933	885
Property and equipment, net	63
Tax credit receivable, noncurrent	868
Restricted cash	197	254
Total assets	158,655	171,596
Current liabilities
Accounts payable	1,782	2,851
Accrued expenses and other current liabilities	3,758	2,715
Total current liabilities	5,540	5,566
Operating lease liabilities, noncurrent	544	541
Total liabilities	6,084	6,107
Commitments and contingencies (Note 9)
Stockholders’ equity
Preferred stock, par value of $0.00001 per share; 10,000,000 shares authorized at March 31, 2021 and December 31, 2020; no shares issued or outstanding as of March 31, 2021 and December 31, 2020
Additional paid-in capital	270,206	269,175
Accumulated deficit	(117,705)	(104,360)
Accumulated other comprehensive income (loss)	70	674
Total stockholders’ equity	152,571	165,489
Total liabilities and stockholders' equity	$ 158,655	$ 171,596

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.00001	$ 0.00001
Preferred stock, authorized	10,000,000	10,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Common stock, par value	$ 0.00001	$ 0.00001
Common stock, authorized	300,000,000	300,000,000
Common stock, issued	25,261,832	25,261,832
Common stock, outstanding	25,261,832	25,261,832

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating expenses
Research and development	$ 9,990	$ 4,707
General and administrative	3,562	1,123
Total operating expenses	13,552	5,830
Loss from operations	(13,552)	(5,830)
Other income (expense), net
Interest income, net	39
Foreign exchange transaction gain, net	168	156
Total other income (expense), net	207	156
Net loss	$ (13,345)	$ (5,674)
Net loss per common share, basic and diluted	$ (0.53)	$ (21.83)
Weighted-average number of shares used in computing net loss per common share, basic and diluted	25,261,832	259,966
Other comprehensive loss
Net loss	$ (13,345)	$ (5,674)
Currency translation loss	(524)	(210)
Unrealized loss on marketable securities	(80)
Total comprehensive loss	$ (13,949)	$ (5,884)

Condensed Consolidated Statem_2

Condensed 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	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Other Comprehensive Loss
Beginning balance at Dec. 31, 2019	$ (71,148)				$ 826	$ (69,523)	$ (2,451)
Beginning balance (in shares) at Dec. 31, 2019		684,068	4,125,056
Beginning balance at Dec. 31, 2019		$ 13,414	$ 106,205
Beginning balance (in shares) at Dec. 31, 2019				259,966
Currency translation loss	(210)						(210)
Net loss	(5,674)					(5,674)
Ending balance at Mar. 31, 2020	(77,032)				826	(75,197)	(2,661)
Ending balance (in shares) at Mar. 31, 2020		684,068	4,125,056
Ending balance at Mar. 31, 2020		$ 13,414	$ 106,205
Ending balance (in shares) at Mar. 31, 2020				259,966
Beginning balance at Dec. 31, 2020	165,489				269,175	(104,360)	674
Beginning balance (in shares) at Dec. 31, 2020				25,261,832
Stock-based compensation expense	1,031				1,031
Currency translation loss	(524)						(524)
Unrealized loss on marketable securities	(80)						(80)
Net loss	(13,345)					(13,345)
Ending balance at Mar. 31, 2021	$ 152,571				$ 270,206	$ (117,705)	$ 70
Ending balance (in shares) at Mar. 31, 2021				25,261,832

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net loss	$ (13,345,000)	$ (5,674,000)
Adjustment to reconcile net loss to net cash used in operating activities:
Depreciation	2,000
Stock-based compensation	1,031,000
Non-cash interest expense	(92,000)
Amortization of right of use lease asset	97,000	25,000
Accretion of lease liability	19,000
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(855,000)	309,000
Accounts payable	(1,069,000)	(1,717,000)
Accrued expenses and other current liabilities	1,002,000	(890,000)
Other assets, noncurrent	(822,000)
Operating lease liabilities	(119,000)	(31,000)
Net cash used in operating activities	(14,151,000)	(7,978,000)
Cash flows from investing activities:
Purchases of marketable securities	(74,566,000)
Purchases of property and equipment	(65,000)
Net cash used in investing activities	(74,631,000)
Cash flows from financing activities:
Proceeds from issuance of Series C preferred stock, net		39,668,000
Net cash provided by financing activities		39,668,000
Net increase (decrease) in cash, cash equivalents and restricted cash	(88,782,000)	31,690,000
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(604,000)	(210,000)
Cash, cash equivalents and restricted cash, beginning of period	163,836,000	11,525,000
Cash, cash equivalents and restricted cash, end of period	74,450,000	43,005,000
Components of cash, cash equivalents and restricted cash
Cash and cash equivalents	74,253,000	42,779,000
Restricted cash	197,000	226,000
Cash, cash equivalents and restricted cash, end of period	74,450,000	$ 43,005,000
Supplemental disclosures of cash flow information:
Cash paid for taxes	38,000
Supplemental disclosures of noncash activities:
Operating lease liabilities arising from obtaining right-of-use assets	$ 161,000

Description of Business, Organi

Description of Business, Organization and Liquidity	3 Months Ended
	Mar. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business, Organization and Liquidity	1. DESCRIPTION OF BUSINESS, ORGANIZATION AND LIQUIDITY Business and Organization Galecto, Inc., together with its consolidated subsidiaries, or 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. As of March 31, 2021, the Company’s wholly owned subsidiaries were PharmAkea, Inc. or PharmAkea, Galecto Securities Corporation and Galecto Biotech AB, a Swedish company. Galecto Biotech ApS, a Danish operating company, was Galecto Biotech AB’s wholly owned subsidiary. 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 The accompanying condensed The accompanying interim condensed consolidated financial statements as of March 31, 2021 and for the three months ended March 31, 2021 and 2020, and related interim information contained within the notes to the condensed consolidated financial statements, are unaudited. In management’s opinion, the unaudited interim condensed 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 of 2017. 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	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Other than noted below, there have been no changes to the significant accounting policies as disclosed in Note 2 to the Company’s annual consolidated financial statements for the year ended December 31, 2020 included in the Annual Report on Form 10-K filed with the SEC on March 29, 2021. Investments in Marketable Securities The Company invests excess cash balances in short-term and long-term marketable debt securities. The Company classifies investments in marketable debt securities as either held-to-maturity or available-for-sale based on facts and circumstances present at the time of purchase and re-evaluates classification at each balance sheet date. All investments in marketable debt securities at each balance sheet date presented, are generally considered as available-for-sale. Marketable debt securities with maturities of twelve months or less are classified as short-term investments and marketable debt securities with maturities greater than twelve months are classified based on their availability for use in current operations. The Company reports available-for-sale debt securities at fair value at each balance sheet date and includes any unrealized holding gains and losses (the adjustment to fair value), net of applicable taxes, in accumulated other comprehensive income (loss), a component of stockholders’ equity. Realized gains and losses are determined using the specific identification method and are included in other income (expense). If any adjustment to fair value reflects a decline in the value of the investment, the Company considers all available evidence to evaluate the extent to which the decline is “other than temporary,” including the intention to sell and, if so, marks the investment to market through a charge to the Company’s condensed consolidated statements of operations and comprehensive loss. Property and Equipment, Net Property and equipment are recorded at cost. Costs associated with maintenance and repairs are expensed as incurred. Depreciation is provided using the straight-line method over the estimated useful lives: Asset Category Useful Life Equipment 5-7 years Furniture and fixtures 5 years Leasehold improvements Lesser of 10 years or the remaining term of the respective lease 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 In December 2019, the FASB issued ASU No. 2019-12, Simplifying the Accounting for Income Taxes

Investments

Investments	3 Months Ended
	Mar. 31, 2021
Investments Debt And Equity Securities [Abstract]
Investments	3. INVESTMENTS Cash in excess of the Company’s immediate requirements is invested in accordance with the Company’s investment policy that primarily seeks to maintain adequate liquidity and preserve capital. The following table summarizes the Company’s interest-bearing investments, by category, as of March 31, 2021 (in thousands ): March 31, Investments - Current: 2021 Debt securities - available-for-sale $ 36,081 Total $ 36,081 Investments - Noncurrent: Debt securities - available-for-sale $ 38,576 Total $ 38,576 A summary of the Company’s available-for-sale investments as of March 31, 2021 consisted of the following (in thousands): At March 31, 2021 Cost Gross Unrealized Gross Unrealized Fair Investments - Current: Basis Gains Losses Value Corporate bonds $ 36,097 $ — $ (16 ) $ 36,081 Total $ 36,097 $ — $ (16 ) $ 36,081 Investments - Noncurrent: Corporate bonds $ 38,640 $ — $ (64 ) $ 38,576 Total $ 38,640 $ — $ (64 ) $ 38,576 The amortized cost and fair value of the Company’s available-for-sale investments, by contract maturity, as of March 31, 2021 consisted of the following (in thousands): Amortized Fair Cost Value Due in one year or less $ 36,097 $ 36,081 Due after one year through five years 38,640 38,576 Total $ 74,737 $ 74,657 The Company had no marketable securities as of December 31, 2020.

Property and Equipment, Net

Property and Equipment, Net	3 Months Ended
	Mar. 31, 2021
Property Plant And Equipment [Abstract]
Property and Equipment, Net	4. PROPERTY AND EQUIPMENT, NET Property and equipment as of March 31, 2021 consisted of the following (in thousands): March 31, 2021 Equipment $ 65 Total property and equipment 65 Less: accumulated depreciation (2 ) Property and equipment, net $ 63 Depreciation expense for the three months ended March 31, 2021 was $2,000. The Company had no property and equipment as of December 31, 2020.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	5. 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 classified its debt securities within Level 2 because their fair values are determined using alternative pricing sources or models that utilized market observable inputs. A summary of the assets that are measured at fair value as of March 31, 2021 and December 31, 2020 is as follows (in thousands): Fair Value Measurement at March 31, 2021 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) $ 66,637 $ 66,637 $ — $ — Debt securities 74,657 — 74,657 — Total $ 141,294 $ 66,637 $ 74,657 $ — 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 condensed consolidated balance sheets and are recognized at fair value.

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	3 Months Ended
	Mar. 31, 2021
Prepaid Expense And Other Assets Current [Abstract]
Prepaid Expenses and Other Current Assets	6. PREPAID EXPENSES AND OTHER CURRENT ASSETS Prepaid expenses and other current assets consist of the following (in thousands): March 31, December 31, 2021 2020 Contract research and development costs $ 3,792 $ 1,620 Prepaid insurance costs 1,166 1,642 Research and development tax credit receivable 868 1,808 Value-added tax refund receivable 310 401 Other 432 242 Total prepaid expenses and other current assets $ 6,568 $ 5,713

Leases

Leases	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Leases	7. LEASES The Company is party to four 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 the three months ended March 31, 2021 and 2020 was $98,000 and $42,000, respectively. The Company has an operating lease for its corporate headquarters in Copenhagen, Denmark for office space that expires in October 2021 and has a renewal option which expires in October 2024. 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. In January 2021, the Company entered into an operating lease agreement in Stevenage, United Kingdom, for laboratory space. Quantitative information regarding the Company’s leases for the three months ended March 31, 2021 and 2020 is as follows: March 31, Lease Cost 2021 2020 Operating lease cost (in thousands) $ 119 $ 31 Other Information Operating cash flows paid for amounts included in the measurement of lease liabilities (in thousands) $ 119 $ 31 Operating lease liabilities arising from obtaining right-of-use assets (in thousands) $ 161 $ — Weighted average remaining lease term (years) 2.6 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. Future lease payments under noncancelable leases are as follows at March 31, 2021 (in thousands): Operating Future Lease Payments Leases 2021 (excluding the period ended March 31, 2021) $ 370 2022 380 2023 200 2024 116 2025 — Total lease payments 1,066 Less: imputed interest (107 ) Total lease liabilities $ 959 In April 2021, the Company entered into an operating lease agreement for its corporate headquarters in Copenhagen, Denmark, for office space, which will supersede the Company’s existing lease agreement. The lease agreement expires in January 2025 and additional lease payments of $286,000 are not included in the future lease payments above.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	3 Months Ended
	Mar. 31, 2021
Payables And Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	8. ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES Accrued expenses and other current liabilities consist of the following (in thousands): March 31, December 31, 2021 2020 Contract research and development costs $ 1,982 $ 967 Employee compensation costs 904 1,031 Lease liabilities 415 374 Other liabilities 457 343 Total accrued expenses and other current liabilities $ 3,758 $ 2,715

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. COMMITMENTS AND CONTINGENCIES The Company’s commitments and contingencies are disclosed in Note 8 of the audited consolidated financial statements as of and for the year ended December 31, 2020, filed with the SEC on March 29, 2021. There have been no material changes to the Company’s commitments and contingencies since the date of such financial statements. Further, the Company’s commitments related to lease agreements are disclosed in Note 7 to our unaudited interim condensed consolidated financial statements.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	10. STOCK-BASED COMPENSATION Employee equity plan In March 2020, the Company replaced the 2013 Option Program, or (“2013 Plan”), 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 1st each year. At March 31, 2021, the Company had 1,925,949 options available for future grant under the 2020 Equity Plan. 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, 2019 304,142 $ 5.58 — — Granted 2,235,285 4.67 — — Exercised (1,016 ) 1.95 — — Outstanding at December 31, 2020 2,538,411 $ 4.67 8.8 $ 20,009,769 Granted 936,000 12.89 — — Outstanding at March 31, 2021 3,474,411 $ 6.88 8.9 $ 5,392,883 Vested and expected to vest at March 31, 2021 3,170,269 $ 7.03 9.4 $ 5,185,488 Exercisable at March 31, 2021 800,778 $ 3.38 6.7 $ 2,227,144 The weighted-average grant date fair value of all stock options granted for the three months ended March 31, 2021 was $9.52. The intrinsic value at March 31, 2021 was based on the closing price of the Company’s common stock on that date of $6.08 per share. Stock-based compensation The grant date fair value of stock options vested during the three months ended March 31, 2021 was $0.2 million. Total unrecognized compensation expense related to unvested options granted under the Company’s stock-based compensation plan was $14.4 million at March 31, 2021, which is expected to be recognized over a weighted average period of 3.5 years. The Company recorded stock-based compensation expense related to the issuance of stock as follows (in thousands): Three Months Ended March 31, 2021 Research and development $ 407 General and administrative 624 Total stock-based compensation $ 1,031 There was no stock-based compensation expense during the three months ended March 31, 2020. The fair values of the options granted were estimated based on the Black-Scholes model, using the following assumptions: Three Months Ended March 31, 2021 Risk-free interest rate 0.5 % Expected term (in years) 6.1 Expected volatility 90.5 % Expected dividend yield —

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Net Loss Per Share	11. NET LOSS PER SHARE Basic and diluted net loss per share is calculated as follows (in thousands except share and per share amounts): March 31, 2021 2020 Net loss $ (13,345 ) $ (5,674 ) Net loss per common share, basic and diluted $ (0.53 ) $ (21.83 ) Weighted-average number of shares used in computing net loss per common share, basic and diluted 25,261,832 259,966 The following outstanding potentially dilutive securities have been excluded from the calculation of diluted net loss per share, as their effect is anti-dilutive: March 31, 2021 2020 Stock options to purchase common stock 3,474,411 304,142

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	12. SUBSEQUENT EVENTS The Company has evaluated subsequent events through the date on which the unaudited interim condensed consolidated financial statements were issued. The Company has concluded that no subsequent events have occurred that require disclosure to the unaudited interim condensed consolidated financial statements.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Investments in Marketable Securities	Investments in Marketable Securities The Company invests excess cash balances in short-term and long-term marketable debt securities. The Company classifies investments in marketable debt securities as either held-to-maturity or available-for-sale based on facts and circumstances present at the time of purchase and re-evaluates classification at each balance sheet date. All investments in marketable debt securities at each balance sheet date presented, are generally considered as available-for-sale. Marketable debt securities with maturities of twelve months or less are classified as short-term investments and marketable debt securities with maturities greater than twelve months are classified based on their availability for use in current operations. The Company reports available-for-sale debt securities at fair value at each balance sheet date and includes any unrealized holding gains and losses (the adjustment to fair value), net of applicable taxes, in accumulated other comprehensive income (loss), a component of stockholders’ equity. Realized gains and losses are determined using the specific identification method and are included in other income (expense). If any adjustment to fair value reflects a decline in the value of the investment, the Company considers all available evidence to evaluate the extent to which the decline is “other than temporary,” including the intention to sell and, if so, marks the investment to market through a charge to the Company’s condensed consolidated statements of operations and comprehensive loss.
Property and Equipment, Net	Property and Equipment, Net Property and equipment are recorded at cost. Costs associated with maintenance and repairs are expensed as incurred. Depreciation is provided using the straight-line method over the estimated useful lives: Asset Category Useful Life Equipment 5-7 years Furniture and fixtures 5 years Leasehold improvements Lesser of 10 years or the remaining term of the respective lease
Recently issued accounting standards	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 In December 2019, the FASB issued ASU No. 2019-12, Simplifying the Accounting for Income Taxes

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Summary of Estimated Useful Life of Asset	Property and equipment are recorded at cost. Costs associated with maintenance and repairs are expensed as incurred. Depreciation is provided using the straight-line method over the estimated useful lives: Asset Category Useful Life Equipment 5-7 years Furniture and fixtures 5 years Leasehold improvements Lesser of 10 years or the remaining term of the respective lease

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2021
Investments Debt And Equity Securities [Abstract]
Summary of Investments by Category	The following table summarizes the Company’s interest-bearing investments, by category, as of March 31, 2021 (in thousands ): March 31, Investments - Current: 2021 Debt securities - available-for-sale $ 36,081 Total $ 36,081 Investments - Noncurrent: Debt securities - available-for-sale $ 38,576 Total $ 38,576
Summary of Available-for-Sale Investments	A summary of the Company’s available-for-sale investments as of March 31, 2021 consisted of the following (in thousands): At March 31, 2021 Cost Gross Unrealized Gross Unrealized Fair Investments - Current: Basis Gains Losses Value Corporate bonds $ 36,097 $ — $ (16 ) $ 36,081 Total $ 36,097 $ — $ (16 ) $ 36,081 Investments - Noncurrent: Corporate bonds $ 38,640 $ — $ (64 ) $ 38,576 Total $ 38,640 $ — $ (64 ) $ 38,576
Summary of Amortized Cost and Fair Value of Available-for-Sale Investments by Contract Maturity	The amortized cost and fair value of the Company’s available-for-sale investments, by contract maturity, as of March 31, 2021 consisted of the following (in thousands): Amortized Fair Cost Value Due in one year or less $ 36,097 $ 36,081 Due after one year through five years 38,640 38,576 Total $ 74,737 $ 74,657

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	3 Months Ended
	Mar. 31, 2021
Property Plant And Equipment [Abstract]
Summary of Property and Equipment	Property and equipment as of March 31, 2021 consisted of the following (in thousands): March 31, 2021 Equipment $ 65 Total property and equipment 65 Less: accumulated depreciation (2 ) Property and equipment, net $ 63

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Summary of Assets Measured at Fair Value	A summary of the assets that are measured at fair value as of March 31, 2021 and December 31, 2020 is as follows (in thousands): Fair Value Measurement at March 31, 2021 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) $ 66,637 $ 66,637 $ — $ — Debt securities 74,657 — 74,657 — Total $ 141,294 $ 66,637 $ 74,657 $ — 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 condensed consolidated balance sheets and are recognized at fair value.

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	3 Months Ended
	Mar. 31, 2021
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): March 31, December 31, 2021 2020 Contract research and development costs $ 3,792 $ 1,620 Prepaid insurance costs 1,166 1,642 Research and development tax credit receivable 868 1,808 Value-added tax refund receivable 310 401 Other 432 242 Total prepaid expenses and other current assets $ 6,568 $ 5,713

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2021
Leases [Abstract]
Quantitative Information Regarding Leases	Quantitative information regarding the Company’s leases for the three months ended March 31, 2021 and 2020 is as follows: March 31, Lease Cost 2021 2020 Operating lease cost (in thousands) $ 119 $ 31 Other Information Operating cash flows paid for amounts included in the measurement of lease liabilities (in thousands) $ 119 $ 31 Operating lease liabilities arising from obtaining right-of-use assets (in thousands) $ 161 $ — Weighted average remaining lease term (years) 2.6 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 March 31, 2021 (in thousands): Operating Future Lease Payments Leases 2021 (excluding the period ended March 31, 2021) $ 370 2022 380 2023 200 2024 116 2025 — Total lease payments 1,066 Less: imputed interest (107 ) Total lease liabilities $ 959

Accrued Expenses And Other Cu_2

Accrued Expenses And Other Current Liabilities (Tables)	3 Months Ended
	Mar. 31, 2021
Payables And Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following (in thousands): March 31, December 31, 2021 2020 Contract research and development costs $ 1,982 $ 967 Employee compensation costs 904 1,031 Lease liabilities 415 374 Other liabilities 457 343 Total accrued expenses and other current liabilities $ 3,758 $ 2,715

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2021
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, 2019 304,142 $ 5.58 — — Granted 2,235,285 4.67 — — Exercised (1,016 ) 1.95 — — Outstanding at December 31, 2020 2,538,411 $ 4.67 8.8 $ 20,009,769 Granted 936,000 12.89 — — Outstanding at March 31, 2021 3,474,411 $ 6.88 8.9 $ 5,392,883 Vested and expected to vest at March 31, 2021 3,170,269 $ 7.03 9.4 $ 5,185,488 Exercisable at March 31, 2021 800,778 $ 3.38 6.7 $ 2,227,144
Summary of Stock-based Compensation Expenses Related to Issuance of Stock	The Company recorded stock-based compensation expense related to the issuance of stock as follows (in thousands): Three Months Ended March 31, 2021 Research and development $ 407 General and administrative 624 Total stock-based compensation $ 1,031
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: Three Months Ended March 31, 2021 Risk-free interest rate 0.5 % Expected term (in years) 6.1 Expected volatility 90.5 % Expected dividend yield —

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2021
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): March 31, 2021 2020 Net loss $ (13,345 ) $ (5,674 ) Net loss per common share, basic and diluted $ (0.53 ) $ (21.83 ) Weighted-average number of shares used in computing net loss per common share, basic and diluted 25,261,832 259,966
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: March 31, 2021 2020 Stock options to purchase common stock 3,474,411 304,142

Description of Business, Orga_2

Description of Business, Organization and Liquidity - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Description Of Business Organization And Liquidity [Line Items]
Accumulated deficit	$ 117,705		$ 104,360
Net loss	(13,345)	$ (5,674)
Cash, cash equivalents and marketable securities	148,900
Cash and cash equivalents	74,253	42,779	163,582
Current assets	116,902		169,295
Current liabilities	5,540		$ 5,566
Clinical Development and Corporate General and Administrative Activities
Description Of Business Organization And Liquidity [Line Items]
Net loss	$ (14,200)	$ (8,000)

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Summary of Estimated Useful Life of Asset (Detail)	3 Months Ended
	Mar. 31, 2021
Equipment | Minimum
Property Plant And Equipment [Line Items]
Estimated useful life of asset	5 years
Equipment | Maximum
Property Plant And Equipment [Line Items]
Estimated useful life of asset	7 years
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Estimated useful life of asset	5 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Estimated useful life of asset	Lesser of 10 years or the remaining term of the respective lease

Investments - Summary of Invest

Investments - Summary of Investments by Category (Details) $ in Thousands	Mar. 31, 2021USD ($)
Investments - Current:
Debt securities - available-for-sale	$ 36,081
Total	36,081
Investments - Noncurrent:
Debt securities - available-for-sale	38,576
Total	$ 38,576

Investments - Summary of Availa

Investments - Summary of Available-for-Sale Investments (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Schedule of Available for Sale Securities [Line Items]
Cost Basis	$ 74,737,000
Fair Value	$ 74,657,000	$ 0
Debt Securities, Available-for-sale, Type [Extensible List]	us-gaap:CorporateDebtSecuritiesMember
Investments - Current
Schedule of Available for Sale Securities [Line Items]
Cost Basis	$ 36,097,000
Gross Unrealized Losses	(16,000)
Fair Value	36,081,000
Investments - Noncurrent
Schedule of Available for Sale Securities [Line Items]
Cost Basis	38,640,000
Gross Unrealized Losses	(64,000)
Fair Value	$ 38,576,000

Investments - Summary of Amorti

Investments - Summary of Amortized Cost and Fair Value of Available-for-Sale Investments by Contract Maturity (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Investments Debt And Equity Securities [Abstract]
Amortized Cost, Due in one year or less	$ 36,097,000
Amortized Cost, Due after one year through five years	38,640,000
Cost Basis	74,737,000
Fair Value, Due in one year or less	36,081,000
Fair Value, Due after one year through five years	38,576,000
Fair Value, Total	$ 74,657,000	$ 0
Debt Securities, Available-for-sale, Maturity Allocation [Extensible List]	us-gaap:DebtSecuritiesMaturityAllocationContractualMaturityMember

Investments - Additional Inform

Investments - Additional Information (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Investments Debt And Equity Securities [Abstract]
Marketable securities	$ 74,657,000	$ 0

Property and Equipment, Net - S

Property and Equipment, Net - Summary of Property and Equipment (Details) $ in Thousands	Mar. 31, 2021USD ($)
Property Plant And Equipment [Line Items]
Total property and equipment	$ 65
Less: accumulated depreciation	(2)
Property and equipment, net	63
Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	$ 65

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Depreciation expense	$ 2,000
Property and equipment		$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Assets Measured at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	$ 141,294	$ 142,904
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	66,637	142,904
Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	74,657
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	66,637	142,904
Level 1 | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	66,637	$ 142,904
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	74,657
Level 2 | Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets fair value	$ 74,657

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets - Schedule of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Prepaid Expense And Other Assets Current [Abstract]
Contract research and development costs	$ 3,792	$ 1,620
Prepaid insurance costs	1,166	1,642
Research and development tax credit receivable	868	1,808
Value-added tax refund receivable	310	401
Other	432	242
Total prepaid expenses and other current assets	$ 6,568	$ 5,713

Leases - Additional Information

Leases - Additional Information (Details)	1 Months Ended		3 Months Ended
	Apr. 30, 2021USD ($)	Jun. 30, 2020ft²	Mar. 31, 2021USD ($)Facility	Mar. 31, 2020USD ($)
Leases [Line Items]
Number of office and laboratory space | Facility			4
Rent expense			$ 98,000	$ 42,000
Future lease payments			$ 1,066,000
Denmark
Leases [Line Items]
Operating lease, expiration date			Oct. 31, 2021
Lease renewal option expiration date			Oct. 31, 2024
Description of lease, option to extend			renewal option which expires in October 2024.
Operating lease, option to extend			true
Office space under operating lease | ft²		1,300
Operating lease description			In April 2021, the Company entered into an operating lease agreement for its corporate headquarters in Copenhagen, Denmark, for office space, which will supersede the Company’s existing lease agreement. The lease agreement expires in January 2025
Denmark | Subsequent Event
Leases [Line Items]
Operating lease, expiration date	Jan. 31, 2025
Lease renewal option expiration date	Jan. 31, 2025
Future lease payments	$ 286,000
United Kingdom
Leases [Line Items]
Operating lease, expiration date			Aug. 31, 2022
Sweden
Leases [Line Items]
Operating lease, expiration date			Sep. 30, 2022

Leases - Quantitative Informati

Leases - Quantitative Information Regarding Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Lease Cost
Operating lease cost (in thousands)	$ 119	$ 31
Operating cash flows paid for amounts included in the measurement of lease liabilities (in thousands)	119	$ 31
Operating lease liabilities arising from obtaining right-of-use assets (in thousands)	$ 161
Weighted average remaining lease term (years)	2 years 7 months 6 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	Mar. 31, 2021USD ($)
Future Lease Payments
2021 (excluding the period ended March 31, 2021)	$ 370
2022	380
2023	200
2024	116
Total lease payments	1,066
Less: imputed interest	(107)
Total lease liabilities	$ 959

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Contract research and development costs	$ 1,982	$ 967
Employee compensation costs	904	1,031
Lease liabilities	$ 415	$ 374
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	glto:LeaseLiabilitiesMember	glto:LeaseLiabilitiesMember
Other liabilities	$ 457	$ 343
Total accrued expenses and other current liabilities	$ 3,758	$ 2,715

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended		12 Months Ended
	Oct. 31, 2020	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, granted			936,000		2,235,285
Stock-based compensation expense			$ 1,031,000	$ 0
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value of stock options granted			$ 9.52
Intrinsic value per share of stock options			$ 6.08
Fair value of stock options vested			$ 200,000
2020 Plan | Unvested Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense			$ 14,400,000
Unrecognized compensation expense that is expected to be recognized over a weighted-average period			3 years 6 months
2020 Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock options allowed to award						839,494
Number of options, granted		304,142
Stock options, expiration period		10 years
2020 Plan | Maximum | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock options allowed to award		1,740,325		1,740,325
Stock options, vesting period		4 years
2020 Plan | Minimum | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, vesting period		3 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			1,925,949
2020 Equity Incentive Plan | Maximum | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock options allowed to award	1,625,858

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Options Activity (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options, Outstanding	2,538,411	304,142
Number of Options, Granted	936,000	2,235,285
Number of Options, Exercised		(1,016)
Number of Options, Outstanding	3,474,411	2,538,411
Number of Options, Vested and expected to vest	3,170,269
Number of Options, Exercisable	800,778
Weighted average exercise price per share, Outstanding	$ 4.67	$ 5.58
Weighted average exercise price per share, Granted	12.89	4.67
Weighted average exercise price per share, Exercised		1.95
Weighted average exercise price per share, Outstanding	6.88	$ 4.67
Weighted average exercise price per share, Vested and expected to vest	7.03
Weighted average exercise price per share, Exercisable	$ 3.38
Weighted average remaining contractual term (in years), Outstanding	8 years 10 months 24 days	8 years 9 months 18 days
Weighted average remaining contractual term (in years), Vested and expected to vest	9 years 4 months 24 days
Weighted average remaining contractual term (in years), Exercisable	6 years 8 months 12 days
Aggregate intrinsic value, Outstanding	$ 20,009,769
Aggregate intrinsic value, Outstanding	5,392,883	$ 20,009,769
Aggregate intrinsic value, Vested and expected to vest	5,185,488
Aggregate intrinsic value, Exercisable	$ 2,227,144

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Stock-based Compensation Expenses Related to Issuance of Stock (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 1,031,000	$ 0
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	407,000
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 624,000

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Fair Value Assumptions of Options Granted Estimated Based on Black-Scholes Model (Details)	3 Months Ended
	Mar. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Risk-free interest rate	0.50%
Expected term (in years)	6 years 1 month 6 days
Expected volatility	90.50%

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	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net loss	$ (13,345)	$ (5,674)
Net loss per common share, basic and diluted	$ (0.53)	$ (21.83)
Weighted-average number of shares used in computing net loss per common share, basic and diluted	25,261,832	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	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
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	3,474,411	304,142