| Document and Entity Information | Oct. 07, 2024 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 07, 2024 |
| Entity Registrant Name | GALECTO, INC. |
| Entity Central Index Key | 0001800315 |
| Entity Emerging Growth Company | true |
| Current Fiscal Year End Date | --12-31 |
| Entity Ex Transition Period | false |
| Entity File Number | 001-39655 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 37-1957007 |
| Entity Address, Address Line One | 75 State Street |
| Entity Address, Address Line Two | Suite 100 |
| Entity Address, City or Town | Boston |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02109 |
| City Area Code | +45 |
| Local Phone Number | 70 70 52 10 |
| Title of 12(b) Security | Common Stock, $0.00001 par value per share |
| Trading Symbol | GLTO |
| Security Exchange Name | NASDAQ |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Pro Forma Condensed Consolidated Balance Sheet $ in Thousands | Jun. 30, 2024 USD ($) |
| Current assets | |
| Cash and cash equivalents | $ 22,862 |
| Prepaid expenses and other current assets | 2,306 |
| Total current assets | 25,168 |
| Operating lease right-of-use asset | 76 |
| Equipment, net | 67 |
| Other assets, non-current | 1,986 |
| Total assets | 27,297 |
| Current liabilities | |
| Accounts payable | 724 |
| Accrued expenses and other current liabilities | 2,985 |
| Total current liabilities | 3,709 |
| Total liabilities | 3,709 |
| Mezzanine equity | |
| Preferred stock, par value of $0.00001 per share; 10,000,000 shares authorized at June 30, 2024; no shares issued or outstanding as of June 30, 2024, actual; 161 shares issued and outstanding as of June 30, 2024, pro forma | |
| Stockholders’ equity | |
| Common stock, par value of $0.00001 per share; 300,000,000 shares authorized at June 30, 2024; 1,084,841 issued and outstanding at June 30, 2024; actual, 1,147,435 issued and outstanding at June 30, 2024, pro forma | |
| Additional paid-in capital | 290,291 |
| Accumulated deficit | (266,900) |
| Accumulated other comprehensive gain | 197 |
| Total stockholders’ equity | 23,588 |
| Total liabilities and stockholders' equity | 27,297 |
| Pro Forma | |
| Current assets | |
| Cash and cash equivalents | 20,182 |
| Prepaid expenses and other current assets | 2,306 |
| Total current assets | 22,488 |
| Operating lease right-of-use asset | 76 |
| Equipment, net | 67 |
| Other assets, non-current | 1,986 |
| Total assets | 24,617 |
| Current liabilities | |
| Accounts payable | 724 |
| Accrued expenses and other current liabilities | 2,985 |
| Total current liabilities | 3,709 |
| Total liabilities | 3,709 |
| Mezzanine equity | |
| Preferred stock, par value of $0.00001 per share; 10,000,000 shares authorized at June 30, 2024; no shares issued or outstanding as of June 30, 2024, actual; 161 shares issued and outstanding as of June 30, 2024, pro forma | 1,876 |
| Stockholders’ equity | |
| Common stock, par value of $0.00001 per share; 300,000,000 shares authorized at June 30, 2024; 1,084,841 issued and outstanding at June 30, 2024; actual, 1,147,435 issued and outstanding at June 30, 2024, pro forma | |
| Additional paid-in capital | 291,023 |
| Accumulated deficit | (272,188) |
| Accumulated other comprehensive gain | 197 |
| Total stockholders’ equity | 20,908 |
| Total liabilities and stockholders' equity | 24,617 |
| Asset Acquisition Adjustments | |
| Current assets | |
| Cash and cash equivalents | (2,680) |
| Total current assets | (2,680) |
| Total assets | (2,680) |
| Mezzanine equity | |
| Preferred stock, par value of $0.00001 per share; 10,000,000 shares authorized at June 30, 2024; no shares issued or outstanding as of June 30, 2024, actual; 161 shares issued and outstanding as of June 30, 2024, pro forma | 1,876 |
| Stockholders’ equity | |
| Common stock, par value of $0.00001 per share; 300,000,000 shares authorized at June 30, 2024; 1,084,841 issued and outstanding at June 30, 2024; actual, 1,147,435 issued and outstanding at June 30, 2024, pro forma | |
| Additional paid-in capital | 732 |
| Accumulated deficit | (5,288) |
| Total stockholders’ equity | (2,680) |
| Total liabilities and stockholders' equity | $ (2,680) |
| Pro Forma Condensed Consolidated Balance Sheet (Parenthetical) | Jun. 30, 2024 $ / shares shares |
| Preferred stock, par value | $ / shares | $ 0.00001 |
| Preferred stock, authorized | 10,000,000 |
| Preferred stock, issued | 0 |
| Preferred stock, outstanding | 0 |
| Common stock, par value | $ / shares | $ 0.00001 |
| Common stock, authorized | 300,000,000 |
| Common stock, issued | 1,084,841 |
| Common stock, outstanding | 1,084,841 |
| Pro Forma | |
| Preferred stock, issued | 161 |
| Preferred stock, outstanding | 161 |
| Common stock, issued | 1,147,435 |
| Common stock, outstanding | 1,147,435 |
| Pro Forma Condensed Consolidated Statement of Operations and Comprehensive Loss - USD ($) $ in Thousands | 6 Months Ended | 12 Months Ended |
| Jun. 30, 2024 | Dec. 31, 2023 | |
| Operating expenses | ||
| Research and development | $ 4,297 | $ 23,770 |
| General and administrative | 6,053 | 12,687 |
| Restructuring costs | 968 | 3,448 |
| Total operating expenses | 11,318 | 39,905 |
| Loss from operations | (11,318) | (39,905) |
| Other income, net | ||
| Interest income, net | 470 | 1,689 |
| Gain on sale of equipment | 64 | |
| Foreign exchange transaction gain (loss), net | 75 | (197) |
| Total other income, net | 545 | 1,556 |
| Loss before income tax expense | (10,773) | |
| Income tax expense | 42 | |
| Net loss | (10,815) | (38,349) |
| Net loss attributable to common shares | $ (10,815) | $ (38,349) |
| Net loss per common share, basic | $ (9.97) | $ (36.08) |
| Net loss per common share, diluted | $ (9.97) | $ (36.08) |
| Weighted-average number of shares used in computing net loss per common share, basic | 1,084,565 | 1,062,872 |
| Weighted-average number of shares used in computing net loss per common share, diluted | 1,084,565 | 1,062,872 |
| Other comprehensive loss, net of tax | ||
| Currency translation gain (loss) | $ (217) | $ 393 |
| Unrealized gain on marketable securities | 34 | 231 |
| Other comprehensive gain (loss), net of tax | (183) | 624 |
| Total comprehensive loss | (10,998) | (37,725) |
| Pro Forma | ||
| Operating expenses | ||
| Research and development | 4,297 | 29,058 |
| General and administrative | 6,053 | 12,687 |
| Restructuring costs | 968 | 3,448 |
| Total operating expenses | 11,318 | 45,193 |
| Loss from operations | (11,318) | (45,193) |
| Other income, net | ||
| Interest income, net | 470 | 1,689 |
| Gain on sale of equipment | 64 | |
| Foreign exchange transaction gain (loss), net | 75 | (197) |
| Total other income, net | 545 | 1,556 |
| Loss before income tax expense | (10,773) | |
| Income tax expense | 42 | |
| Net loss | (10,815) | (43,637) |
| Net loss attributable to common shares | $ (9,487) | $ (38,189) |
| Net loss per common share, basic | $ (8.27) | $ (33.93) |
| Net loss per common share, diluted | $ (8.27) | $ (33.93) |
| Weighted-average number of shares used in computing net loss per common share, basic | 1,147,159 | 1,125,466 |
| Weighted-average number of shares used in computing net loss per common share, diluted | 1,147,159 | 1,125,466 |
| Net loss attributable to preferred shares | $ (1,328) | $ (5,448) |
| Net income (loss) per preferred share, basic | $ (8,270) | $ (33,932) |
| Net income (loss) per preferred share, diluted | $ (8,270) | $ (33,932) |
| Weighted-average number of shares used in computing net loss per preferred share, basic | 161 | 161 |
| Weighted-average number of shares used in computing net loss per preferred share, diluted | 161 | 161 |
| Other comprehensive loss, net of tax | ||
| Currency translation gain (loss) | $ (217) | $ 393 |
| Unrealized gain on marketable securities | 34 | 231 |
| Other comprehensive gain (loss), net of tax | (183) | 624 |
| Total comprehensive loss | (10,998) | (43,013) |
| Asset Acquisition Adjustments | ||
| Operating expenses | ||
| Research and development | 5,288 | |
| Total operating expenses | 5,288 | |
| Loss from operations | (5,288) | |
| Other income, net | ||
| Net loss | (5,288) | |
| Net loss attributable to common shares | $ 1,328 | $ 160 |
| Weighted-average number of shares used in computing net loss per common share, basic | 62,594 | 62,594 |
| Weighted-average number of shares used in computing net loss per common share, diluted | 62,594 | 62,594 |
| Net loss attributable to preferred shares | $ (1,328) | $ (5,448) |
| Weighted-average number of shares used in computing net loss per preferred share, basic | 161 | 161 |
| Weighted-average number of shares used in computing net loss per preferred share, diluted | 161 | 161 |
| Other comprehensive loss, net of tax | ||
| Total comprehensive loss | $ (5,288) |
| Basis of Presentation | 6 Months Ended |
| Jun. 30, 2024 | |
| Organization, Consolidation and Presentation of Financial Statements [Abstract] | |
| Basis of Presentation | 1. Basis of Presentation The unaudited pro forma condensed consolidated financial information was prepared with the Asset Purchase being accounted for as an asset acquisition by the Company under Accounting Standards Codification (“ASC”) Topic 805-50. The Company further concluded that the set of assets acquired in the transaction does not represent a business under Securities and Exchange Commission Regulation S-X Rule 11-01 . Upon completion of the Asset Purchase, the Company obtained control of assets consisting primarily of in-process research and development (IPR&D) related to Bridge Medicine’s BRM-1420 program. In accordance with U.S. GAAP, the Company must first assess whether an integrated set of assets and activities should be accounted for as an acquisition of a business or an asset acquisition. An initial screen test is completed to determine if substantially all of the fair value of the gross assets acquired is concentrated in a single asset or group of similar assets. If that screen is met, the set is not considered a business and is accounted for as an asset acquisition. The Company will account for the Asset Purchase as an asset acquisition as substantially all of the fair value of the gross assets being acquired is concentrated within Bridge Medicine’s programs and development candidates which are considered a group of similar assets. |
| Transaction Adjustments | 6 Months Ended |
| Jun. 30, 2024 | |
| Transaction Adjustments [Abstract] | |
| Transaction Adjustments | 2. Transaction Adjustments The unaudited pro forma condensed consolidated financial statements reflect the following notes and adjustments: (a) Represents the cash paid to Bridge Medicines to reimburse transaction costs as well as the estimated transaction costs associated with the Asset Purchase incurred by the Company. (b) Represents the fair value of the Preferred Stock Payment Shares issued to Bridge Medicines in consideration of the assets acquired in the Asset Purchase. (c) Represents the fair value of the Common Stock Payment Shares issued to Bridge Medicines in consideration of the assets acquired in the Asset Purchase. (d) Represents the earnings adjustments associated with pro forma adjustment (e). (e) Represents the expense to be recorded associated with the Asset Purchase. The assets acquired do not have an alternative future use to the Company as defined in Accounting Standards Codification (“ASC”) 730, Research and development . Accordingly, the Company recorded the fair value of the consideration transferred for the assets acquired, which is comprised of the cash paid for transaction costs under pro forma adjustment (a), and the fair value of the Payment Shares under pro forma adjustments (b) and (c), as Research and development expense as opposed to capitalizing the costs as an asset. (f) Represents the allocation of pro forma net loss between the pro forma common shares and pro forma preferred shares of the Company. The preferred shares participate in earnings and losses of the Company with the Common Stock and are therefore treated as a separate class of common stock for purposes of calculating net loss per share. Net loss per share is provided separately for each class of stock. Subject to receipt of Stockholder Approval, the preferred stock is convertible into common stock at a conversion ratio of 1-to-1,000 and participate in losses on an as-converted basis. Accordingly, the net loss per preferred share is 1,000 times the net loss per common share. (g) Represents the issuance of shares of Common Stock Payment Shares and Preferred Stock Payment Shares to Bridge Medicines in consideration of the assets acquired in the Asset Purchase. |
| Transaction Adjustments - Additional Information (Details) | Jun. 30, 2024 |
| Transaction Adjustments [Abstract] | |
| Preferred stock, conversion ratio | 0.001 |
