| Cover Page - USD ($) $ in Millions | 12 Months Ended | | |
| Dec. 31, 2023 | Apr. 15, 2024 | Jun. 30, 2023 |
| Document Information [Line Items] | | | |
| Document Type | 10-K/A | | |
| Amendment Flag | true | | |
| Document Annual Report | true | | |
| Document Transition Report | false | | |
| Entity Shell Company | false | | |
| Entity Current Reporting Status | Yes | | |
| Entity Voluntary Filers | No | | |
| Entity Well-known Seasoned Issuer | No | | |
| Entity Interactive Data Current | Yes | | |
| Document Period End Date | Dec. 31, 2023 | | |
| Document Fiscal Year Focus | 2023 | | |
| Document Fiscal Period Focus | FY | | |
| Current Fiscal Year End Date | --12-31 | | |
| ICFR Auditor Attestation Flag | false | | |
| Document Financial Statement Error Correction [Flag] | false | | |
| Entity Registrant Name | Landos Biopharma, Inc. | | |
| Entity Incorporation, State or Country Code | DE | | |
| Entity Address, Address Line One | P.O. Box 11239 | | |
| Entity Address, City or Town | Blacksburg | | |
| Entity Address, State or Province | VA | | |
| Entity Tax Identification Number | 81-5085535 | | |
| Entity Address, Postal Zip Code | 24062 | | |
| City Area Code | 540 | | |
| Local Phone Number | 218-2232 | | |
| Title of 12(b) Security | Common stock, par value $0.01 per share | | |
| Trading Symbol | LABP | | |
| Entity Public Float | | | $ 5.6 |
| Security Exchange Name | NASDAQ | | |
| Entity Filer Category | Non-accelerated Filer | | |
| Entity File Number | 001-39971 | | |
| Entity Small Business | true | | |
| Entity Central Index Key | 0001785345 | | |
| Entity Emerging Growth Company | true | | |
| Entity Ex Transition Period | false | | |
| Entity Common Stock, Shares Outstanding | | 3,119,226 | |
| Auditor Name | Ernst & Young LLP | | |
| Auditor Location | Raleigh, North Carolina | | |
| Auditor Firm ID | 42 | | |
| Amendment Description | Landos Biopharma, Inc. (“Landos,” “we,” “us,” “our” or the “Company”) is filing this Amendment No. 1 (the “Amendment”) to amend its Annual Report on Form 10-K for the fiscal year ended December 31, 2023 (File Number 001-39971) (the “Original Form 10-K Filing”), as filed by the Company with the Securities and Exchange Commission (the “SEC”) on March 21, 2024, solely for the purpose of amending Items 10 through 14 in Part III and Item 15 in Part IV. The information in Part III was previously omitted from the Original Form 10-K Filing in reliance on General Instruction G(3) to Form 10-K, which provides that registrants may incorporate by reference certain information from a definitive proxy statement filed with the SEC within 120 days after the end of the fiscal year covered by the report. On March 24, 2024, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Bespin Subsidiary, LLC, a Delaware corporation and a wholly owned subsidiary of Guarantor (“Parent”), Bespin Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Parent (“Merger Sub”), and solely for the limited purposes set forth therein, AbbVie Inc. (“AbbVie” or “Guarantor”), providing for, among other things, our merger with Merger Sub (the “Merger”), with Landos surviving the Merger as a wholly owned subsidiary of Parent. As a result, we do not expect to conduct a 2024 annual meeting of stockholders. See “Agreement and Plan of Merger” below for a description of the Merger Agreement. In accordance with, among other things, Rule 12b-15 under the Securities Exchange Act of 1934, as amended, each item of the Original Form 10-K Filing that is amended by the Amendment is also restated in its entirety, and the Amendment is accompanied by a currently dated certification on Exhibits 31.2 by the Company’s Chief Executive Officer (because no financial statements have been included in the Amendment and the Amendment does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4 and 5 of the certification have been omitted). The Amendment is being filed to: (i) delete the reference on the cover of the Original Form 10-K Filing to the incorporation by reference information from the Company’s definitive proxy statement, (ii) revise Part III, Items 10 through 14 of the Original Form 10-K Filing to include information previously omitted from the Original Form 10-K Filing and (iii) revise the Exhibit Index of the Original Form 10-K Filing to reflect the filing of the new certifications. No attempt has been made in the Amendment to modify or update the other disclosures presented in the Original Form 10-K Filing. The Amendment does not reflect events occurring after the filing of the Original Form 10-K Filing or modify or update those disclosures that may be affected by subsequent events, other than as expressly indicated in the Amendment. Accordingly, the Amendment should be read in conjunction with the Original Form 10-K Filing and the Company’s other filings with the SEC. | | |
