| Document And Entity Information - USD ($) $ in Millions | Dec. 31, 2021 | Apr. 26, 2022 | Jun. 30, 2021 |
| Document Information [Line Items] | |||
| Entity, Registrant Name | PLX PHARMA INC. | ||
| Document, Type | 10-K/A | ||
| Document, Annual Report | true | ||
| Document, Period End Date | Dec. 31, 2021 | ||
| Current Fiscal Year End Date | --12-31 | ||
| Document, Fiscal Period Focus | FY | ||
| Document, Fiscal Year Focus | 2021 | ||
| Document, Transition Report | false | ||
| Entity, File Number | 001-36351 | ||
| Entity, Incorporation, State or Country Code | DE | ||
| Entity, Tax Identification Number | 46-4995704 | ||
| Entity, Address, Address Line One | 9 Fishers Lane, Suite E | ||
| Entity, Address, City or Town | Sparta | ||
| Entity, Address, State or Province | NJ | ||
| Entity, Address, Postal Zip Code | 07871 | ||
| City Area Code | 973 | ||
| Local Phone Number | 409-6541 | ||
| Title of 12(b) Security | Common Stock, $0.001 par value | ||
| Trading Symbol | PLXP | ||
| Security Exchange Name | NASDAQ | ||
| Entity, Well-known Seasoned Issuer | No | ||
| Entity, Voluntary Filers | No | ||
| Entity, Current Reporting Status | Yes | ||
| Entity, Interactive Data, Current | Yes | ||
| Entity, Filer Category | Non-accelerated Filer | ||
| Entity, Small Business | true | ||
| Entity, Emerging Growth Company | false | ||
| ICFR Auditor Attestation Flag | false | ||
| Entity, Shell Company | false | ||
| Entity, Public Float | $ 335.7 | ||
| Entity, Common Stock Shares, Outstanding | 27,539,229 | ||
| Auditor Firm ID | 688 | ||
| Auditor Name | Marcum LLP | ||
| Auditor Location | New York, NY | ||
| Amendment Description | The purpose of this Amendment No. 1 on Form 10-K/A (the “Amendment”) is to amend and restate Part III, Items 10 through 14, and to update the Exhibit index contained in Part IV, Item 15, of the previously filed Annual Report on Form 10-K of PLx Pharma Inc. (the “Company”) for the year ended December 31, 2021 (“Fiscal 2021”), filed with the Securities and Exchange Commission (the “SEC”) on March 11, 2022 (the “Original Form 10-K”), to include information previously omitted in reliance on General Instruction G to Form 10-K, which provides that registrants may incorporate by reference certain information from a definitive proxy statement prepared in connection with the election of directors. The Company has determined to include such Part III information by amendment of the Original Form 10-K rather than incorporation by reference to the proxy statement. Accordingly, Part III of the Original Form 10-K is hereby amended and restated as set forth below. As a result of this Amendment, the Company is also filing the certifications required under Section 302 of the Sarbanes-Oxley Act of 2002 as exhibits to this Amendment. Except as described above, no other changes have been made to the Original Form 10-K. Among other things, forward-looking statements made in the Original Form 10-K have not been revised to reflect events that occurred or facts that became known to us after the filing of the Original Form 10-K, and such forward-looking statements should be read in their historical context. | ||
| Amendment Flag | true | ||
| Entity, Central Index Key | 0001497504 |
