Cover
| Cover - USD ($) $ in Thousands | 12 Months Ended | ||
| Dec. 31, 2021 | Apr. 27, 2022 | Jun. 30, 2021 | |
| Cover [Abstract] | |||
| Document Type | 10-K/A | ||
| Amendment Flag | true | ||
| Document Period End Date | Dec. 31, 2021 | ||
| Document Fiscal Year Focus | 2021 | ||
| Document Fiscal Period Focus | FY | ||
| Entity Registrant Name | CATALYST PHARMACEUTICALS, INC. | ||
| Entity Central Index Key | 0001369568 | ||
| Current Fiscal Year End Date | --12-31 | ||
| Entity Voluntary Filers | No | ||
| Entity Well-known Seasoned Issuer | No | ||
| Entity Current Reporting Status | Yes | ||
| Entity Shell Company | false | ||
| Entity Filer Category | Accelerated Filer | ||
| Entity Emerging Growth Company | false | ||
| Entity Small Business | false | ||
| Entity Address, State or Province | FL | ||
| Entity Interactive Data Current | Yes | ||
| Title of 12(b) Security | Common Stock | ||
| Entity Common Stock, Shares Outstanding | 102,780,151 | ||
| Entity Tax Identification Number | 76-0837053 | ||
| Entity Incorporation, State or Country Code | DE | ||
| Entity Address, Address Line One | 355 Alhambra Circle | ||
| Entity Address, Address Line Two | Suite 801 | ||
| Entity Address, City or Town | Coral Gables | ||
| Entity Address, Postal Zip Code | 33134 | ||
| City Area Code | 305 | ||
| Local Phone Number | 420-3200 | ||
| Document Annual Report | true | ||
| Document Transition Report | false | ||
| Entity File Number | 001-33057 | ||
| Entity Public Float | $ 551,581,521 | ||
| ICFR Auditor Attestation Flag | true | ||
| Amendment Description | This Amendment No. 1 on Form 10-K/A (“Form 10-K/A”) is being filed by Catalyst Pharmaceuticals, Inc. in order to disclose information required by Items 10, 11, 12, 13 and 14 of Part III of Form 10-K, which information was previously omitted from Catalyst’s Form 10-K for the fiscal year ended December 31, 2021 (“2021 Original Form 10-K”) in reliance on Instruction G to Form 10-K . The 2021 Original Form 10-K was filed with the SEC on March 16, 2022. Catalyst has elected to postpone its 2022 annual meeting of stockholders until August 25, 2022. As a result, Catalyst will not be filing its definitive proxy statement for the 2022 annual stockholders’ meeting within 120 days of the end of its most recent fiscal year (as required under Instruction G to Form 10-K). Therefore, Catalyst is filing this Form 10-K/A in order to incorporate information that would have been contained in the definitive proxy statement into the 2021 Original Form 10-K. Catalyst is also filing as Exhibits to the Form 10-K/A certifications with respect to this filing by its principal executive officer and principal financial officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002; accordingly, Item 15 of Part IV has also been amended to reflect the filing of these new exhibits. Because no financial statements are being filed in this Form 10-K/A, and this Form 10-K/A 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 certifications have been omitted. Catalyst is also not including the certifications required under Section 906 of the Sarbanes-Oxley Act of 2002, since no financial statements are being filed with this Form 10-K/A. This Form 10-K/A is limited in scope to the items identified above and should be read in conjunction with the 2021 Original Form 10-K and Catalyst’s other filings with the SEC. This Form 10-K/A does not reflect events occurring after the filing of the 2021 Original Form 10-K or modify or update those disclosures affected by subsequent events. Consequently, all other information is unchanged and reflects the disclosures made at the time of the filing of the 2021 Original Form 10-K. | ||
| Auditor Name | Grant Thornton LLP | ||
| Auditor Firm ID | 248 | ||
| Auditor Location | Miami, FL |