| Document and Entity Information - shares | 6 Months Ended | |
| Jun. 30, 2024 | Aug. 01, 2024 | |
| Document and Entity Information | ||
| Document Type | 10-Q/A | |
| Document Quarterly Report | true | |
| Document Transition Report | false | |
| Document Period End Date | Jun. 30, 2024 | |
| Securities Act File Number | 001-38223 | |
| Entity Registrant Name | RHYTHM PHARMACEUTICALS, INC. | |
| Entity Incorporation, State or Country Code | DE | |
| Entity Tax Identification Number | 46-2159271 | |
| Entity Address, Address Line One | 222 Berkeley Street | |
| Entity Address, Address Line Two | 12th Floor | |
| Entity Address, City or Town | Boston | |
| Entity Address, State or Province | MA | |
| Entity Address, Postal Zip Code | 02116 | |
| City Area Code | 857 | |
| Local Phone Number | 264-4280 | |
| Title of 12(b) Security | Common Stock, $0.001 par value per share | |
| Trading Symbol | RYTM | |
| Security Exchange Name | NASDAQ | |
| Entity Current Reporting Status | Yes | |
| Entity Interactive Data Current | Yes | |
| Entity Filer Category | Large Accelerated Filer | |
| Entity Small Business | false | |
| Entity Emerging Growth Company | false | |
| Entity Shell Company | false | |
| Entity Common Stock, Shares Outstanding | 61,133,765 | |
| Current Fiscal Year End Date | --12-31 | |
| Document Fiscal Year Focus | 2024 | |
| Document Fiscal Period Focus | Q2 | |
| Entity Central Index Key | 0001649904 | |
| Amendment Flag | true | |
| Amendment Description | Amendment No. 1 |
| Insider Trading Arrangements | 3 Months Ended |
| Jun. 30, 2024 shares | |
| Trading Arrangements, by Individual | |
| Material Terms of Trading Arrangement | (c) Insider Trading Arrangements and Policies. On May 10, 2024, Pamela J. Cramer, the Company’s Chief Human Resources Officer, adopted until On May 13, 2024, Lynn Tetrault, a member of the Company’s board of directors, adopted until On May 22, 2024, Jennifer Good, a member of the Company’s board of directors, adopted until Other than as disclosed above, during the three months ended June 30, 2024, no director or “officer” (as defined in Rule 16a-1(f) under the Exchange Act) of the Company adopted or terminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408(a) of Regulation S-K. |
| Pamela J. Cramer | |
| Trading Arrangements, by Individual | |
| Name | Pamela J. Cramer |
| Title | Chief Human Resources Officer |
| Rule 10b5-1 Arrangement Adopted | true |
| Adoption Date | On May 10, 2024 |
| Rule 10b5-1 Arrangement Terminated | true |
| Termination Date | May 15, 2025 |
| Aggregate Available | 98,937 |
| Lynn Tetrault | |
| Trading Arrangements, by Individual | |
| Name | Lynn Tetrault |
| Title | board of directors |
| Rule 10b5-1 Arrangement Adopted | true |
| Adoption Date | May 13, 2024 |
| Rule 10b5-1 Arrangement Terminated | true |
| Termination Date | November 28, 2024 |
| Aggregate Available | 35,000 |
| Jennifer Good | |
| Trading Arrangements, by Individual | |
| Name | Jennifer Good |
| Title | board of directors |
| Rule 10b5-1 Arrangement Adopted | true |
| Adoption Date | May 22, 2024 |
| Rule 10b5-1 Arrangement Terminated | true |
| Termination Date | May 22, 2025 |
| Aggregate Available | 83,500 |
