| Document and Entity Information | Dec. 30, 2020 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | RADIUS HEALTH, INC. |
| Document Type | 8-K |
| Amendment Flag | false |
| Entity Central Index Key | 0001428522 |
| Document Period End Date | Dec. 30, 2020 |
| Entity Emerging Growth Company | false |
| Entity File Number | 001-35726 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 80-0145732 |
| Entity Address, Address Line One | 22 Boston Wharf Road |
| Entity Address, Address Line Two | 7th Floor |
| Entity Address, City or Town | Boston |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02210 |
| City Area Code | 617 |
| Local Phone Number | 551-4000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, $0.0001 par value per share |
| Trading Symbol | RDUS |
| Security Exchange Name | NASDAQ |
| Former Address | |
| Document And Entity Information [Line Items] | |
| Entity Address, Address Line One | 950 Winter Street |
| Entity Address, City or Town | Waltham |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02451 |
