| Document and Entity Information | Dec. 09, 2020 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001521036 |
| Document Type | 8-K |
| Document Period End Date | Dec. 9, 2020 |
| Entity Registrant Name | LANTHEUS HOLDINGS, INC. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-36569 |
| Entity Tax Identification Number | 35-2318913 |
| Entity Address, Address Line One | 331 Treble Cove Road |
| Entity Address, City or Town | North Billerica |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 01862 |
| City Area Code | (978) |
| Local Phone Number | 671-8001 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common stock, par value $0.01 per share |
| Trading Symbol | LNTH |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
