Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Oct. 30, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-36569
Entity Registrant Name	LANTHEUS HOLDINGS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	35-2318913
Entity Address, Address Line One	331 Treble Cove Road
Entity Address, Postal Zip Code	01862
Entity Address, City or Town	North Billerica,
Entity Address, State or Province	MA
City Area Code	(978)
Local Phone Number	671-8001
Title of 12(b) Security	Common stock, par value $0.01 per share
Trading Symbol	LNTH
Security Exchange Name	NASDAQ
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		66,871,355
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001521036
Current Fiscal Year End Date	--12-31