Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Feb. 21, 2020	Jun. 30, 2019
Cover page.
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	001-35726
Entity Registrant Name	Radius Health, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	80-0145732
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
City Area Code	617
Local Phone Number	551-4000
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	RDUS
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Public Float			$ 1.3
Entity Common Stock, Shares Outstanding		46,217,719
Documents Incorporated by Reference	Portions of the registrant’s definitive Proxy Statement for its 2020 Annual Meeting of Stockholders are incorporated by reference into Part III of this Annual Report on Form 10-K.
Entity Central Index Key	0001428522
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY