Cover Page - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Mar. 04, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-35342
Entity Registrant Name	LUMOS PHARMA, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	42-1491350
Entity Address, Address Line One	4200 Marathon Blvd #200
Entity Address, City or Town	Austin
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	78756
City Area Code	512
Local Phone Number	215-2630
Title of 12(b) Security	Common Stock
Trading Symbol	LUMO
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 63.2
Entity Common Stock, Shares Outstanding (in shares)		8,358,625
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement for its 2022 Annual Meeting of Shareholders, to be held on May 4, 2022, which will be filed within 120 days of December 31, 2021, are incorporated by reference into Part III of this Annual Report on Form 10-K.
Entity Central Index Key	0001126234
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false