Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Dec. 10, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Trading Symbol	AVIR
Entity Registrant Name	ATEA PHARMACEUTICALS, INC.
Entity Central Index Key	0001593899
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		82,616,937
Entity Current Reporting Status	No
Entity Shell Company	false
Entity File Number	001-39661
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-0574869
Entity Address, Address Line One	125 Summer Street
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02110
City Area Code	857
Local Phone Number	284-8891
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, $0.001 par value per share
Security Exchange Name	NASDAQ
Document Quarterly Report	true
Document Transition Report	false