Cover Page - shares	6 Months Ended
	Jun. 30, 2023	Jul. 24, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2023
Document Transition Report	false
Entity File Number	001-39321
Entity Registrant Name	Avidity Biosciences, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-1336960
Entity Address, Address Line One	10578 Science Center Drive
Entity Address, Address Line Two	Suite 125
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92121
City Area Code	858
Local Phone Number	401-7900
Title of 12(b) Security	Common Stock, $0.0001 par value
Trading Symbol	RNA
Security Exchange Name	NASDAQ
Entity 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		74,096,207
Entity Central Index Key	0001599901
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q2
Amendment Flag	false