Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2022	Oct. 31, 2022
Document information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2022
Entity File Number	001-38492
Entity Registrant Name	Kiniksa Pharmaceuticals, Ltd.
Entity Incorporation, State or Country Code	D0
Entity Tax Identification Number	98-1327726
Entity Address, Address Line One	Clarendon House
Entity Address, Address Line Two	2 Church Street
Entity Address, City or Town	Hamilton
Entity Address, Country	BM
Entity Address, Postal Zip Code	HM11
City Area Code	808
Local Phone Number	451-3453
Title of 12(b) Security	Class A Common Shares
Trading Symbol	KNSA
Security Exchange Name	NASDAQ
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
Entity Shell Company	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001730430
Amendment Flag	false
Common Shares
Document information
Entity Common Stock, Shares Outstanding		69,531,762
Class A common shares
Document information
Entity Common Stock, Shares Outstanding		34,531,084
Class B common shares
Document information
Entity Common Stock, Shares Outstanding		1,813,457
Class A1 common shares
Document information
Entity Common Stock, Shares Outstanding		17,129,603
Class B1 common shares
Document information
Entity Common Stock, Shares Outstanding		16,057,618