Name:	knsa_DefinedContributionPlanEmployerMatchingContributionPercentOfMatchFirstThreePercent
Namespace Prefix:	knsa_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Percentage employer matches of the employee's percentage contribution matched for next 2% of each participant's salary contributed.

No definition available.

Name:	knsa_DefinedContributionPlanEmployerMatchingContributionPercentOfMatchNextTwoPercent
Namespace Prefix:	knsa_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of employees' gross pay for which the employer contributes a 50% matching contribution to a defined contribution plan.

No definition available.

Name:	knsa_DefinedContributionPlanEmployerMatchingFiftyPercentContributionPercentOfEmployeesGrossPay
Namespace Prefix:	knsa_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of employees' gross pay for which the employer contributes a 100% matching contribution to a defined contribution plan.

No definition available.

Name:	knsa_DefinedContributionPlanEmployerMatchingOneHundredPercentContributionPercentOfEmployeesGrossPay
Namespace Prefix:	knsa_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

Name:	us-gaap_CompensationAndRetirementDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of cost for defined contribution plan.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 70
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480794/715-70-50-1