Summary of Significant Accounting Policies - Additional Information (Details)	Jan. 01, 2026
Maximum [Member]
Significant Accounting Policies [Line Items]
Performance award Percentage	200.00%
Minimum [Member]
Significant Accounting Policies [Line Items]
Performance award Percentage	0.00%

Share Based Compensation Arrangement By Share Based Payment Award Performance Award Percentage

No definition available.

Name:	kymr_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformanceAwardPercentage
Namespace Prefix:	kymr_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration