Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Fair value assets, level 2 to level 3 transfers, amount	$ 0	$ 0

Fair value assets level 2 to Level 3 transfers amount.

No definition available.

Name:	kymr_FairValueAssetsLevel2ToLevel3TransfersAmount
Namespace Prefix:	kymr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant