Commitments and contingencies - Licenses (Details) $ in Millions	6 Months Ended
Jun. 30, 2025 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Maximum eligible development and commercial milestone payments	$ 122.0

Amount of maximum aggregate development and commercial milestone payments eligible to receive.

No definition available.

Name:	sgmt_MaximumAggregateDevelopmentAndCommercialMilestonePaymentsEligibleToReceive
Namespace Prefix:	sgmt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration