Co-Development and License Agreements (License Arrangement [Member])	May 31, 2014 item
License Arrangement [Member]
Co-Development and License Agreements
Number of lead candidates	2
Number of lead candidates to be developed	1

Represents the number of lead candidates to be developed.

No definition available.

Name:	snta_NumberOfLeadCandidatesToBeDeveloped
Namespace Prefix:	snta_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant