Fair Value of Financial Assets and Liabilities - Additional Information (Detail) - USD ($)	12 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Transfers between Level 1, Level 2 and Level 3	$ 0	$ 0	$ 0

Amount of transfers of financial instruments classified as an asset or liability between level 1, level 2, and level 3 of the fair value hierarchy.

No definition available.

Name:	enta_FairValueMeasurementsInterTransfersBetweenLevels
Namespace Prefix:	enta_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration