The amount agreed to waive payment as per waiver agreement.

No definition available.

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Namespace Prefix:	erna_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of deposit paid which will be applied to the last month of the first work order.

+ References

No definition available.

+ Details

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Namespace Prefix:	erna_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount agreed to pay an initial fee under Master Services Agreement (or "MSA").

+ References

No definition available.

+ Details

Name:	erna_MasterServiceAgreementInitialFeesPayable
Namespace Prefix:	erna_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The monthly master service agreement ("MSA") fees payable to related party.

+ References

No definition available.

+ Details

Name:	erna_MonthlyMasterServicesAgreementFeesPayable
Namespace Prefix:	erna_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The Company may terminate the first work under the MSA on or after the second anniversary of the date of the MSA, subject to providing Factor with prior notice, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Namespace Prefix:	erna_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The Master Services Agreement (or "MSA") contains customary confidentiality provisions and representations and warranties of the parties, and the Master Services Agreement (or "MSA") may be terminated by ether party prior notice, subject to any superseding termination provisions contained in a particular work order, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	erna_NoticePeriodForSupersedingTerminationProvisions
Namespace Prefix:	erna_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of equal monthly installments for initial fees payable.

+ References

No definition available.

+ Details

Name:	erna_NumberOfMonthlyInstallmentsForFeesPayable
Namespace Prefix:	erna_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount reimburse for costs already incurred or paid.

+ References

No definition available.

+ Details

Name:	erna_ReimburseCostsIncurredOrPaid
Namespace Prefix:	erna_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of required periodic fees payment.

+ References

No definition available.

+ Details

Name:	erna_RelatedPartyTransactionPeriodicFeesPaymentAmount
Namespace Prefix:	erna_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_RelatedPartyTransactionDueFromToRelatedPartyAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The costs incurred in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, excluding in-process research and development acquired in a business combination consummated during the period. Excludes software research and development, which has a separate concept.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 730
-SubTopic 10
-Section 50
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=6420194&loc=d3e21568-108373

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=erna_FactorBioscienceIncMember
Namespace Prefix:
Data Type:	na
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- Details

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RELATED PARTY TRANSACTIONS (Details) $ in Thousands		1 Months Ended	3 Months Ended		9 Months Ended
RELATED PARTY TRANSACTIONS (Details) $ in Thousands	Sep. 09, 2022 USD ($) Installment	Oct. 31, 2022 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)
Related Party Transaction [Abstract]
Research and development expense			$ 4,963	$ 1,491	$ 8,430	$ 8,456
Factor Bioscience Inc. [Member]
Related Party Transaction [Abstract]
Agreed waive payment	$ 3,500
Master services agreement, initial fees payable	$ 5,000
Number of monthly installments for fees payable \| Installment	12
Monthly installment fees amount	$ 400
Monthly master services agreement fees payable initial 12-month	400
Deposit paid to be applied to last month of first work order	$ 400
Notice period for first termination of contract					120 days
Notice period for superseding termination provisions					30 days
Research and development expense			$ 3,500
Factor Bioscience Inc. [Member] \| Subsequent Event [Member]
Related Party Transaction [Abstract]
Reimburse costs incurred or paid		$ 100