No definition available.

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- Definition

Description of the frequency of periodic stock vesting, which may be presented in a variety of ways (for example, monthly, quarterly, annually).

+ References

No definition available.

+ Details

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- References

No definition available.

+ Details

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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

+ Details

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Period Type:	duration

- Definition

Gross number of share options (or share units) granted during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(01)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

+ References

+ Details

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Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of vesting of award under share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

+ Details

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- Details

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- Details

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Name:	us-gaap_AwardTypeAxis=erna_NonQualifiedStockOptionMember
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STOCK-BASED COMPENSATION, Stock Option Activity (Details) - $ / shares			3 Months Ended
	Apr. 26, 2024	Jan. 01, 2024	Mar. 31, 2024	Mar. 31, 2023
Stock Options [Member]
Stock-based Compensation [Abstract]
Stock options granted (in shares)			1,874,000	212,000
CEO Inducement Grant [Abstract]
Stock options granted (in shares)			1,874,000	212,000
Stock Options [Member] \| Sanjeev Luther [Member] \| Subsequent Event [Member]
CEO Inducement Grant [Abstract]
Vesting period	3 years
Frequency of stock vesting installments	monthly
Stock Options [Member] \| Sanjeev Luther [Member] \| Vesting on First Anniversary [Member] \| Subsequent Event [Member]
CEO Inducement Grant [Abstract]
Vesting percentage	25.00%
Stock Options [Member] \| Sanjeev Luther [Member] \| Vesting on Remaining Years [Member] \| Subsequent Event [Member]
CEO Inducement Grant [Abstract]
Vesting period	2 years
Vesting percentage	75.00%
Nonqualified Stock Options [Member] \| Sanjeev Luther [Member]
Stock-based Compensation [Abstract]
Stock options granted (in shares)		1,685,000
CEO Inducement Grant [Abstract]
Stock options granted (in shares)		1,685,000
Exercise price (in dollars per share)		$ 1.8
Vesting period		4 years
Frequency of stock vesting installments			monthly
Nonqualified Stock Options [Member] \| Sanjeev Luther [Member] \| Vesting on First Anniversary [Member]
CEO Inducement Grant [Abstract]
Vesting percentage		25.00%
Nonqualified Stock Options [Member] \| Sanjeev Luther [Member] \| Vesting on Remaining Years [Member]
CEO Inducement Grant [Abstract]
Vesting period		3 years
Vesting percentage		75.00%