XML 59 R48.htm IDEA: XBRL DOCUMENT
v3.23.1

WARRANTS, Warrants Outstanding Issued (Details) | 3 Months Ended
--- | ---
Mar. 31, 2023 $ / shares shares
Warrants Outstanding [Abstract] |
Warrants outstanding (in shares) | shares | 4,713
March 2022 PIPE [Member] |
Warrants Outstanding [Abstract] |
Warrants outstanding (in shares) | shares | 343
Exercise price (in dollars per share) | $ / shares | $ 38.2
Date exercisable | Sep. 09, 2022
Expiration date | Sep. 09, 2027
November 2022 PIPE [Member] |
Warrants Outstanding [Abstract] |
Warrants outstanding (in shares) | shares | 4,370
Exercise price (in dollars per share) | $ / shares | $ 3.28
Date exercisable | Jun. 02, 2023
Expiration date | Jun. 02, 2028
Warrant [Member] |
Warrants Outstanding [Abstract] |
Exercise price (in dollars per share) | $ / shares | $ 5.82
Warrants outstanding weighted average contractual life | 5 years 1 month 13 days

X
- Definition Date the warrants or rights are to expire, in YYYY-MM-DD format. + References No definition available. + Details
Name: | erna_ClassOfWarrantOrRightExpirationDate
Namespace Prefix: | erna_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Date the warrants or rights are exercisable, in YYYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI https://asc.fasb.org/extlink&oid=126973232&loc=d3e21475-112644 + Details
Name: | us-gaap_ClassOfWarrantOrRighstDateFromWhichWarrantsOrRightsExercisable
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Exercise price per share or per unit of warrants or rights outstanding. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI https://asc.fasb.org/extlink&oid=126973232&loc=d3e21475-112644 + Details
Name: | us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of warrants or rights outstanding. + References No definition available. + Details
Name: | us-gaap_ClassOfWarrantOrRightOutstanding
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_WarrantsAndRightsNoteDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period between issuance and expiration of outstanding warrant and right embodying unconditional obligation requiring redemption by transferring asset at specified or determinable date or upon event certain to occur, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258 + Details
Name: | us-gaap_WarrantsAndRightsOutstandingTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_ClassOfWarrantOrRightAxis=erna_March2022WarrantsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ClassOfWarrantOrRightAxis=erna_November2022WarrantsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ClassOfWarrantOrRightAxis=us-gaap_WarrantMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |