Common Stock - Schedule of Outstanding Warrant Activity (Details)	3 Months Ended
Mar. 31, 2026 shares
Shortfall Warrants [Member]
Schedule of Outstanding Warrant Activity [Line Items]
Balance	1,135,499
Issued
Balance	1,135,499
Publicly Traded Warrants [Member]
Schedule of Outstanding Warrant Activity [Line Items]
Balance	14,166,666
Issued
Balance	14,166,666
Term Loan Warrants [Member]
Schedule of Outstanding Warrant Activity [Line Items]
Balance	3,500,000
Issued
Balance	3,500,000
September 2025 Offering Warrants [Member]
Schedule of Outstanding Warrant Activity [Line Items]
Balance	5,868,336
Issued
Balance	5,868,336
October 2025 Offering Warrants [Member]
Schedule of Outstanding Warrant Activity [Line Items]
Balance	9,248,136
Issued
Balance	9,248,136
Issued Pre-Funded Warrants [Member]
Schedule of Outstanding Warrant Activity [Line Items]
Balance
Issued	27,053,850
Balance	27,053,850
Series A Warrants & February 2026 Placement Agent Warrants [Member]
Schedule of Outstanding Warrant Activity [Line Items]
Balance
Issued	123,750,000
Balance	123,750,000

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-3

+ Details

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

- Definition

Net number of non-option equity instruments granted to participants.

+ References

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

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=coch_ShortfallWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=coch_PubliclyTradedWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=coch_TermLoanWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=coch_September2025OfferingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=coch_October2025OfferingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=coch_IssuedPreFundedWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ClassOfWarrantOrRightAxis=coch_SeriesAWarrantsFebruaryTwoThousandTwentySixPlacementAgentWarrantsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: