Amendment fees payment.

No definition available.

Name:	eigr_AmendmentFeesPayment
Namespace Prefix:	eigr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Debt instrument covenant noncompliance penalty.

+ References

No definition available.

+ Details

Name:	eigr_DebtInstrumentCovenantNoncompliancePenalty
Namespace Prefix:	eigr_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument exit fee payable percentage.

+ References

No definition available.

+ Details

Name:	eigr_DebtInstrumentExitFeePayablePercentage
Namespace Prefix:	eigr_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt instrument fee enforceable maximum period from funding.

+ References

No definition available.

+ Details

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

- Definition

Debt instrument interest payment period.

+ References

No definition available.

+ Details

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

- Definition

Debt instrument prepayment fee percentage.

+ References

No definition available.

+ Details

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Namespace Prefix:	eigr_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument principal and interest payment period.

+ References

No definition available.

+ Details

Name:	eigr_DebtInstrumentPrincipalAndInterestPaymentPeriod
Namespace Prefix:	eigr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument success fees payable maximum period after approval.

+ References

No definition available.

+ Details

Name:	eigr_DebtInstrumentSuccessFeesPayableMaximumPeriodAfterApproval
Namespace Prefix:	eigr_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument success fees payable percentage.

+ References

No definition available.

+ Details

Name:	eigr_DebtInstrumentSuccessFeesPayablePercentage
Namespace Prefix:	eigr_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument unamortized additional exit fees.

+ References

No definition available.

+ Details

Name:	eigr_DebtInstrumentUnamortizedAdditionalExitFees
Namespace Prefix:	eigr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Debt instrument unamortized exit fees.

+ References

No definition available.

+ Details

Name:	eigr_DebtInstrumentUnamortizedExitFees
Namespace Prefix:	eigr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Prepayment of loan fee description.

+ References

No definition available.

+ Details

Name:	eigr_PrepaymentOfLoanFeeDescription
Namespace Prefix:	eigr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Repayments of loan agreement exit fee.

+ References

No definition available.

+ Details

Name:	eigr_RepaymentsOfLoanAgreementExitFee
Namespace Prefix:	eigr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

States whether the entity was in compliance with the debt covenants throughout the reporting period, and describes facts and circumstances of any compliance failure.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (g)
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Description of minimum financial levels (for example, tangible net worth and working capital) and achievement of certain financial ratios (for example, working capital ratio and debt service coverage ratio), and adherence to certain clauses which generally require or restrict certain actions (for example, entering into a debt arrangement with equal or greater seniority, and selling or discontinuing a certain business segment or material subsidiary) to be in compliance with the covenant clauses of the debt agreement. May also include a discussion of the adverse consequences that would result if the entity violates or fails to satisfy the covenants.

+ References

+ Details

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

- Definition

Description of reference rate used for variable rate of debt instrument.

+ References

No definition available.

+ Details

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

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (a)
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-Section 45
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

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

- Definition

Date when the debt instrument is scheduled to be fully repaid, in YYYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Topic 210
-SubTopic 10
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-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
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-Paragraph 14
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-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

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

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=eigr_TrancheAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

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Data Type:	na
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- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=eigr_LoanPrepaidDuringFirstTwelveMonthsMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=eigr_LoanPrepaidDuringThirteenToTwentyFourMonthsMember
Namespace Prefix:
Data Type:	na
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Name:	srt_RangeAxis=srt_MinimumMember
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Name:	us-gaap_RegulatoryAgencyAxis=eigr_FoodAndDrugAdministrationMember
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Debt - Additional Information (Detail) - USD ($) $ in Thousands				1 Months Ended	3 Months Ended
	Oct. 06, 2021	Feb. 23, 2021	Mar. 05, 2019	Dec. 31, 2016	Mar. 31, 2022	Dec. 31, 2021	Aug. 03, 2018	May 31, 2018
Debt Instrument [Line Items]
Face value of term loan					$ 30,000	$ 30,000
Loan final repayment exit fees payable					$ (3,277)	$ (3,277)
Loan agreement, covenant noncompliance penalty					5.00%
Loan agreement, covenant description					The loan includes customary events of default, including failure to pay amounts due, breaches of covenants and warranties, material adverse effect events, certain cross defaults and judgments, and insolvency
Loan agreement, covenant compliance					and accelerate the maturity of the debt.
Oxford Loan [Member]
Debt Instrument [Line Items]
Loan agreement, aggregate borrowing capacity				$ 25,000
Loan, maturity period				Jul. 01, 2021
Repayments of loan agreement exit fee					$ 900
Oxford Loan [Member] \| Tranche A [Member]
Debt Instrument [Line Items]
Face value of term loan				$ 15,000
Amendment [Member] \| Tranche B [Member]
Debt Instrument [Line Items]
Face value of term loan								$ 5,000
Amendment [Member] \| Tranche C [Member]
Debt Instrument [Line Items]
Face value of term loan							$ 5,000
Amended Oxford Loan [Member]
Debt Instrument [Line Items]
Loan agreement, aggregate borrowing capacity			$ 35,000
Loan, maturity period					Mar. 01, 2024
Loan outstanding			23,300
Borrowings from loan agreement			6,700
Loan agreement, floating rate terms					floating rate per annum equal to the greater of either the 30-day U.S. Dollar LIBOR reported in the Wall Street Journal plus 6.64% or 9.15%
Percentage of exit fee on principal balance					7.50%
Loan final repayment exit fees payable					$ 2,300
Loan final repayment additional exit fees payable					$ 1,000
Prepayment of loan fee, description					calculated as of the loan origination date, equal to (i) 2.0% of the loan prepaid during the first 12 months and (ii) 1.0% of the loan prepaid in months 13-24.
Amended Oxford Loan [Member] \| Loan Prepaid During First 12 Months [Member]
Debt Instrument [Line Items]
Debt instrument prepayment fee percentage					2.00%
Amended Oxford Loan [Member] \| Loan Prepaid During 13 to 24 Months [Member]
Debt Instrument [Line Items]
Debt instrument prepayment fee percentage					1.00%
Amended Oxford Loan [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Loan agreement, interest rate	9.15%
Amended Oxford Loan [Member] \| Food and Drug Administration [Member]
Debt Instrument [Line Items]
Percentage of success fee					5.00%
Success fees payable maximum period after approval					30 days
Amended Oxford Loan [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Loan agreement, percentage to be added to the interest rate under condition	6.64%
Amended Oxford Loan [Member] \| Amended Tranche A [Member]
Debt Instrument [Line Items]
Loan agreement, aggregate borrowing capacity			30,000
Amended Oxford Loan [Member] \| Amended Tranche A [Member] \| Food and Drug Administration [Member]
Debt Instrument [Line Items]
Fee payable maximum period from funding					10 years
Amended Oxford Loan [Member] \| Amended Tranche B [Member]
Debt Instrument [Line Items]
Loan agreement, remaining borrowing capacity			$ 5,000
Fifth Amended Oxford Loan [Member]
Debt Instrument [Line Items]
Principal and interest payment period		19 years
Interest payment period		17 months
Amendment fees payment		$ 200
Fifth Amended Oxford Loan [Member] \| Tranche B [Member]
Debt Instrument [Line Items]
Principal and interest payment period		13 years
Interest payment period		6 months