XML 131 R58.htm IDEA: XBRL DOCUMENT
v3.22.1

Leases - Additional Information (Details) |  | 1 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Oct. 31, 2021 | Dec. 31, 2021 USD ($) ft² | Nov. 30, 2021 | Mar. 31, 2021 USD ($) ft² | Sep. 30, 2020 USD ($) ft² | Dec. 31, 2021 USD ($) ft² | Dec. 31, 2020 USD ($) | Dec. 31, 2018 ft²
Lessee Lease Description [Line Items] |  |  |  |  |  |  |  |
Operating leases cancelable and non-cancellable expiration dates |  |  |  |  |  | 2032 |  |
Operating leases Noncancelable expiration dates |  |  |  |  |  | 2026 |  |
Operating lease cost |  |  |  |  |  | $ 2,800,000 | $ 1,300,000 |
Variable lease costs |  |  |  |  |  | 429,000 | 355,000 |
Short-term lease costs |  |  |  |  |  | 119,000 | 96,000 |
Cash paid for operating leases |  |  |  |  |  | $ 1,100,000 | $ 989,000 |
Operating lease, weighted-average remaining lease term |  | 9 years 10 months 9 days |  |  |  | 9 years 10 months 9 days | 3 years 1 month 28 days |
Operating lease, weighted-average discount rate |  | 6.90% |  |  |  | 6.90% | 7.80% |
Gain on lease remeasurement |  |  |  |  |  | $ 539,000 |  |
Operating lease, aggregate monthly payments to lessor |  | $ 51,884,000 |  |  |  | 51,884,000 |  |
Letter of credit provided to lessor |  | $ 408,000 |  |  |  | 408,000 | $ 312,000 |
Other Income (Expense), Net |  |  |  |  |  |  |  |
Lessee Lease Description [Line Items] |  |  |  |  |  |  |  |
Gain on lease remeasurement |  |  |  |  |  | $ 539,000 |  |
2020 Lease |  |  |  |  |  |  |  |
Lessee Lease Description [Line Items] |  |  |  |  |  |  |  |
Office space leases | ft² |  |  |  |  | 59,407 |  |  |
Lease commencement month and year |  |  |  |  | 2021-08 |  |  |
Operating lease initial term |  |  |  |  | 10 years 6 months |  |  |
Operating lease, aggregate monthly payments to lessor |  |  |  |  | $ 39,500,000 |  |  |
Tenant improvement allowance |  |  |  |  | $ 13,400,000 |  |  |
Term for cancellation of lease |  |  |  |  | 84 months |  |  |
Notice period for cancellation of lease |  |  |  |  | 12 months |  |  |
Operating lease cancellation payment |  |  |  |  | $ 1,900,000 |  |  |
2020 Lease | Letter of Credit |  |  |  |  |  |  |  |
Lessee Lease Description [Line Items] |  |  |  |  |  |  |  |
Letter of credit provided to lessor |  |  |  |  | $ 312,000 |  |  |
Line of credit facility, expiration date |  |  |  |  | Oct. 31, 2031 |  |  |
2018 Lease |  |  |  |  |  |  |  |
Lessee Lease Description [Line Items] |  |  |  |  |  |  |  |
Office space leases | ft² |  |  |  |  |  |  |  | 16,153
Lease expiration date | May 31, 2024 |  | Apr. 30, 2022 |  |  |  |  |
First Amendment to 2020 Lease |  |  |  |  |  |  |  |
Lessee Lease Description [Line Items] |  |  |  |  |  |  |  |
Office space leases | ft² |  |  |  | 18,421 |  |  |  |
Operating lease, lease payments to lessor |  |  |  | $ 96,000 |  |  |  |
Tenant improvement allowance |  |  |  | $ 3,400,000 |  |  |  |
Term for cancellation of lease |  |  |  | 84 months |  |  |  |
Operating lease cancellation payment |  |  |  | $ 2,500,000 |  |  |  |
First Amendment to 2020 Lease | Letter of Credit |  |  |  |  |  |  |  |
Lessee Lease Description [Line Items] |  |  |  |  |  |  |  |
Letter of credit provided to lessor |  |  |  | $ 408,000 |  |  |  |
2021 Lease |  |  |  |  |  |  |  |
Lessee Lease Description [Line Items] |  |  |  |  |  |  |  |
Office space leases | ft² |  | 29,542 |  |  |  | 29,542 |  |
Lease commencement month and year |  | 2022-07 |  |  |  |  |  |
Operating lease initial term |  | 124 months |  |  |  | 124 months |  |
Operating lease option to extend |  |  |  |  |  | 5 years |  |
Operating lease existence of option to extend [true false] |  |  |  |  |  | true |  |
Operating lease, aggregate monthly payments to lessor |  | $ 34,400,000 |  |  |  | $ 34,400,000 |  |
Tenant improvement allowance |  | 8,200,000 |  |  |  |  |  |
2021 Lease | Other Assets |  |  |  |  |  |  |  |
Lessee Lease Description [Line Items] |  |  |  |  |  |  |  |
Security deposit paid |  | $ 874,000 |  |  |  | $ 874,000 |  |
California | 2018 Lease |  |  |  |  |  |  |  |
Lessee Lease Description [Line Items] |  |  |  |  |  |  |  |
Office space leases | ft² |  |  |  |  |  |  |  | 11,000

X
- Definition Building subject to ground leases. + References No definition available. + Details
Name: | eras_BuildingSubjectToGroundLeases
Namespace Prefix: | eras_
Data Type: | dtr-types:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition Gain on remeasurement of Operating Lease Assets and Liabilities. + References No definition available. + Details
Name: | eras_GainOnRemeasurementOfOperatingLeaseAssetsAndLiabilities
Namespace Prefix: | eras_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Lease commencement month and year. + References No definition available. + Details
Name: | eras_LeaseCommencementMonthAndYear
Namespace Prefix: | eras_
Data Type: | xbrli:gYearMonthItemType
Balance Type: | na
Period Type: | duration

X
- Definition Lessee operating lease monthly payments. + References No definition available. + Details
Name: | eras_LesseeOperatingLeaseMonthlyPayments
Namespace Prefix: | eras_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Notice period for cancellation of lease. + References No definition available. + Details
Name: | eras_NoticePeriodForCancellationOfLease
Namespace Prefix: | eras_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Operating lease cancellation payment. + References No definition available. + Details
Name: | eras_OperatingLeaseCancellationPayment
Namespace Prefix: | eras_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Operating leases cancelable and non-cancellable expiration dates. + References No definition available. + Details
Name: | eras_OperatingLeasesCancelableAndNonCancellableExpirationDates
Namespace Prefix: | eras_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | duration

X
- Definition Operating leases Noncancelable expiration dates. + References No definition available. + Details
Name: | eras_OperatingLeasesNonCancelableExpirationDates
Namespace Prefix: | eras_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tenant improvement allowance. + References No definition available. + Details
Name: | eras_TenantImprovementAllowance
Namespace Prefix: | eras_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Term for cancellation of lease. + References No definition available. + Details
Name: | eras_TermForCancellationOfLease
Namespace Prefix: | eras_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Date which lease or group of leases is set to expire, in YYYY-MM-DD format. + References No definition available. + Details
Name: | us-gaap_LeaseExpirationDate1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Indicates (true false) whether lessee has option to extend operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918673-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseExistenceOfOptionToExtend
Namespace Prefix: | us-gaap_
Data Type: | xbrli:booleanItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of lessee's undiscounted obligation for lease payment for operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918701-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Description of terms and conditions of option to extend lessee's operating lease. Includes, but is not limited to, information about option recognized as part of right-of-use asset and lease liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918673-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseOptionToExtend
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Term of lessee's operating lease, 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 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918673-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseTermOfContract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Definition Date the credit facility terminates, in YYYY-MM-DD format. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI http://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918686-209980 + Details
Name: | us-gaap_OperatingLeaseCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 5 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=123391704&loc=SL77918643-209977 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(1) -URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918686-209980 + Details
Name: | us-gaap_OperatingLeasePayments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Weighted average discount rate for operating lease calculated at point in time. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(4) -URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918686-209980 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI http://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971 + Details
Name: | us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI http://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(3) -URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918686-209980 + Details
Name: | us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of cash restricted as to withdrawal or usage, classified as noncurrent. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section 45 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=124098289&loc=d3e6812-107765 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(17)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=123431023&loc=SL98516268-108586 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 954 -SubTopic 210 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=120413173&loc=SL116631458-115580 + Details
Name: | us-gaap_RestrictedCashNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount of an asset, typically cash, provided to a counterparty to provide certain assurance of performance by the entity pursuant to the terms of a written or oral agreement, such as a lease. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.8,17) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_SecurityDeposit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of short-term lease cost, excluding expense for lease with term of one month or less. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918686-209980 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI http://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971 + Details
Name: | us-gaap_ShortTermLeaseCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of variable lease cost, excluded from lease liability, recognized when obligation for payment is incurred for finance and operating leases. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918686-209980 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI http://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971 + Details
Name: | us-gaap_VariableLeaseCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=us-gaap_OtherNonoperatingIncomeExpenseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=eras_TwoThousandTwentyLeaseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=eras_TwoThousandEighteenLeaseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=eras_FirstAmendmentToTwoThousandAndTwentyLeaseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=eras_TwoThousandTwentyOneLeaseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_OtherNoncurrentAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementGeographicalAxis=stpr_CA
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |