XML 54 R42.htm IDEA: XBRL DOCUMENT
v3.21.2

Leases - Additional Information (Details) $ in Millions | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2021 USD ($) ft² | Sep. 30, 2020 USD ($) | Sep. 30, 2021 USD ($) ft² | Sep. 30, 2020 USD ($) | May 31, 2021 ft²
Lessee, Lease, Description [Line Items] |  |  |  |  |
Operating lease cost | $ 2.4 | $ 2.9 | $ 7.1 | $ 8.3 |
Variable lease cost | 1.4 | $ 0.5 | $ 3.7 | $ 1.5 |
Non-related Party [Member] |  |  |  |  |
Lessee, Lease, Description [Line Items] |  |  |  |  |
Rentable area | ft² |  |  |  |  | 11,000
Monthly fixed rental payment proceeds | $ 0.1 |  |  |  |
Sonoma [Member] |  |  |  |  |
Lessee, Lease, Description [Line Items] |  |  |  |  |
Rentable area | ft² | 18,000 |  | 18,000 |  |
Monthly fixed rental payment proceeds | $ 0.1 |  |  |  |
Tenant improvements | $ 4.6 |  | $ 4.6 |  |

X
- Definition Monthly fixed rental payment proceeds. + References No definition available. + Details
Name: | lyel_MonthlyFixedRentalPaymentProceeds
Namespace Prefix: | lyel_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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 Net rentable area for properties owned. + References No definition available. + Details
Name: | us-gaap_NetRentableArea
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:areaItemType
Balance Type: | na
Period Type: | instant

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 Carrying amount as of the balance sheet date of improvements having a life longer than one year that were made for the benefit of one or more tenants. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(f)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 + Details
Name: | us-gaap_TenantImprovements
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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: | dei_LegalEntityAxis=lyel_NonRelatedPartyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=lyel_SonomaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |