XML 50 R23.htm IDEA: XBRL DOCUMENT
v3.20.4

Commitments and Contingencies (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract] |
Schedule of Future Minimum Lease Payments | Future minimum lease payments under the Company’s non–cancelable operating leases as of December 31, 2020 were as follows (in thousands):
Year ended December 31: |  |  |  |
2021 |  | $ | 658 |
2022 |  |  | 403 |
2023 |  |  | 205 |
Total future minimum lease payments |  | $ | 1,266 |
Schedule of Expense under JHU Agreement | Expense under the JHU Agreement is as follows (in thousands):
|  | Year Ended December 31, |
|  | 2020 |  |  | 2019 |
Research and development |  | $ | 38 |  |  | $ | 194 |
General and administrative |  |  | 165 |  |  |  | 201 |
Total JHU Agreement expense |  | $ | 203 |  |  | $ | 395 |

X
- Definition Schedule of expense. + References No definition available. + Details
Name: | gray_ScheduleOfExpenseTableTextBlock
Namespace Prefix: | gray_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Tabular disclosure of future minimum payments required in the aggregate and for each of the five succeeding fiscal years for operating leases having initial or remaining noncancelable lease terms in excess of one year and the total minimum rentals to be received in the future under noncancelable subleases as of the balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=121573735&loc=d3e41502-112717 + Details
Name: | us-gaap_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration