XML 102 R64.htm IDEA: XBRL DOCUMENT
v3.23.4

Income Taxes - Changes in Valuation Allowance for Deferred Tax Assets (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2022 | Dec. 31, 2021
Income Tax Disclosure [Abstract] |  |
Valuation allowance at the beginning of the year | $ 16,332 | $ 2,414
Increases recorded to income tax provision | 21,778 | 13,918
Valuation allowance at the end of the year | $ 38,110 | $ 16,332

X
- Definition Valuation allowance increases recorded to income tax provision. + References No definition available. + Details
Name: | grph_ValuationAllowanceIncreasesRecordedToIncomeTaxProvision
Namespace Prefix: | grph_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-2 + Details
Name: | us-gaap_DeferredTaxAssetsValuationAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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