XML 46 R34.htm IDEA: XBRL DOCUMENT
v3.20.2

STOCKHOLDERS' EQUITY - PUBLIC OFFERING (Details) - USD ($) |  | 3 Months Ended | 9 Months Ended
--- | --- | --- | ---
May 27, 2020 | Sep. 30, 2020 | Sep. 30, 2020
Public Offering [Line Items] |  |  |
Proceeds from exercise of warrants |  |  | $ 16,000
Underwritten Public Offering |  |  |
Public Offering [Line Items] |  |  |
Issuance of common stock in connection with public offering | 107,049,375 |  |
Net proceeds from public offering after deducting underwriting discount and other offering expenses | $ 140,184,000 |  |
Combined public offering price per share of common stock and accompanying stock purchase warrants | $ 1.30 |  |
Proceeds from exercise of warrants |  |  | $ 16,000
Underwritten Public Offering | Stock Purchase Warrants |  |  |
Public Offering [Line Items] |  |  |
Warrants to purchase common stock, exercise price | $ 1.30 |  |
Warrants to purchase common stock, shares | 57,692,307 | 57,679,807 | 57,679,807
Warrants to purchase common stock exercised, shares |  | 12,500 |
Underwritten Public Offering | Pre-Funded Warrants |  |  |
Public Offering [Line Items] |  |  |
Warrants to purchase common stock, exercise price | $ 0.001 |  |
Warrants to purchase common stock, shares | 8,335,239 | 8,335,239 | 8,335,239
Combined public offering price per share of pre-funded warrants and accompanying stock purchase warrants | $ 1.299 |  |

X
- Definition Number of warrants exercised during the period + References No definition available. + Details
Name: | gern_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRightsExercised
Namespace Prefix: | gern_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public offering. + References No definition available. + Details
Name: | gern_PublicOfferingLineItems
Namespace Prefix: | gern_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of new shares of common stock issued during the period in connection with public offering. + References No definition available. + Details
Name: | gern_ShareOfCommonStockIssuedDuringPeriodSharesNewIssuesPublicOffering
Namespace Prefix: | gern_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Exercise price per share or per unit of warrants or rights outstanding. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644 + Details
Name: | us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644 + Details
Name: | us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The cash inflow from the issuance of common stock, preferred stock, treasury stock, stock options, and other types of equity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585 + Details
Name: | us-gaap_ProceedsFromIssuanceOrSaleOfEquity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The cash inflow associated with the amount received from holders exercising their stock warrants. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585 + Details
Name: | us-gaap_ProceedsFromWarrantExercises
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction. + References No definition available. + Details
Name: | us-gaap_SaleOfStockPricePerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Per share or per unit amount of equity securities issued. + References No definition available. + Details
Name: | us-gaap_SharesIssuedPricePerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=gern_UnderwrittenPublicOfferingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=gern_StockPurchaseWarrantsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=gern_PreFundedWarrantsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |