XML 34 R21.htm IDEA: XBRL DOCUMENT v3.10.0.1

FAIR VALUE MEASUREMENTS - SECURITIES WITH UNREALIZED LOSSES (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Available for sale securities with unrealized losses
Less Than 12 Months - Estimated Fair Value	$ 92,792	$ 77,168
Less Than 12 Months - Gross Unrealized Losses	(137)	(169)
12 Months or Longer - Estimated Fair Value	15,482	13,959
12 Months or Longer - Gross Unrealized Losses	(39)	(42)
Total - Estimated Fair Value	108,274	91,127
Total - Gross Unrealized Losses	(176)	(211)
Commercial paper (due in less than one year)
Available for sale securities with unrealized losses
Less Than 12 Months - Estimated Fair Value	14,773	7,717
Less Than 12 Months - Gross Unrealized Losses	(22)	(1)
Total - Estimated Fair Value	14,773	7,717
Total - Gross Unrealized Losses	(22)	(1)
Corporate notes (due in less than one year)
Available for sale securities with unrealized losses
Less Than 12 Months - Estimated Fair Value	59,876	55,210
Less Than 12 Months - Gross Unrealized Losses	(82)	(106)
12 Months or Longer - Estimated Fair Value	15,482	1,499
12 Months or Longer - Gross Unrealized Losses	(39)	(2)
Total - Estimated Fair Value	75,358	56,709
Total - Gross Unrealized Losses	(121)	(108)
Corporate notes (due in one to two years)
Available for sale securities with unrealized losses
Less Than 12 Months - Estimated Fair Value	18,143	14,241
Less Than 12 Months - Gross Unrealized Losses	(33)	(62)
Total - Estimated Fair Value	18,143	14,241
Total - Gross Unrealized Losses	$ (33)	(62)
Government-sponsored enterprise securities (due in less than one year)
Available for sale securities with unrealized losses
12 Months or Longer - Estimated Fair Value		12,460
12 Months or Longer - Gross Unrealized Losses		(40)
Total - Estimated Fair Value		12,460
Total - Gross Unrealized Losses		$ (40)

X

- References

No definition available.

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27337-111563

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=gern_CommercialPaperDueInLessThanOneYearMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=gern_CorporateNoteSecuritiesDueInLessThanOneYearMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=gern_CorporateNoteSecuritiesDueInOneToTwoYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=gern_USGovernmentSponsoredEnterprisesDebtSecuritiesDueInLessThanOneYearMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: