XML 81 R72.htm IDEA: XBRL DOCUMENT v3.20.4

Share-Based Compensation - Summary of non-vested stock option activities (Detail) - $ / shares		9 Months Ended
	Jan. 17, 2020	Sep. 30, 2020
Numbers of shares
Granted		72,000
2017 Plan [Member]
Numbers of shares
Number of shares Outstanding		9,812,881
Vested		(8,047,548)
Exercised		(115,888)
Forfeited	(332,566)	(336,377)
Surrendered		(332,566)
Number of shares Outstanding		980,502
Weighted average Grant date fair value
Weighted average grant date fair value Outstanding		$ 2.10
Vested		1.74
Exercised		2.14
Forfeited		$ 2.26
Surrendered		1.47
Weighted average grant date fair value Outstanding		$ 5.02
2018 Plan [Member]
Numbers of shares
Number of shares Outstanding		3,098,500
Vested		(2,273,500)
Number of shares Outstanding		825,000
Weighted average Grant date fair value
Weighted average grant date fair value Outstanding		$ 5.57
Vested		5.57
Weighted average grant date fair value Outstanding		$ 5.57
2019 Plan [Member]
Numbers of shares
Granted		72,000
Number of shares Outstanding		72,000
Weighted average Grant date fair value
Granted		$ 6.09
Weighted average grant date fair value Outstanding		$ 6.09
2020 Plan [Member]
Numbers of shares
Granted		1,068,733
Forfeited		(18,693)
Number of shares Outstanding		1,050,040
Weighted average Grant date fair value
Forfeited		$ 8.65
Granted		8.65
Weighted average grant date fair value Outstanding		$ 8.65

X

- Definition

Share based compensation by share based payment arrangement non vested options exercise in period number of shares.

+ References

No definition available.

+ Details

Name:	imab_ShareBasedCompensationByShareBasedPaymentArrangementNonVestedOptionsExerciseInPeriodNumberOfShares
Namespace Prefix:	imab_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Share Based Compensation By Share Based Payment Arrangement Non Vested Options Exercises In Period Weighted Average Grant Date Fair Value

+ References

No definition available.

+ Details

Name:	imab_ShareBasedCompensationByShareBasedPaymentArrangementNonVestedOptionsExercisesInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	imab_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsSurrendedNumberOfShares

+ References

No definition available.

+ Details

Name:	imab_Sharebasedcompensationarrangementbysharebasedpaymentawardoptionsnonvestedoptionssurrendednumberofshares
Namespace Prefix:	imab_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsSurrendedWeightedAverageGrantDateFairValue

+ References

No definition available.

+ Details

Name:	imab_Sharebasedcompensationarrangementbysharebasedpaymentawardoptionsnonvestedoptionssurrendedweightedaveragegrantdatefairvalue
Namespace Prefix:	imab_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Gross number of share options (or share units) granted during the period.

+ References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Number of non-vested options outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfShares
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

X

- Definition

Number of non-vested options forfeited.

+ References

No definition available.

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedNumberOfShares
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Weighted average grant-date fair value of non-vested options forfeited.

+ References

No definition available.

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedOptionsForfeitedWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Weighted average grant-date fair value of non-vested options outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

X

- References

No definition available.

+ Details

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

X

- Definition

Number of options vested.

+ References

No definition available.

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Weighted average grant-date fair value of options vested.

+ References

No definition available.

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_PlanNameAxis=imab_TwentySeventeenEmployeeStockOptionPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PlanNameAxis=imab_TwentyEighteenEmployeeStockOptionPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PlanNameAxis=imab_TwentyNineteenEmployeeStockOptionPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PlanNameAxis=imab_ShareIncentivePlanTwoThousandTwentyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: