It is initial cash investment.

No definition available.

Name:	casi_InitialCashInvestment
Namespace Prefix:	casi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represent the Investment amount committed by company.

+ References

No definition available.

+ Details

Name:	casi_InvestmentCommitment
Namespace Prefix:	casi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the committed amount of cash payment within three years from the date of establishment of CASI Wuxi.

+ References

No definition available.

+ Details

Name:	casi_PaymentsToBePaidWithinThreeYears
Namespace Prefix:	casi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represent the selected and as to be transferred.

+ References

No definition available.

+ Details

Name:	casi_SelectedAndasToBeTransferred
Namespace Prefix:	casi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

The cash outflow associated with the purchase of all investments (debt, security, other) during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_BusinessAcquisitionAxis=casi_CASIWuxiMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OptionIndexedToIssuersEquityTypeAxis=us-gaap_CallOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Redeemable Noncontrolling Interest - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended
	May 31, 2019	Mar. 31, 2019	Sep. 30, 2020	Feb. 28, 2019	Dec. 26, 2018
Noncontrolling Interest [Line Items]
Value of transfer of selected ANDAs			$ 30
CASI Wuxi [Member]
Noncontrolling Interest [Line Items]
Equity Method Investment, Ownership Percentage					80.00%
Investment Commitment					$ 80
Initial Cash Investment				$ 21
Value of transfer of selected ANDAs	$ 30
Payments To Be Paid Within Three Years			$ 29
Payments to Acquire Investments		$ 20
CASI Wuxi [Member] \| Call Option [Member]
Noncontrolling Interest [Line Items]
Equity Method Investment, Ownership Percentage			20.00%