v3.23.3

Leases - Additional Information (Details) - USD ($) | 1 Months Ended |
--- | --- | ---
Aug. 31, 2023 | Sep. 30, 2023
Leases [Abstract] |  |
Lease not yet commence, term of contract | 24 months |
Monthly sublease base rent | $ 100,000 |
Lessee, operating lease, lease not yet commenced, future lease payments | $ 2,600,000 |
Lessee, Operating Lease, Lease Not yet Commenced, Existence of Option to Extend [true false] | true |
Lessee, operating lease, lease not yet commenced, option to extend | The Company has the option to extend the sublease through September 30, 2029. |
Lessee, operating lease, lease not yet commenced, operating lease right-of-use asset |  | $ 0
Lessee, operating lease, lease not yet commenced, operating lease liability |  | $ 0

X
- Definition Lessee, operating lease, lease not yet commenced, lease liability. + References No definition available. + Details
Name: | asmb_LesseeOperatingLeaseLeaseNotYetCommencedLeaseLiability
Namespace Prefix: | asmb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Lessee, operating lease, lease not yet commenced, payments due. + References No definition available. + Details
Name: | asmb_LesseeOperatingLeaseLeaseNotYetCommencedPaymentsDue
Namespace Prefix: | asmb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Lessee, operating lease, lease not yet commenced, right-of-use asset. + References No definition available. + Details
Name: | asmb_LesseeOperatingLeaseLeaseNotYetCommencedRightOfUseAsset
Namespace Prefix: | asmb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Monthly sublease base rent. + References No definition available. + Details
Name: | asmb_MonthlySubleaseBaseRent
Namespace Prefix: | asmb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Definition Indicates (true false) whether lessee has option to extend operating lease not yet commenced. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147478964/842-20-50-3 + Details
Name: | us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedExistenceOfOptionToExtend
Namespace Prefix: | us-gaap_
Data Type: | xbrli:booleanItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description of terms and conditions of option to extend lessee's operating lease that has not yet commenced. Includes, but is not limited to, information about option recognized as part of right-of-use asset and lease liability. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147478964/842-20-50-3 + Details
Name: | us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedOptionToExtend
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Term of lessee's operating lease not yet commenced, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147478964/842-20-50-3 + Details
Name: | us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant