v3.23.3

Sale of Common Stock - Additional Information (Details) - 2020 At the Market Offerings - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Aug. 31, 2020
Subsidiary Sale Of Stock [Line Items]
Initial public offering value of shares authorized					$ 100.0
Number of shares sold	0	0	3,134,045	0
Net proceeds from the issuance of common stock through equity plans			$ 4.5

X

- Definition

The value of common stock authorized to issue in a public offering.

+ References

No definition available.

+ Details

Name:	asmb_InitialPublicOfferingValueOfSharesAuthorized
Namespace Prefix:	asmb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

The cash inflow associated with the amount received from entity's first offering of stock to the public.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 14
-Subparagraph (a)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-14

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

+ References

No definition available.

+ Details

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

X

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

X

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=asmb_TwoThousandAndTwentyAtTheMarketOfferingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: