v3.23.3

Subsequent Event - Additional Information (Details) - Subsequent Event - Gilead Sciences, Inc. | Oct. 15, 2023 USD ($) Timepoint Program Director $ / shares shares
--- | ---
Option, License and Collaboration Agreement |
Subsequent Event [Line Items] |
Collaboration term | 12 years
Proceeds received in collaboration agreement | $ 100,000,000
Upfront cash payment received | $ 84,800,000
Number of timepoints of program | Timepoint | 2
Percentage cover of research and development costs | 40.00%
Percentage share of profits and operating loss for products | 40.00%
Number of fellow-contributed programs | Program | 2
Option, License and Collaboration Agreement | Minimum |
Subsequent Event [Line Items] |
Threshold payment of opt-in fee | $ 45,000,000
Option, License and Collaboration Agreement | Maximum |
Subsequent Event [Line Items] |
Threshold payment of opt-in fee | 125,000,000
Option, License and Collaboration Agreement | Regulatory and Commercial Milestones | Maximum |
Subsequent Event [Line Items] |
Potential milestone payments | 330,000,000
Gilead Equity Agreements | Common Stock |
Subsequent Event [Line Items] |
Upfront equity investment | $ 15,200,000
Number of shares sold | shares | 13,073,668
Sale of stock, price per share | $ / shares | $ 1.16
Expected equity financing completion date | Jul. 15, 2024
Percentage of then-outstanding voting capital stock subject to stockholder approval | 29.90%
Purchase price per share of additional shares description | The purchase price per share for additional shares purchased by Gilead will be equal to the lesser of a 35% premium to the 30-day volume weighted average price immediately prior to the date of purchase or a 35% premium to the 30-day volume weighted average price immediately prior to delivery by Gilead of notice of the anticipated closing date.
Number of days volume considered for weighted average price to calculate premium | 30 days
Number of years of standstill and lockup provisions | 3 years
Number of directors, right to designate in company board | Director | 2
Gilead Equity Agreements | Common Stock | Minimum |
Subsequent Event [Line Items] |
Potential proceeds from equity financing | $ 30,000,000
Gilead Equity Agreements | Common Stock | Maximum |
Subsequent Event [Line Items] |
Percentage of premium to weighted average price immediately prior to date of purchase | 35.00%
Percentage of premium to weighted average price immediately prior to delivery of notice of closing date | 35.00%
Third Year of Collaboration Agreement |
Subsequent Event [Line Items] |
Potential proceeds from collaboration extension fees | $ 75,000,000
Fifth Year of Collaboration Agreement |
Subsequent Event [Line Items] |
Potential proceeds from collaboration extension fees | 75,000,000
Seventh Year of Collaboration Agreement |
Subsequent Event [Line Items] |
Potential proceeds from collaboration extension fees | $ 75,000,000

X
- Definition Collaboration term. + References No definition available. + Details
Name: | asmb_CollaborationTerm
Namespace Prefix: | asmb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Expected equity financing completion date. + References No definition available. + Details
Name: | asmb_ExpectedEquityFinancingCompletionDate
Namespace Prefix: | asmb_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of days volume considered for weighted average price to calculate premium. + References No definition available. + Details
Name: | asmb_NumberOfDaysVolumeConsideredForWeightedAveragePriceToCalculatePremium
Namespace Prefix: | asmb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of directors right to designate in board. + References No definition available. + Details
Name: | asmb_NumberOfDirectorsRightToDesignateInBoard
Namespace Prefix: | asmb_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of fellow-contributed programs. + References No definition available. + Details
Name: | asmb_NumberOfFellowContributedPrograms
Namespace Prefix: | asmb_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of timepoints of program. + References No definition available. + Details
Name: | asmb_NumberOfTimepointsOfProgram
Namespace Prefix: | asmb_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of years of standstill and lockup provisions. + References No definition available. + Details
Name: | asmb_NumberOfYearsOfStandstillAndLockupProvisions
Namespace Prefix: | asmb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage cover of research and development costs. + References No definition available. + Details
Name: | asmb_PercentageCoverOfResearchAndDevelopmentCosts
Namespace Prefix: | asmb_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of premium to weighted average price immediately prior to date of purchase. + References No definition available. + Details
Name: | asmb_PercentageOfPremiumToWeightedAveragePriceImmediatelyPriorToDateOfPurchase
Namespace Prefix: | asmb_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of premium to weighted average price immediately prior to delivery of notice of closing date. + References No definition available. + Details
Name: | asmb_PercentageOfPremiumToWeightedAveragePriceImmediatelyPriorToDeliveryOfNoticeOfClosingDate
Namespace Prefix: | asmb_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of then-outstanding voting capital stock subject to stockholder approval. + References No definition available. + Details
Name: | asmb_PercentageOfThenOutstandingVotingCapitalStockSubjectToStockholderApproval
Namespace Prefix: | asmb_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage share of profits and operating loss for products. + References No definition available. + Details
Name: | asmb_PercentageShareOfProfitsAndOperatingLossForProducts
Namespace Prefix: | asmb_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Potential Milestone Payments. + References No definition available. + Details
Name: | asmb_PotentialMilestonePayments
Namespace Prefix: | asmb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Potential proceeds from collaboration extension fees. + References No definition available. + Details
Name: | asmb_PotentialProceedsFromCollaborationExtensionFees
Namespace Prefix: | asmb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Potential proceeds from equity financing. + References No definition available. + Details
Name: | asmb_PotentialProceedsFromEquityFinancing
Namespace Prefix: | asmb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Purchase price per share of additional shares description. + References No definition available. + Details
Name: | asmb_PurchasePricePerShareOfAdditionalSharesDescription
Namespace Prefix: | asmb_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Threshold payment of opt-in fee. + References No definition available. + Details
Name: | asmb_ThresholdPaymentOfOptInFee
Namespace Prefix: | asmb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Upfront cash payment received. + References No definition available. + Details
Name: | asmb_UpfrontCashPaymentReceived
Namespace Prefix: | asmb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Cash received from collaborators during the current period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482740/230-10-45-25 + Details
Name: | us-gaap_ProceedsFromCollaborators
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Cash received on stock transaction after deduction of issuance costs. + References No definition available. + Details
Name: | us-gaap_SaleOfStockConsiderationReceivedOnTransaction
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 Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction. + References No definition available. + Details
Name: | us-gaap_SaleOfStockPricePerShare
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 830 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481674/830-30-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 855 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483399/855-10-50-2 + Details
Name: | us-gaap_SubsequentEventLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=asmb_GileadSciencesIncorporatedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=asmb_OptionLicenseAndCollaborationAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis=asmb_RegulatoryAndCommercialMilestonesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=asmb_EquityAgreementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=asmb_ThirdYearOfCollaborationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=asmb_FifthYearOfCollaborationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TypeOfArrangementAxis=asmb_SeventhYearOfCollaborationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |