XML 53 R41.htm IDEA: XBRL DOCUMENT
v3.21.2

Fair Value Measurement - Additional Information (Details) - USD ($) | Sep. 30, 2021 | Jan. 28, 2021 | Dec. 31, 2020 | Mar. 09, 2020
--- | --- | --- | --- | ---
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |  |
Fair value assets, transfers between Level 1, Level 2 or Level 3 | $ 0 |  | $ 0 |
Fair value liabilities, transfers between Level 1, Level 2 or Level 3 | 0 |  | 0 |
2029 Notes |  |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |  |
Debt Instrument face amount | 747,500,000 | $ 717,500,000 |  |
Estimated fair value of notes payable | 647,700,000 |  |  |
2027 Notes |  |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |  |
Debt Instrument face amount | 550,000,000.0 |  |  | $ 550,000,000.0
Estimated fair value of notes payable | $ 759,800,000 |  | $ 997,900,000 |

X
- Definition Fair value assets transfers between level one level two or level three amount. + References No definition available. + Details
Name: | bbio_FairValueAssetsTransfersBetweenLevelOneLevelTwoOrLevelThreeAmount
Namespace Prefix: | bbio_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value liabilities transfers between level one level two or level three amount. + References No definition available. + Details
Name: | bbio_FairValueLiabilitiesTransfersBetweenLevelOneLevelTwoOrLevelThreeAmount
Namespace Prefix: | bbio_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Definition Fair value portion of notes payable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19,20,22) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_NotesPayableFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bbio_TwoPointTwoFivePercentageConvertibleSeniorNotesDueTwoThousandAndTwentyNineMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bbio_TwoPointFiveZeroPercentageConvertibleSeniorNotesDueTwoThousandAndTwentySevenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |