XML 82 R44.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Summary of significant accounting policies - Research and development incentives and receivable (Details) - USD ($) $ in Millions |  |  |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | ---
Apr. 01, 2024 | Apr. 01, 2023 | Mar. 31, 2023 | Feb. 29, 2024 | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Research and development incentives and receivable |  |  |  |  |  |  |
Reduction of research and development |  |  |  |  | $ 43.1 | $ 23.5 | $ 19.3
Certain research and development expenditures incurred prior to April 1, 2023 |  |  |  |  |  |  |
Research and development incentives and receivable |  |  |  |  |  |  |
Percentage of surrenderable losses |  |  | 33.35% |  |  |  |
Certain research and development expenditures incurred thereafter April 1, 2023 |  |  |  |  |  |  |
Research and development incentives and receivable |  |  |  |  |  |  |
Percentage of surrenderable losses |  | 18.60% |  | 26.97% |  |  |
Certain research and development expenditures incurred April 1, 2024 and thereafter |  |  |  |  |  |  |
Research and development incentives and receivable |  |  |  |  |  |  |
Percentage of surrenderable losses | 40.00% |  |  |  |  |  |
Percentage of total expenditure | 30.00% |  |  |  |  |  |

X
- Definition Amount of reduction of research and development expense. + References No definition available. + Details
Name: | bcyc_ReductionOfResearchAndDevelopmentExpense
Namespace Prefix: | bcyc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage of tax credit on total expenditure during the period that arise from qualifying research and development expenses incurred by the Company's subsidiaries in the United Kingdom. + References No definition available. + Details
Name: | bcyc_ResearchAndDevelopmentPercentageOfTaxCreditOnTotalExpenditure
Namespace Prefix: | bcyc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of tax credit on surrenderable trading losses that arise from qualifying research and development expenses incurred by the Company's subsidiaries in the United Kingdom. + References No definition available. + Details
Name: | bcyc_ResearchAndDevelopmentTaxReliefsProgramPercentageOfTaxCreditOnSurrenderableLosses
Namespace Prefix: | bcyc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

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

X
- Details
Name: | srt_StatementScenarioAxis=bcyc_CertainResearchAndDevelopmentExpendituresIncurredPriorToApril12023Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementScenarioAxis=bcyc_CertainResearchAndDevelopmentExpendituresIncurredThereafterApril12023Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_StatementScenarioAxis=bcyc_CertainResearchAndDevelopmentExpendituresIncurredThereafterApril12024Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |