Adaptimmune Annual report [Section 13 and 15(d), not S-K Item 405]

Income taxes - Change in Tax Rate (Details)

v3.25.1

Income taxes - Change in Tax Rate (Details)			3 Months Ended	12 Months Ended
Income taxes - Change in Tax Rate (Details)	Apr. 01, 2023	Mar. 31, 2023	Dec. 31, 2022	Dec. 31, 2024 GBP (£)	Dec. 31, 2023 USD ($)	Dec. 31, 2022	Dec. 31, 2024 USD ($)
Income taxes
Gain on bargain purchase					$ 22,049,000
UK
Income taxes
Tax rate (as a percent)	25.00%	19.00%	19.00%	25.00%	23.50%
Difference in tax rates				25.00%
US
Income taxes
Gain on bargain purchase					$ 22,049,000
Difference in tax rates				21.00%	21.00%	21.00%
His Majesty's Revenue and Customs (HMRC) [Member]
Income taxes
Tax rate (as a percent)				25.00%	23.50%	19.00%
Operating Loss Carryforwards							$ 569,858,000
Expenditure credit carryforward							$ 1,576,000
Annual allowance \| £				£ 5,000,000
Percentage on taxable profit							50.00%
Internal Revenue Service (IRS) [Member]
Income taxes
Operating Loss Carryforwards							$ 395,887,000
Expenditure credit carryforward							$ 199,070,000
Tax credit carried forward period				20 years

- Definition

Percentage of domestic federal statutory tax rate applicable to deferred taxes.

+ References

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- Definition

Amount of expenditure credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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- Definition

Amount of annual allowance for operating loss carryforwards and tax credit carryforward.

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"Percentage on taxable profit for operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws, and the amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws."

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It represents the period of tax credit carryforwards can be carried forward.

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- Definition

In a business combination in which the amount of net identifiable assets acquired and liabilities assumed exceeds the aggregate consideration transferred or to be transferred (as defined), this element represents the amount of gain recognized by the entity.

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- Definition

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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