The amount of outstanding funds that the entity is obligated to repay.

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The amount of financial assets at amortised cost. The amortised cost is the amount at which financial assets are measured at initial recognition minus principal repayments, plus or minus the cumulative amortisation using the effective interest method of any difference between that initial amount and the maturity amount, and adjusted for any impairment. [Refer: Financial assets]

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The fair value of financial assets. [Refer: At fair value [member]; Financial assets]

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The amount of financial liabilities at amortised cost. The amortised cost is the amount at which financial liabilities are measured at initial recognition minus principal repayments, plus or minus the cumulative amortisation using the effective interest method of any difference between that initial amount and the maturity amount. [Refer: Financial liabilities]

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The fair value of financial liabilities. [Refer: At fair value [member]; Financial liabilities]

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Number of shares converted.

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Financial instruments, Disclosure of financial assets and liabilities (Details)	Dec. 31, 2020 GBP (£)	Mar. 31, 2020 USD ($) shares	Mar. 02, 2020 USD ($) shares	Dec. 31, 2019 GBP (£)	Dec. 31, 2019 USD ($)
Financial assets at amortized cost [Abstract]
Financial assets	£ 136,307,000			£ 80,545,000
Financial assets, at fair value	136,307,000			80,545,000
Financial liabilities at amortized cost [Abstract]
Financial liabilities	61,738,000			39,863,000
Financial liabilities, at fair value	61,738,000			39,863,000
Borrowings outstanding	36,654,000			0
Gates Foundation Convertible Loan [Member]
Financial liabilities at amortized cost [Abstract]
Borrowings outstanding \| $		$ 25,000,000	$ 25,000,000		$ 25,500,000
Stock converted (in shares) \| shares		203,697
Gates Foundation Convertible Loan [Member] \| Series B Shares [Member]
Financial liabilities at amortized cost [Abstract]
Stock converted (in shares) \| shares		203,697	203,697
Trade Receivables [Member]
Financial assets at amortized cost [Abstract]
Financial assets	1,797,000			1,471,000
Financial assets, at fair value	1,797,000			1,471,000
Interest Receivable [Member]
Financial assets at amortized cost [Abstract]
Financial assets	0			28,000
Financial assets, at fair value	0			28,000
Current Clinical Trial Deposits and Accrued Income [Member]
Financial assets at amortized cost [Abstract]
Financial assets	1,221,000			424,000
Financial assets, at fair value	1,221,000			424,000
Non-current Financial Assets [Member]
Financial assets at amortized cost [Abstract]
Financial assets	3,573,000			4,390,000
Financial assets, at fair value	3,573,000			4,390,000
Embedded Derivative Asset [Member]
Financial assets at amortized cost [Abstract]
Financial assets	0			266,000
Financial assets, at fair value	0			266,000
Embedded Derivative Asset [Member] \| Level 3 [member]
Financial assets at amortized cost [Abstract]
Financial assets, at fair value				266,000
Embedded Derivative Asset [Member] \| Level 3 [member] \| Bottom of Range [Member]
Financial assets at amortized cost [Abstract]
Financial assets, at fair value	0
Embedded Derivative Asset [Member] \| Level 3 [member] \| Top of Range [Member]
Financial assets at amortized cost [Abstract]
Financial assets, at fair value				8,855,000
Cash and Cash Equivalents [Member]
Financial assets at amortized cost [Abstract]
Financial assets	129,716,000			73,966,000
Financial assets, at fair value	129,716,000			73,966,000
Trade Payables [Member]
Financial liabilities at amortized cost [Abstract]
Financial liabilities	25,084,000			15,579,000
Financial liabilities, at fair value	25,084,000			15,579,000
Interest Bearing Loans and Borrowings [Member]
Financial liabilities at amortized cost [Abstract]
Financial liabilities	36,654,000			19,157,000
Financial liabilities, at fair value	36,654,000			19,157,000
Derivative Liability [Member]
Financial liabilities at amortized cost [Abstract]
Financial liabilities	0			5,127,000
Financial liabilities, at fair value	£ 0			£ 5,127,000