Organization and Description of Business (Details) $ / shares in Units, $ in Thousands	12 Months Ended	38 Months Ended
	Dec. 31, 2025 USD ($) shares	Mar. 31, 2026 USD ($) shares	Mar. 31, 2026 £ / shares	Mar. 31, 2026 USD ($) contingentValue $ / shares	Dec. 31, 2025 £ / shares	Dec. 31, 2025 USD ($) shares	Jan. 27, 2023 USD ($)
Subsidiary, Sale of Stock [Line Items]
Receivable per company share (in USD per share) \| $ / shares				$ 38.00
Transferable contingent value \| contingentValue				1
Additional cash payment (in USD per share) \| $ / shares				$ 9.00
Accumulated deficit				$ (1,265,475)		$ (1,186,234)
Ordinary shares, nominal value (in pound sterling per share) \| £ / shares			£ 0.002		£ 0.002
Cash and cash equivalents and short-term investments				$ 533,700
ATM Program
Subsidiary, Sale of Stock [Line Items]
Sale of stock, consideration receivable (up to)							$ 250,000
Shares sold in offering (in shares) \| shares		4,663,354
Aggregate net proceeds from shares sold		$ 36,600
Underwriter Offering
Subsidiary, Sale of Stock [Line Items]
Shares sold in offering (in shares) \| shares	13,372,093
Aggregate net proceeds from shares sold	$ 269,200
Number of shares issued per ordinary share (in shares) \| shares						1
Ordinary shares, nominal value (in pound sterling per share) \| £ / shares					£ 0.002