Nature of business and future operations (Details) - USD ($)		3 Months Ended
Jul. 21, 2026	Jun. 30, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash		$ 92,600,000
Long-term debt		$ 0
Genevant Sciences Corporation
Gain Contingencies [Line Items]
Ownership interest in equity method investment (as a percentage)		16.00%
Moderna \| Revenue from collaborations and licenses \| Genevant
Gain Contingencies [Line Items]
Noncontingent settlement amount		$ 950,000,000.0
Additional noncontingent settlement amount pending		$ 1,300,000,000
Genevant \| Subsequent Event
Gain Contingencies [Line Items]
Revenue recognized as portion of Settlement Agreement	$ 1,000,000.0

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