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License and Collaboration Agreements (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		111 Months Ended
	Apr. 30, 2024	Jan. 31, 2024	Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2026
License and Collaboration Agreements
License and collaboration revenue			$ 56,368	$ 28,321
Contract with customer, deferred revenue contract liability			6,300		$ 6,300
Recognized revenue from deferred revenue contract liability			3,300	5,500
License and collaboration agreement
License and Collaboration Agreements
Revenue recognized			56,400
Janssen \| Restated Agreement \| FDA approval of ICOTYDE
License and Collaboration Agreements
License and collaboration revenue			$ 50,000
Janssen \| Restated Agreement \| Minimum
License and Collaboration Agreements
Percentage of royalties on net product sales			6.00%
Janssen \| Restated Agreement \| Maximum
License and Collaboration Agreements
Percentage of royalties on net product sales			10.00%
Janssen \| License and collaboration agreement
License and Collaboration Agreements
Proceeds from Milestone Payments					387,500
Janssen \| License and collaboration agreement \| FDA approval of ICOTYDE
License and Collaboration Agreements
License and collaboration revenue			$ 50,000
Janssen \| License and collaboration agreement \| Phase 3 clinical trial for rusfertide in PV
License and Collaboration Agreements
Upcoming potential development and regulatory milestone payments receivable				425,000
Janssen \| License and collaboration agreement \| Acceptance of New Drug Application filed by Food And Drug Administration approval for second indication
License and Collaboration Agreements
Upcoming potential development and regulatory milestone payments receivable			25,000		25,000
Janssen \| License and collaboration agreement \| Acceptance of an NDA filing by the FDA for a third indication
License and Collaboration Agreements
Upcoming potential development and regulatory milestone payments receivable			35,000		35,000
Janssen \| License and collaboration agreement \| Food And Drug Administration approval of New Drug Application for second indication
License and Collaboration Agreements
Upcoming potential development and regulatory milestone payments receivable			45,000		45,000
Janssen \| License and collaboration agreement \| FDA approval of an NDA for a third indication
License and Collaboration Agreements
Upcoming potential development and regulatory milestone payments receivable			50,000		50,000
Takeda Pharmaceuticals \| License And Service
License and Collaboration Agreements
Profit (loss) share on U.S. profits and losses	50.00%
Takeda Pharmaceuticals \| Development Services
License and Collaboration Agreements
Upfront payment		$ 45,900
Takeda Pharmaceuticals \| License and collaboration agreement
License and Collaboration Agreements
Non-refundable upfront payment	$ 300,000
Final transaction price		300,000
Revenue recognized				28,300
Contract asset				22,800
Takeda Pharmaceuticals \| License and collaboration agreement \| Exercise of full opt-out right
License and Collaboration Agreements
Upcoming potential development and regulatory milestone payments receivable			775,000		$ 775,000
Takeda Pharmaceuticals \| License and collaboration agreement \| Phase 3 clinical trial for rusfertide in PV
License and Collaboration Agreements
License and collaboration revenue				22,800
Upcoming potential development and regulatory milestone payments receivable				25,000
Takeda Pharmaceuticals \| License and collaboration agreement \| Food And Drug Administration approval Of new drug application for rusfertide in PV
License and Collaboration Agreements
Upcoming potential development and regulatory milestone payments receivable		50,000
Takeda Pharmaceuticals \| License and collaboration agreement \| Food And Drug Administration approval Of new drug application for rusfertide in PV \| Exercise of full opt-out right
License and Collaboration Agreements
Upcoming potential development and regulatory milestone payments receivable		75,000
Takeda Pharmaceuticals \| License and collaboration agreement \| First regulatory approval in three European countries
License and Collaboration Agreements
Upcoming potential development and regulatory milestone payments receivable		15,000
Takeda Pharmaceuticals \| License and collaboration agreement \| First regulatory approval in japan
License and Collaboration Agreements
Upcoming potential development and regulatory milestone payments receivable		$ 10,000
Takeda Pharmaceuticals \| License and collaboration agreement \| Minimum
License and Collaboration Agreements
Percentage of royalties on ex-U.S. net sales	10.00%	14.00%
Takeda Pharmaceuticals \| License and collaboration agreement \| Maximum
License and Collaboration Agreements
Percentage of royalties on ex-U.S. net sales	17.00%	29.00%
Collaborative arrangement, milestone payment, eligible to receive	$ 305,000
Additional payment eligible to receive from a collaborative arrangement		$ 200,000
Takeda Pharmaceuticals \| License and collaboration agreement \| Maximum \| Exercise of full opt-out right
License and Collaboration Agreements
Collaborative arrangement, milestone payment, eligible to receive		975,000
Takeda Pharmaceuticals \| License and collaboration agreement \| Maximum \| Exercise of full opt out right during the initial opt out period
License and Collaboration Agreements
Collaborative arrangement, milestone payment, eligible to receive		200,000
Takeda Pharmaceuticals \| License and collaboration agreement \| License and Maintenance
License and Collaboration Agreements
Upfront payment		$ 254,100
Takeda Pharmaceuticals \| License and collaboration agreement \| Development Services
License and Collaboration Agreements
License and collaboration revenue				5,500
Final transaction price				$ 2,200
Revenue recognized			3,300
Takeda Pharmaceuticals \| License and collaboration agreement \| Rusfertide clinical trial supplies
License and Collaboration Agreements
Cost reimbursement			$ 3,100