Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Income Tax [Line Items]
Provision for income taxes	$ 0	$ 0
Operating loss carryforwards, federal	502,200,000	482,100,000
Operating loss carryforwards, state	487,800,000	457,800,000
Increase in valuation allowance	12,200,000
Legacy Millendo
Income Tax [Line Items]
Operating loss carryforwards, federal	455,800
Orphan Drug Credit
Income Tax [Line Items]
Tax credit carryforwards		7,400,000
Not Subject to Expiration
Income Tax [Line Items]
Operating loss carryforwards, federal	281,100,000
United States | Research Tax Credit Carryforward
Income Tax [Line Items]
Tax credit carryforwards	14,100,000	12,700,000
State and Local Jurisdiction | Research Tax Credit Carryforward
Income Tax [Line Items]
Tax credit carryforwards	4,100,000	$ 4,000,000
State and Local Jurisdiction | Not Subject to Expiration | Research Tax Credit Carryforward
Income Tax [Line Items]
Tax credit carryforwards	$ 3,000,000