Liquidity - Additional Information (Detail)			1 Months Ended	12 Months Ended
	May 09, 2024 USD ($) $ / shares shares	Oct. 02, 2023 USD ($) $ / shares shares	Mar. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2024 USD ($) Tranche	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Jul. 19, 2024 USD ($)	Dec. 16, 2022 USD ($)
Cash And Cash Equivalents [Line Items]
Net Income (Loss)				$ (175,850,000)	$ (38,988,000)	$ (24,067,000)
Accumulated deficit				(452,260,000)	(276,410,000)
Cash and cash equivalents				87,928,000	169,681,000
Marketable securities				$ 230,700,000
Number of tranches | Tranche				3
Net cash used in operating activities				$ (69,096,000)	(24,940,000)	(20,781,000)
Proceeds from issuance or sale of equity					129,000,000
Proceeds from the sale of common stock, net of issuance costs				148,955,000	0	0
Securities Purchase Agreement [Member]
Cash And Cash Equivalents [Line Items]
Sale and issuance of warrants				10,000,000
Proceeds from warrant exercise				44,800,000
Warrants aggregate exercise price				5,200,000
Jefferies LLC [Member] | Maximum [Member]
Cash And Cash Equivalents [Line Items]
Aggregrate Offering Price							$ 150,000,000
Loan and Security Agreement [Member] | Oxford [Member]
Cash And Cash Equivalents [Line Items]
Long-term debt outstanding				50,000,000
Loan available in additional tranches				$ 100,000,000
Debt instrument interest period				48 months
Debt instrument term				60 months
Debt Instrument interest rate stated percentage				5.50%
Debt instrument maturity extension period				12 months
Loan and Security Agreement [Member] | Oxford [Member] | Contingent upon FDA Approval of DCCR for Treatment of PWS Tranche One [Member]
Cash And Cash Equivalents [Line Items]
Debt instrument additional borrowing amount				$ 50,000,000
Loan and Security Agreement [Member] | Oxford [Member] | Contingent upon FDA Approval of DCCR for Treatment of PWS Tranche Two [Member]
Cash And Cash Equivalents [Line Items]
Debt instrument additional borrowing amount				25,000,000
Loan and Security Agreement [Member] | Oxford [Member] | Contingent upon Certain Commercial Milestones [Member]
Cash And Cash Equivalents [Line Items]
Debt instrument additional borrowing amount				25,000,000
Loan and Security Agreement [Member] | Oxford [Member] | Mutual Consent of Soleno and Oxford [Member]
Cash And Cash Equivalents [Line Items]
Debt instrument additional borrowing amount				50,000,000
Tranche A [Member]
Cash And Cash Equivalents [Line Items]
ExercisableWarrants Maximum Aggregate Exercise price								$ 15,000,000
Tranche B [Member]
Cash And Cash Equivalents [Line Items]
Contingent receipt upon exerise of warrants and future performance of company				5,200,000
Proceeds from warrant exercise				$ 29,800,000
ExercisableWarrants Maximum Aggregate Exercise price								$ 35,000,000
Underwritten Public Offering [Member]
Cash And Cash Equivalents [Line Items]
Issuance of common stock (shares) | shares	3,450,000	3,450,000	2,666,667
Price per unit | $ / shares	$ 46	$ 20	$ 3.75
Proceeds from offering after deducting underwriting discount and other estimated offering expenses	$ 158,700,000	$ 69,000,000	$ 13,800,000
Underwriter discount and other offering expenses	$ 9,700,000
Proceeds from warrant exercise					$ 0
Underwritten Public Offering [Member] | Securities Purchase Agreement [Member] | Maximum [Member]
Cash And Cash Equivalents [Line Items]
Proceeds from the sale of common stock, net of issuance costs						$ 60,000,000