Basis of Presentation and Consolidation and Summary of Significant Accounting Policies - Prepaid expenses and other current assets (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Prepaid expenses		$ 566	$ 533
Stock subscription receivable		1,362	0
Other current assets		189	226
Prepaid expenses and other current assets	$ 2,138	$ 2,117	$ 759

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Amount of current assets classified as other.

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Amount of asset related to consideration paid in advance for costs that provide economic benefits in future periods, and amount of other assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer.

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Carrying amount as of the balance sheet date of expenditures made in advance of when the economic benefit of the cost will be realized, and which will be expensed in future periods with the passage of time or when a triggering event occurs.

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Note received instead of cash as contribution to equity. The transaction may be a sale of capital stock or a contribution to paid-in capital.

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