Income taxes - Income Taxes Paid (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Income Tax [Line Items]
Domestic	$ 0	$ 0
State	131	76
Foreign	0	0
Income Taxes Paid, Net	131	76
MASSACHUSETTS
Income Tax [Line Items]
State	$ 131	$ 76

Income tax.

No definition available.

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- Definition

Amount, after income tax refund received, of cash paid to federal (national) tax jurisdiction for tax on income.

+ References

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Amount, after income tax refund received, of cash paid to foreign tax jurisdiction for tax on income.

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Amount, after income tax refund received, of cash paid to state and local tax jurisdictions for tax on income.

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Amount, after refund, of cash paid to foreign, federal, state, and local jurisdictions as income tax.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482913/230-10-50-2A

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-Topic 740
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-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
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-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-22

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