Income taxes, Income taxes paid (net of refunds) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Income Taxes Paid, Net [Abstract]
U.S. Federal	$ 0	$ 360
State	45	60
Foreign	117	79
Total cash paid for income taxes, net of refunds	162	499
Connecticut [Member]
Income Taxes Paid, Net [Abstract]
State	25	0
Texas [Member]
Income Taxes Paid, Net [Abstract]
State	12	22
New York [Member]
Income Taxes Paid, Net [Abstract]
State	0	22
All Other [Member]
Income Taxes Paid, Net [Abstract]
State	8	16
United Kingdom [Member]
Income Taxes Paid, Net [Abstract]
Foreign	$ 117	$ 79

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

Name:	us-gaap_IncomeTaxPaidFederalAfterRefundReceived
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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

+ References

+ Details

Name:	us-gaap_IncomeTaxPaidForeignAfterRefundReceived
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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

+ References

+ Details

Name:	us-gaap_IncomeTaxPaidStateAndLocalAfterRefundReceived
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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
-Paragraph 2A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482913/230-10-50-2A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 23
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-23

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-22

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482913/230-10-50-2

+ Details

Name:	us-gaap_IncomeTaxesPaidNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_IncomeTaxesPaidNetAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=stpr_CT
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=stpr_TX
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=stpr_NY
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=us-gaap_StateAndLocalTaxJurisdictionOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeTaxAuthorityAxis=country_GB
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: