Prepayments and other current assets - Summary of Prepayments and other assets (Parenthetical) (Details) - USD ($)	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Prepayments and other current assets
Write-down of prepayments	$ 694,000	$ 9,745,000	$ 5,627,000
Allowance for credit loss, other receivables	0	$ 1,596,000	$ 300
Property and equipment held for sale	$ 464,000

Amount of cash outflow reducing gain (loss) contingency liability.

No definition available.

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- Definition

Amount of allowance for credit loss on receivable, classified as other and current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3)(a)(4))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

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- Definition

Amount of assets held-for-sale that are not part of a disposal group, expected to be sold within a year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 852
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481372/852-10-55-10

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 15
-Paragraph 4
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482309/360-10-15-4

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- References

No definition available.

+ Details

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