v3.26.1
Income taxes - Principal components of the deferred tax assets and liabilities (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Deferred tax assets:        
Inventories $ 539 $ 435    
Allowance for doubtful accounts 273 521    
Intangible assets 18,477 17,224    
Plant, property and equipment 263 291    
Contract cost assets 15 202    
Accrued product warranties 3,906 3,271    
Accrued salaries and benefits 442 641    
Accounts payable, accrued expenses and other liabilities 11,353 10,471    
Donation 21 20    
Government grants 5,297 3,456    
Unrealized investment loss of equity method investments 0 174    
Operating lease liabilities 685 1,544    
Net operating loss carryforwards 84,889 69,314    
Total deferred tax assets 126,160 107,564    
Less: valuation allowance (119,072) (102,576) $ (81,830) $ (77,874)
Deferred tax assets, net of valuation allowance 7,088 4,988    
Deferred tax liabilities:        
Operating lease right-of-use assets (825) (1,640)    
Depreciation of plant, property, and equipment (3,031) (1,183)    
Unrealized investment gain of equity method investments (966) 0    
Intangible assets (3,955) (4,221)    
Total deferred tax liabilities (8,777) (7,044)    
Net deferred tax liabilities (1,689) (2,056)    
Deferred tax assets 11 14    
Deferred tax liabilities $ (1,700) $ (2,070) [1]    
[1] Restated (refer to Note 2(c))