v3.26.1
INCOME TAXES - Reconciliation of income tax (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Amount      
Tax benefit at statutory federal rate $ 9,632 $ 7,994 $ 5,521
Attribute expiration   (1,899) (28,281)
Nondeductible expenses   (558) (1,469)
Change in valuation allowance   (1,636) 23,864
Research and development bonus deduction   100 121
Tax rate differential   (119) 841
Tax shortfalls from share options   (4,129) (830)
Others   $ 247 314
Total     $ 81
Tax Jurisdiction of Domicile [Extensible Enumeration] UNITED STATES    
Percent      
Federal statutory rate (as a percent) 21.00% 21.00% 21.00%
UNITED STATES      
Amount      
Attribute expiration $ (2,381)    
Nondeductible expenses (90)    
Change in valuation allowance (3,222)    
Tax shortfalls from share options $ (118)    
Percent      
Attribute expiration (5.20%)    
Nondeductible expenses (0.20%)    
Change in valuation allowance (7.00%)    
Tax shortfalls from share options (0.30%)    
CHINA      
Amount      
Attribute expiration $ (1,059)    
Nondeductible expenses (926)    
Change in valuation allowance (1,307)    
Research and development bonus deduction 100    
Tax rate differential 667    
Others $ (978)    
Percent      
Attribute expiration (2.30%)    
Nondeductible expenses (2.00%)    
Change in valuation allowance (2.80%)    
Research and development bonus deduction 0.20%    
Tax rate differential 1.50%    
Others (2.10%)    
HONG KONG      
Amount      
Change in valuation allowance $ (125)    
Tax rate differential $ (193)    
Percent      
Change in valuation allowance (0.30%)    
Tax rate differential (0.40%)