v3.26.1
Property, plant and equipment - Property, plant and equipment (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Property, plant and equipment    
Subtotal $ 66,267 $ 68,586
Less: Accumulated depreciation (43,741) (44,963)
Total 22,526 23,623
Land    
Property, plant and equipment    
Subtotal 1,255 1,255
Land improvements    
Property, plant and equipment    
Subtotal $ 319 319
Land improvements | Minimum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 6 years  
Land improvements | Maximum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 10 years  
Buildings    
Property, plant and equipment    
Subtotal $ 1,446 1,446
Buildings | Minimum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 25 years  
Buildings | Maximum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 39 years  
Building improvements    
Property, plant and equipment    
Subtotal $ 3,714 3,714
Building improvements | Minimum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 25 years  
Building improvements | Maximum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 39 years  
Cylinders    
Property, plant and equipment    
Subtotal $ 9,749 12,853
Cylinders | Minimum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 15 years  
Cylinders | Maximum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 30 years  
Equipment    
Property, plant and equipment    
Subtotal $ 33,924 33,870
Equipment | Minimum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 3 years  
Equipment | Maximum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 10 years  
Equipment under capital lease    
Property, plant and equipment    
Subtotal $ 315 315
Equipment under capital lease | Minimum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 5 years  
Equipment under capital lease | Maximum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 7 years  
Vehicles    
Property, plant and equipment    
Subtotal $ 2,237 2,237
Vehicles | Minimum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 3 years  
Vehicles | Maximum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 5 years  
Lab and computer equipment, software    
Property, plant and equipment    
Subtotal $ 10,234 3,339
Lab and computer equipment, software | Minimum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 2 years  
Lab and computer equipment, software | Maximum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 8 years  
Furniture and fixtures    
Property, plant and equipment    
Subtotal $ 1,125 1,125
Furniture and fixtures | Minimum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 5 years  
Furniture and fixtures | Maximum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 10 years  
Leasehold improvements    
Property, plant and equipment    
Subtotal $ 865 865
Leasehold improvements | Minimum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 3 years  
Leasehold improvements | Maximum    
Property, plant and equipment    
Property, plant and equipment, Estimated Lives 5 years  
Construction-in-progress    
Property, plant and equipment    
Subtotal $ 1,084 $ 7,248