v3.26.1
Note 3 - Revenue - Revenues Disaggregated by Product Technology (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Revenues $ 6,485 $ 5,558 $ 12,565 $ 11,940
Air Pollution Control [Member]        
Revenues 2,785 2,505 4,389 3,808
Air Pollution Control [Member] | Technology Solutions [Member]        
Revenues 2,078 1,644 2,833 2,216
Air Pollution Control [Member] | Spare Parts [Member]        
Revenues 417 425 811 675
Air Pollution Control [Member] | Ancillary Revenue [Member]        
Revenues 290 436 745 917
FUEL CHEM [Member]        
Revenues 3,700 3,053 8,176 8,132
FUEL CHEM [Member] | Technology Solutions [Member]        
Revenues $ 3,700 $ 3,053 $ 8,176 $ 8,132