| Segment Reporting Disclosure [Text Block] |
12. BUSINESS SEGMENT AND GEOGRAPHIC FINANCIAL DATA
Business Segment Financial Data
We segregate our financial results into two reportable segments representing two broad technology segments as follows:
| | • | The Air Pollution Control technology segment includes technologies to reduce NOx emissions in flue gas generated by the firing of natural gas or coal from boilers, incinerators, furnaces and other stationary combustion sources. These include NOxOUT® Selective Non-Catalytic Reduction systems and Selective Catalytic Reduction (SCR) systems. Our SCR systems can also include Ammonia Injection Grid, and GSG™ Graduated Straightening Grid systems to provide high NOx reductions at significantly lower capital and operating costs than conventional SCR systems. ULTRA® technology creates ammonia at a plant site using safe urea for use with any SCR application. ESP technologies make use of electrostatic precipitator products and services to reduce particulate matter. FGC systems are chemical injection systems offered in markets outside the U.S. and Canada to enhance electrostatic precipitator and fabric filter performance in controlling particulate emissions. |
| | • | The FUEL CHEM® technology segment, which uses chemical processes in combination with advanced CFD and CKM boiler modeling, for the control of slagging, fouling, corrosion, opacity and other sulfur trioxide-related issues in coal-fired furnaces and boilers through the addition of chemicals into the furnace using TIFI® Targeted In-Furnace Injection™ technology. |
The “Other” classification includes those profit and loss items not allocated to either reportable segment. There are no inter-segment sales that require elimination.
Our Chief Executive Officer (CEO) serves as our Chief Operating Decision Maker (CODM) and is responsible for reviewing segment performance and making decisions regarding resource allocation. We evaluate performance and allocate resources based on revenue and gross margin by reportable segment. We do not allocate selling, general and administrative expenses, interest, other non-operating income or expense items, or taxes to segments. The accounting policies of the reportable segments are the same as those described in the summary of significant accounting policies. We do not review assets by reportable segment, but rather, in aggregate for the Company as a whole.
Information about reporting segment net sales and gross margin from continuing operations are provided below:
| For the year ended December 31, 2025 | | Air Pollution Control Segment | | | FUEL CHEM Segment | | | Other | | | Total | |
| Revenues from external customers | | $ | 8,908 | | | $ | 17,769 | | | $ | — | | | $ | 26,677 | |
| Cost of sales | | | (5,093 | ) | | | (9,201 | ) | | | — | | | | (14,294 | ) |
| Gross margin | | | 3,815 | | | | 8,568 | | | | — | | | | 12,383 | |
| Selling, general and administrative | | | — | | | | — | | | | (14,050 | ) | | | (14,050 | ) |
| Research and development | | | — | | | | — | | | | (2,014 | ) | | | (2,014 | ) |
| Operating income (loss) from continuing operations | | $ | 3,815 | | | $ | 8,568 | | | $ | (16,064 | ) | | $ | (3,681 | ) |
| For the year ended December 31, 2024 | | Air Pollution Control Segment | | | FUEL CHEM Segment | | | Other | | | Total | |
| Revenues from external customers | | $ | 11,242 | | | $ | 13,891 | | | $ | — | | | $ | 25,133 | |
| Cost of sales | | | (7,050 | ) | | | (7,460 | ) | | | — | | | | (14,510 | ) |
| Gross margin | | | 4,192 | | | | 6,431 | | | | — | | | | 10,623 | |
| Selling, general and administrative | | | — | | | | — | | | | (13,761 | ) | | | (13,761 | ) |
| Research and development | | | — | | | | — | | | | (1,564 | ) | | | (1,564 | ) |
| Operating income (loss) from continuing operations | | $ | 4,192 | | | $ | 6,431 | | | $ | (15,325 | ) | | $ | (4,702 | ) |
Geographic Segment Financial Data
Information concerning our operations by geographic area is provided below. Revenues are attributed to countries based on the location of the end-user. Assets are those directly associated with operations of the geographic area. We manage our assets on a total company basis, not by operating segment. Therefore, our CODM does not regularly review any asset information by operating segment and accordingly, we do not report asset information by operating segment.
| For the years ended December 31, | | 2025 | | | 2024 | |
| Revenues: | | | | | | | | |
| United States | | $ | 21,022 | | | $ | 17,802 | |
| Other Foreign | | | 5,655 | | | | 7,331 | |
| | | $ | 26,677 | | | $ | 25,133 | |
| As of December 31, | | 2025 | | | 2024 | |
| Assets: | | | | | | | | |
| United States | | $ | 44,345 | | | $ | 44,430 | |
| Foreign | | | 2,834 | | | | 4,367 | |
| | | $ | 47,179 | | | $ | 48,797 | |
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