Note 3 - Revenue 1 (Details Textual) Pure in Thousands, $ in Thousands |
3 Months Ended | 9 Months Ended | ||||
---|---|---|---|---|---|---|
Sep. 30, 2023
USD ($)
|
Sep. 30, 2022
USD ($)
|
Sep. 30, 2023
USD ($)
|
Sep. 30, 2022
USD ($)
|
Dec. 31, 2022
USD ($)
|
Dec. 31, 2021
USD ($)
|
|
Contract with Customer, Liability, Current | $ 1,365 | $ 1,365 | $ 372 | $ 390 | ||
Contract with Customer, Liability, Revenue Recognized | $ 0 | $ 131 | $ 368 | $ 381 | ||
Contract with Customer, Contracts in Progress, Number of Contracts Identified as Loss Contracts | 0 | 0 | 0 | |||
Revenue, Remaining Performance Obligation, Amount | $ 5,624 | $ 5,624 | ||||
Air Pollution Control [Member] | ||||||
Contract with Customer, Asset, after Allowance for Credit Loss | 1,944 | 1,944 | $ 3,082 | 1,277 | ||
FUEL CHEM [Member] | ||||||
Contract with Customer, Asset, after Allowance for Credit Loss | $ 0 | $ 0 | $ 0 | $ 0 |