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v3.23.3

Property, plant and equipment (Tables) | 9 Months Ended
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Sep. 30, 2023
Property, plant and equipment |
Schedule of elements of property, plant and equipment | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ |  | September 30, |  | December 31, |  | Estimated
​ | ​ | 2023 | ​ | 2022 | ​ | Lives
(in thousands) | ​ | (unaudited) | ​ | ​ | ​ | ​ | ​
Property, plant and equipment | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
- Land | ​ | $ | 1,255 | ​ | $ | 1,255 | ​ | ​
- Land improvements | ​ |  | 319 | ​ |  | 319 |  | 6-10 years
- Buildings | ​ |  | 1,446 | ​ |  | 1,446 |  | 25-39 years
- Building improvements | ​ |  | 3,467 | ​ |  | 3,396 |  | 25-39 years
- Cylinders | ​ |  | 13,300 | ​ |  | 13,315 |  | 15-30 years
- Equipment | ​ |  | 28,920 | ​ |  | 27,258 |  | 3-10 years
- Equipment under capital lease | ​ |  | 315 | ​ |  | 315 |  | 5-7 years
- Vehicles | ​ |  | 1,789 | ​ |  | 1,773 |  | 3-5 years
- Lab and computer equipment, software | ​ |  | 3,233 | ​ |  | 3,103 |  | 2-8 years
- Furniture & fixtures | ​ |  | 933 | ​ |  | 840 |  | 5-10 years
- Leasehold improvements | ​ |  | 865 | ​ |  | 852 |  | 3-5 years
- Construction-in-progress | ​ |  | 3,741 | ​ |  | 3,533 |  |
Subtotal | ​ |  | 59,583 | ​ |  | 57,405 |  |
Less: Accumulated depreciation | ​ |  | (39,013) | ​ |  | (36,837) |  |
Total | ​ | $ | 20,570 | ​ | $ | 20,568 |  |

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- Definition Tabular disclosure of physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, balances by class of assets, depreciation and depletion expense and method used, including composite depreciation, and accumulated deprecation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 1 -SubTopic 10 -Topic 360 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482099/360-10-50-1 + Details
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