​

  ​ ​ ​

March 31, 

  ​ ​ ​

December 31, 

  ​ ​ ​

Estimated

​

​

2026

​

2025

​

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

​

3,714

​

3,714

25-39 years

- Cylinders

​

9,749

​

12,853

15-30 years

- Equipment

​

33,924

​

33,870

3-10 years

- Equipment under capital lease

​

315

​

315

5-7 years

- Vehicles

​

2,237

​

2,237

3-5 years

- Lab and computer equipment, software

​

10,234

​

3,339

2-8 years

- Furniture and fixtures

​

1,125

​

1,125

5-10 years

- Leasehold improvements

​

865

​

865

3-5 years

- Construction-in-progress

​

1,084

​

7,248

  ​

Subtotal

​

66,267

​

68,586

  ​

Less: Accumulated depreciation

​

(43,741)

​

(44,963)

​

Total

​

$

22,526

​

$

23,623

  ​