Quarterly report pursuant to Section 13 or 15(d)

Inventories (Details)

v3.21.2
Inventories (Details) - USD ($)
$ in Thousands
Sep. 30, 2021
Dec. 31, 2020
Inventory Disclosure [Abstract]    
Supplies $ 5,165 $ 6,312
Raw materials 731 613
Work in process 2,900 3,478
Finished goods 642 1,617
Total inventories $ 9,438 $ 12,020