INVENTORIES

3 Months Ended

Mar. 31, 2020

INVENTORIES

INVENTORIES

NOTE 6—INVENTORIES

Inventories, which are comprised of chemicals and materials available for resale and parts and consumables used in operations, are valued at the lower of cost and net realizable value, with cost determined under the weighted-average method. The significant components of inventory are as follows:

	March 31, 2020		December 31, 2019
	(in thousands)
Raw materials	$	14,070	$	12,365
Finished goods		23,988		24,724
Materials and supplies		444		453
	$	38,502	$	37,542

During the Current Quarter and Prior Quarter, the Company recorded charges to the reserve for excess and obsolete inventory for immaterial amounts of $0.1 million or less, respectively, which were recognized within costs of revenue on the accompanying consolidated statements of operations. The Company’s inventory reserve was $3.9 million and $4.1 million as of March 31, 2020 and December 31, 2019, respectively. The reserve for excess and obsolete inventories is determined based on the Company’s historical usage of inventory on hand, as well as future expectations and the amount necessary to reduce the cost of the inventory to its estimated net realizable value.