Inventories (Tables)

3 Months Ended

Mar. 31, 2019

Inventory Disclosure [Abstract]

Schedule of Inventories

Inventories were comprised of the following:

	March 31, 2019		December 31, 2018
Raw materials	$	20,813	$	19,615
Work-in-process		42,311		42,339
Finished goods		18,757		20,650
Supplies		11,552		11,592
Inventories	$	93,433	$	94,196