Inventories

12 Months Ended

Dec. 31, 2019

Inventories consisted of the following (in thousands):



	December 31,
	2019		2018
Raw materials	$	65,315	$	66,391
Work in process	53,891		58,911
Finished goods	18,103		18,380
Inventories	$	137,309	$	143,682

We regularly review inventory quantities on hand and record a provision to write-down excess and obsolete inventory to its estimated net realizable value, if less than cost, based primarily on our estimated forecast of product demand. Once our inventory value is written-down a new cost basis has been established. For 2019, 2018 and 2017, our charges for acquisition inventory step-up amortization, excess and obsolete inventory and net realizable value reserves totaled $0.4 million, $7.7 million and $7.2 million, respectively.