INVENTORIES

Inventories are stated at the lower of cost (first-in, first-out) or net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. We write down the carrying value of inventory for estimated obsolescence by an amount equal to the difference between the cost of inventory and the estimated market value when warranted based on assumptions of future demand, market conditions, remaining shelf life, or product functionality. If actual market conditions or results of estimated functionality are less favorable than those we estimated, additional inventory write-downs may be required, which would have a negative effect on results of operations.

Unpaid inventory reflected within accounts payable in our consolidated balance sheets was $41.3 million, $37.2 million, and $32.7 million at December 31, 2018, 2017 and 2016, respectively.

The components of inventories are as follows (in thousands):



	December 31, 2018		December 31, 2017

Raw materials	$	31,973	$	32,994
Work-in-process	17,009		17,786
Finished goods	124,321		113,538
Inventories (Note 2)	$	173,303	$	164,318