INVENTORIES

As of the dates indicated, inventories are comprised of the following (in thousands):



	July 31, 2018			October 31, 2017
Raw materials	$	54,003		$	52,898
Work-in-process	11,100			18,623
Finished goods	173,419			185,488
Deferred cost of goods sold	38,525			61,340
	277,047			318,349
Provision for excess and obsolescence	(49,162		)	(51,206		)
	$	227,885		$	267,143

Ciena writes down its inventory for estimated obsolescence or unmarketable inventory by an amount equal to the difference between the cost of inventory and the estimated net realizable value based on assumptions about future demand and market conditions. During the first nine months of fiscal 2018, Ciena recorded a provision for excess and obsolescence of $19.9 million, primarily related to a decrease in the forecasted demand for certain Networking Platforms products. Deductions from the provision for excess and obsolete inventory relate primarily to disposal activities.