Inventories

Inventories consist of the following:



	As of December 31,
	2016		2015
Raw materials	$	92,287	$	59,151
Work-in-process	202,301		132,068
Finished goods	13,334		11,197
Deferred costs	91,434		36,162
	$	399,356	$	238,578

Deferred costs represent the costs of product manufactured and shipped to the Company's collaborators for which recognition of revenue has been deferred (see Note 1). For the years ended December 31, 2016, 2015, and 2014, cost of goods sold included inventory write-downs and reserves totaling $14.0 million, $10.6 million, and $6.0 million, respectively.