Inventory and Other Deferred Costs

Inventory and other deferred costs consists of the following:

	December 31, 2019		December 31, 2018
	(in thousands)
Raw materials	$	5,359	$	4,085
Work-in-process		6,238		5,095
Finished products		23,032		16,391
Other deferred costs		4,898		1,817

Total inventory and other deferred costs	$	39,527	$	27,388

We had inventory on consignment at customer sites of

$1.9

million and

$1.7

million as of

December

31,

2019

and

2018,

respectively.

In connection with our RestoreFlow allograft business, other deferred costs include costs incurred for the preservation of human vascular tissues available for shipment, tissues currently in active processing, and tissues held in quarantine pending release to implantable status. By federal law, human tissues cannot be bought or sold. Therefore, the tissues we preserve are

not

held as inventory, and the costs we incur to procure and process vascular tissues are instead accumulated and deferred. These costs include fixed and variable overhead costs associated with the cryopreservation process, including primarily direct labor costs, tissue recovery fees, inbound freight charges, indirect materials and facilities costs. General and administrative expenses and selling expenses associated with the provision of these services are expensed as incurred.