Inventories and Other Deferred Costs

Inventories and other deferred costs consist of the following:

	March 31, 2020		December 31, 2019
	(in thousands)
Raw materials	$	4,859	$	5,359
Work-in-process		5,987		6,238
Finished products		24,526		23,032
Other deferred costs		5,208		4,898

Total inventory and other deferred costs	$	40,580	$	39,527

We had inventory on consignment at customer sites of

1.9

million at

March 31, 2020

and

December

31,

2019.

Other deferred costs relate to our RestoreFlow allograft offering and 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 vascular tissues we preserve are

not

held as inventory, and the costs we incur to procure and process them 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.