INVENTORY

Inventory consisted of the following (in thousands):



	June 30, 2018		December 31, 2017
Raw materials	$	2,134	$	498
Work in process	3,737		3,997
Finished goods	3,265		2,854
Total	$	9,136	$	7,349

Balance Sheet classification:
Inventory	$	8,371	$	6,657
Other long-term assets	765		692
Total	$	9,136	$	7,349

Write-downs related to excess and expiring inventory are charged to either Cost of goods sold or the cost of supplied product included in Collaboration revenues. Such write-downs were $0.5 million for both the six months ended June 30, 2018 and June 30, 2017.

Inventory expected to be used in production or sold in periods more than 12 months from the date presented is classified as Other long-term assets on the accompanying Condensed Consolidated Balance Sheets. As of both June 30, 2018 and December 31, 2017, the non-current portion of inventory consisted of a portion of our finished goods.