	December 31,
	2019		2018
Raw materials	$	1,751	$	1,337
Work-in-process		1,432		1,605
Finished goods		972		655
Total inventory	$	4,155	$	3,597

Work-in-process and finished goods as of December 31, 2019 and 2018 include conversion costs and exclude the cost of insulin. All insulin inventory on hand was written off and the projected loss on the purchase commitment contract to purchase future insulin was accrued as of the end of 2015. Raw materials inventory included $0.8 million of pre-launch inventory as of December 31, 2019, which consisted of FDKP received in November 2019 that will be used to manufacture Afrezza under an enhanced manufacturing process for FDKP. Approximately 2% of the material received in November 2019 was recognized as a research and development expense and will be used by the Company for stability studies and other tests. The Company expects to receive FDA approval of the new source of FDKP in mid-2021, after which the pre-launch raw materials inventory will be reclassified as raw materials inventory for use in the manufacturing of Afrezza. The Company did not have any pre-launch raw materials inventory as of December 31, 2018.

The Company analyzed its inventory levels to identify inventory that may expire or has a cost basis in excess of its estimated realizable value. The Company also performed an assessment of projected sales and evaluated the lower of cost or net realizable value and the potential excess inventory on hand at December 31, 2019 and 2018. Inventory that was forecasted to become obsolete due to expiration is recorded in costs of goods sold in the accompanying consolidated statements of operations. During the year ended December 31, 2018, the Company recorded a write-down of inventory of approximately $2.2 million. There were no inventory write-offs for the year ended December 31, 2019.