	December 31,
	2020		2019
Raw materials	$	1,393	$	1,751
Work-in-process		2,484		1,432
Finished goods		1,096		972
Total inventory	$	4,973	$	4,155

Work-in-process and finished goods as of December 31, 2020 and 2019 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, 2020 and 2019, which consisted of FDKP received in November 2019 that will be used to manufacture Afrezza under an enhanced manufacturing process for FDKP. The Company expects to receive FDA approval of the new source of FDKP in 2023, after which the pre-launch raw materials inventory will be reclassified as raw materials inventory for use in the manufacturing of Afrezza and Tyvaso DPI.

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, 2020 and 2019. Inventory that was forecasted to become obsolete due to expiration is recorded in costs of goods sold in the accompanying consolidated statements of operations. For the year ended December 31, 2020, there was an inventory write-off of $0.5 million as a result of this assessment. There was no inventory write-off for the year ended December 31, 2019.