Assets Manufactured for Internal Use, net

12 Months Ended

Dec. 31, 2020

Assets Manufactured for Internal Use, net

Assets Manufactured for Internal Use, net

Note 8. Assets Manufactured for Internal Use, net

Assets manufactured for internal use, included in other assets, are depreciated using the straight-line method over their 10 year estimated useful life. Their components are as follows:

	December 31,
	2020		2019
	(in thousands)
Internal use assets	$	62,462	$	56,775
Construction in process		156		5,242
Total cost		62,618		62,017
Accumulated depreciation		(24,155)		(19,259)
Assets manufactured for internal use, net	$	38,463	$	42,758

These products are used for research and development, training, and customer demonstration purposes.

Depreciation expense was $5.2 million, $3.9 million and $2.6 million for the years ended December 31, 2020, 2019 and 2018, respectively.