Assets Manufactured for Internal Use, net

12 Months Ended

Dec. 31, 2021

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,
	2021		2020
	(in thousands)
Internal use assets	$	60,596	$	62,462
Construction in process		172		156
Total cost		60,768		62,618
Accumulated depreciation		(28,764)		(24,155)
Assets manufactured for internal use, net	$	32,004	$	38,463

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

Depreciation expense was $5.3 million, $5.2 million and $3.9 million for the years ended December 31, 2021, 2020 and 2019, respectively.