6. Satellite Network and Other Equipment

Satellite network and other equipment consisted of the following:

	March 31,			December 31,
	2018			2017
Land	$	381		$	381
Satellite network		193,778			193,292
Capitalized software		51,676			45,062
Computer hardware		5,158			5,189
Other		5,759			5,276
Assets under construction		15,460			16,539
		272,212			265,739
Less: accumulated depreciation and amortization		(100,579	)		(91,561	)
	$	171,633		$	174,178

During the three months ended March 31, 2018 and 2017, the Company capitalized internal costs attributable to the design, development and enhancements of the Company’s products and services and internal-use software in the amount of $3,807 and $3,097, respectively.

Depreciation and amortization expense for the three months ended March 31, 2018 and 2017 was $8,942 and $8,330, respectively. This includes amortization of internal-use software of $936 and $1,351 for the three months ended March 31, 2018 and 2017, respectively.

For the three months ended March 31, 2018 and 2017, 48% and 65% of depreciation and amortization expense, respectively, relate to cost of services and 12% and 8%, respectively, relate to cost of product sales, as these assets support the Company’s revenue generating activities.

As of March 31, 2018 and December 31, 2017 assets under construction primarily consisted of costs associated with acquiring, developing and testing software and hardware for internal and external use that have not yet been placed into service.