The following table summarizes our intangible assets and software development costs:

	September 30, 2019							March 31, 2019
	Gross					Net		Gross					Net
	carrying		Accumulated			carrying		carrying		Accumulated			carrying
Intangible assets (In thousands)	amount		amortization			amount		amount		amortization			amount
Amortized intangible assets:
Customer relationships	$	10,775	$	(10,775	)	$	—	$	10,775	$	(10,775	)	$	—
Non-competition agreements		2,700		(2,700	)		—		2,700		(2,700	)		—
Developed technology		10,398		(10,398	)		—		10,398		(10,398	)		—
Trade names		230		(215	)		15		230		(192	)		38
Patented technology		80		(80	)		—		80		(80	)		—
		24,183		(24,168	)		15		24,183		(24,145	)		38
Unamortized intangible assets:
Trade names		8,400	N/A				8,400		8,400	N/A				8,400
Total intangible assets	$	32,583	$	(24,168	)	$	8,415	$	32,583	$	(24,145	)	$	8,438

Software development costs (In thousands)
Total software development costs	$	67,541	$	(39,277	)	$	28,264	$	67,541	$	(32,974	)	$	34,567

The following table summarizes our remaining amortization expense relating to in service intangible assets and software development costs.

Amortization expense for software development costs related to assets to be sold, leased, or otherwise marketed was $3.1 million and $3.4 million for the three months ended September 30, 2019 and 2018, and $6.3 million and $6.0 million for the six months ended September 30, 2019 and 2018, respectively. These charges are included as costs of goods sold - products in our condensed consolidated statements of operations. Amortization expense relating to other definite-lived intangible assets was $11,500 for the three months ended September 30, 2019 and 2018, and $23,000 for the six months ended September 30, 2019 and 2018. These charges are classified as operating expenses - amortization of intangibles in our condensed consolidated statements of operations along with amortization expense related to our capitalized internal-use software that we classify in Property and equipment, net within the condensed consolidated balance sheets.

Capitalized software development costs for software internally developed to be sold, leased, or otherwise marketed, are carried on our balance sheet at carrying value, net of accumulated amortization. The Company did not capitalize any amounts for external-use software development costs during the three and six months ended September 30, 2019. Current active projects which carry a sufficiently short amount of time between achieving technological feasibility and reaching general availability to preclude capitalization. We capitalized approximately $2.0 million during the six months ended September 30, 2018.