Intangible Assets

9 Months Ended

Sep. 30, 2020

Intangible Assets

Intangible Assets

Note 6. Intangible Assets

Our patents and other intangible assets are summarized as follows:

	Weighted-	At September 30, 2020
	Average	Gross
	Amortization	Carrying		Accumulated		Net
(In thousands)	Period	Amount		Amortization		Amount
Patents	12 years	$	388	$	55	$	333
Defensive intangible assets	4 years		1,125		378		747
Customer accounts	3 years		125		57		68
Total amortizable intangible assets			1,638		490		1,148
Patents pending			523		—		523
Total intangible assets		$	2,161	$	490	$	1,671

	Weighted-	At December 31, 2019
	Average	Gross
	Amortization	Carrying		Accumulated		Net
(In thousands)	Period	Amount		Amortization		Amount
Patents	11 years	$	4,386	$	447	$	3,939
Defensive intangible assets	5 years		1,125		250		875
Customer accounts	3 years		125		37		88
Total amortizable intangible assets			5,636		734		4,902
Patents pending			410		—		410
Total intangible assets		$	6,046	$	734	$	5,312

Amortization expense was $0.1 million for each of the three months ended September 30, 2020 and 2019, and $0.3 million and $0.4 million for the nine months ended September 30, 2020 and 2019, respectively. Future amortization expenses are expected as follows:

(In thousands)
2020 (October 1 - December 31)	$	58
2021		230
2022		230
2023		200
2024		179
Thereafter		251
Total	$	1,148