7. Intangible Assets

Intangible assets consist principally of acquired patents and technology, customer lists and relationships, licenses and trademarks. The Company recorded amortization expense of $0.7 million and $0.6 million for the three-month periods ended December 31, 2017 and 2016, respectively.

Intangible assets consisted of the following:

	December 31, 2017
(Dollars in thousands)	Weighted Average Original Life (Years)		Gross Carrying Amount		Accumulated Amortization			Net
Definite-lived intangible assets:
Customer lists and relationships		8.9	$	18,478	$	(8,279	)	$	10,199
Developed technology		11.7		9,334		(1,702	)		7,632
Non-compete		5.0		230		(115	)		115
Patents and other		16.5		2,321		(1,459	)		862
Subtotal				30,363		(11,555	)		18,808
Unamortized intangible assets:
In-process research and development				688		—			688
Trademarks and trade names				580		—			580
Total			$	31,631	$	(11,555	)	$	20,076

	September 30, 2017
(Dollars in thousands)	Weighted Average Original Life (Years)		Gross Carrying Amount		Accumulated Amortization			Net
Definite-lived intangible assets:
Customer lists and relationships		8.9	$	18,293	$	(7,834	)	$	10,459
Developed technology		11.7		9,297		(1,478	)		7,819
Non-compete		5.0		230		(103	)		127
Patents and other		16.5		2,321		(1,423	)		898
Subtotal				30,141		(10,838	)		19,303
Unamortized intangible assets:
In-process research and development				679		—			679
Trademarks and trade names				580		—			580
Total			$	31,400	$	(10,838	)	$	20,562

Based on the intangible assets in service as of December 31, 2017, excluding any possible future amortization associated with acquired in-process research and development (“IPR&D”), which has not met technological feasibility as of December 31, 2017, estimated amortization expense for the remainder of fiscal 2018 and each of the next five fiscal years is as follows (in thousands):

Remainder of 2018	$	2,015
2019		2,686
2020		2,511
2021		2,372
2022		2,332
2023		1,715

Future amortization amounts presented above are estimates. Actual future amortization expense may be different as a result of future acquisitions, impairments, completion or abandonment of IPR&D intangible assets, changes in amortization periods, or other factors.

The Company defines IPR&D as the value of technology acquired for which the related projects have substance and are incomplete. IPR&D acquired in a business acquisition is recognized at fair value and requires the IPR&D to be capitalized as an indefinite-lived intangible asset until completion of the IPR&D project or abandonment. Upon completion of the development project (generally when regulatory approval to market the product is obtained), an impairment assessment is performed prior to amortizing the asset over its estimated useful life. If the IPR&D projects are abandoned, the related IPR&D assets would be written off.