4. Goodwill and Intangible Assets

The changes in the carrying value of goodwill for the nine month period ended March 31, 2019 are as follows (in thousands):


					Optoelectronics
					and
	Security		Healthcare		Manufacturing
	Division		Division		Division		Consolidated
Balance as of June 30, 2018	$	191,810	$	40,157	$	60,246	$	292,213
Goodwill acquired or adjusted during the period		7,992		—		7,472		15,464
Foreign currency translation adjustment		(135)		6		(87)		(216)
Balance as of March 31, 2019	$	199,667	$	40,163	$	67,631	$	307,461

Intangible assets consisted of the following (in thousands):


		June 30, 2018						March 31, 2019
	Weighted	Gross						Gross
	Average	Carrying		Accumulated		Intangibles		Carrying		Accumulated		Intangibles
	Lives	Value		Amortization		Net		Value		Amortization		Net
Amortizable assets:
Software development costs	8 years	$	28,174	$	(9,423)	$	18,751	$	28,706	$	(11,730)	$	16,976
Patents	19 years		8,401		(1,618)		6,783		8,456		(1,785)		6,671
Developed technology	10 years		52,780		(9,706)		43,074		54,604		(13,861)		40,743
Customer relationships/backlog	7 years		63,398		(17,891)		45,507		66,085		(22,842)		43,243
Total amortizable assets			152,753		(38,638)		114,115		157,851		(50,218)		107,633
Non-amortizable assets:
Trademarks and trade names			25,596		—		25,596		26,509		—		26,509
IPR&D			2,290		—		2,290		2,290		—		2,290
Total intangible assets		$	180,639	$	(38,638)	$	142,001	$	186,650	$	(50,218)	$	136,432

Amortization expense related to intangible assets was $5.1 million and $5.4 million for the three months ended March 31, 2018 and 2019, respectively. For the nine months ended March 31, 2018 and 2019, amortization expense was $13.8 million and $16.3 million, respectively. At March 31, 2019, the estimated future amortization expense of intangible assets was as follows (in thousands):


2019 (remaining 3 months)	$	5,329
2020		20,022
2021		18,732
2022		14,832
2023		13,750
Thereafter, including assets that have not yet begun to be amortized		34,968
Total	$	107,633

Software development costs for software products incurred before establishing technological feasibility are charged to operations. Software development costs incurred after establishing technological feasibility are capitalized on a product-by-product basis until the product is available for general release to customers at which time amortization begins. Annual amortization, charged to cost of goods sold, is the amount computed using the ratio that current revenues for a product bear to the total current and anticipated future revenues for that product. In the event that future revenues are not estimable, such costs are amortized on a straight line basis over the remaining estimated economic life of the product. Amortizable assets that have not yet begun to be amortized are included in Thereafter in the table above. For the three months ended March 31, 2018 and 2019, we capitalized software development costs in the amounts of $1.0 million and $0.8 million, respectively. For the nine months ended March 31, 2018 and 2019, we capitalized software development costs in the amounts of $1.3 million and $1.8 million, respectively.