The change in the carrying value of goodwill for the three months ended March 31, 2025, categorized by reportable segment, is as follows (in thousands):


	Clear Aligner		Systems and Services		Total
Balance as of December 31, 2024	$	152,645	$	289,985	$	442,630

Foreign currency translation adjustments	3,534		11,447		14,981
Balance as of March 31, 2025	$	156,179	$	301,432	$	457,611

Acquired finite-lived intangible assets, excluding intangibles that were fully amortized, are as follows (in thousands):


	Weighted Average Amortization Period (in years)	Gross Carrying Amount as of March 31, 2025		Accumulated Amortization		Accumulated Impairment Loss		Net Carrying Value as of March 31, 2025
Existing technology	11	$	146,651	$	(56,004)	$	—	$	90,647
Customer relationships	10	21,500		(10,750)		—		10,750
Trademarks and tradenames1	7	9,800		(7,000)		—		2,800
Patents	12	480		(290)		—		190
		$	178,431	$	(74,044)	$	—	104,387
Foreign currency translation adjustments								(1,637)
Total intangible assets, net								$	102,750

1 The Weighted Average Amortization Period decreased from 10 years to 7 years due an intangible asset with a useful life of 15 years becoming fully amortized during the current quarter.


	Weighted Average Amortization Period (in years)	Gross Carrying Amount as of December 31, 2024		Accumulated Amortization		Accumulated Impairment Loss		Net Carrying Value as of December 31, 2024
Existing technology	11	$	146,651	$	(52,238)	$	—	$	94,413
Customer relationships	10	21,500		(10,079)		—		11,421
Trademarks and tradenames	10	16,600		(9,255)		(4,122)		3,223
Patents	12	480		(280)		—		200
		$	185,231	$	(71,852)	$	(4,122)	109,257
Foreign currency translation adjustments								(5,769)
Total intangible assets, net								$	103,488

The total estimated future amortization expense for these acquired finite-lived intangible assets as of March 31, 2025, is as follows (in thousands):


Fiscal Year Ending December 31,	Amortization
Remainder of 2025	$	13,827
2026	17,923
2027	15,607
2028	14,505
2029	14,505
2030	6,328
Thereafter	21,692
Total	$	104,387

Amortization expense for the three months ended March 31, 2025 and 2024 was $4.6 million and $5.0 million, respectively.