
As of December 31, 2022	Weighted-Average Amortization Period	Gross Carrying Amount		Accumulated Amortization		Net
Finite-lived intangible assets:
Developed technology	8.8 years	$	83,289	$	(10,113)	$	73,176
Customer relationships	15.0 years	6,383		(2,340)		4,043
Trade secrets and processes	20.0 years	5,256		(1,314)		3,942
Other	5.0 years	1,646		(1,646)		—
Total intangible assets	9.6 years	$	96,574	$	(15,413)	$	81,161


As of December 31, 2021	Weighted-Average Amortization Period	Gross Carrying Amount		Accumulated Amortization		Net
Finite-lived intangible assets:
Developed technology	8.8 years	$	62,466	$	(1,784)	$	60,682
Customer relationships	15.0 years	6,762		(2,029)		4,733
Trade secrets and processes	20.0 years	5,256		(1,051)		4,205
Other	5.0 years	1,744		(1,569)		175
Total intangible assets subject to amortization	9.8 years	$	76,228	$	(6,433)	$	69,795
Indefinite-lived intangible assets:
In-process research and development		$	20,823	$	—	$	20,823
Total intangible assets		$	97,051	$	(6,433)	$	90,618

The gross carrying amount and accumulated amortization of the customer relationships and other intangible assets are subject to foreign currency translation effects. The Company’s $5.3 million trade secrets and processes intangible asset was recognized in connection with a royalty buyout agreement during the first quarter of 2018, which is discussed further in Note “10. Commitments and Contingencies” and Note “11. Stockholders’ Equity.”

The Company reviews indefinite-lived intangible assets for impairment annually during the fourth quarter or more frequently if events or circumstances indicate that an impairment loss may have occurred. During the three months ended September 30, 2022, the Company reclassified a $20.8 million in-process research and development (“IPR&D”) asset from the Sixense acquisition to a finite-lived developed technology intangible asset upon the completion of the IPR&D project and began amortizing the intangible asset over its useful life of 8.8 years. Prior to reclassifying the IPR&D asset to a finite-lived intangible asset during the three months ended September 30, 2022, the Company performed an impairment analysis and determined that the IPR&D asset was not impaired.

The following table presents the amortization recorded related to the Company’s finite-lived intangible assets for the years ended December 31, 2022, 2021 and 2020 (in thousands):


	Year Ended December 31,
		2022		2021		2020
Cost of revenue		$	263	$	263	$	263

Sales, general and administrative		8,917		2,618		804
Total		$	9,180	$	2,881	$	1,067

As of December 31, 2022, expected amortization expense for the unamortized acquired intangible assets for the next five years and thereafter is as follows (in thousands):


	Amortization Expense
2023	$	10,207
2024	10,207
2025	10,207
2026	10,207
2027	10,207
Thereafter	30,126
Total amortization	$	81,161

During 2017, the Company entered into an exclusive technology license agreement (the “License Agreement”) that required the Company to pay an upfront payment to the licensor of $2.5 million and future revenue milestone-based payments on sales of products covered by the licensed intellectual property. The Company accounted for the transaction as an asset acquisition and recorded an indefinite-lived intangible asset as it was determined to have alternative future use. The Company recorded an indefinite-lived intangible asset equal to the total payments made and expected to be made under the License Agreement and a corresponding contingent liability for the probable future milestone payments not yet paid.

At the end of each reporting period the Company adjusted the contingent liability to reflect the amount of future milestone payments that were probable to be paid. Prior to the commercialization of products utilizing the underlying technology, any changes in the contingent liability were recorded as an adjustment between the liability balances and the gross carrying amount of the indefinite-lived intangible asset. As of December 31, 2020, there was no contingent liability balance related to probable future milestone payments under the License Agreement. As of December 31, 2019, the balance of the contingent liability related to probable future milestone payments under the License Agreement was $11.7 million, of which $0.8 million and $10.9 million were included in accrued liabilities and other non-current liabilities on the consolidated balance sheet, respectively.

Indefinite-lived intangible assets are tested for impairment at least annually during the fourth quarter or more frequently if events or changes in circumstances between annual tests indicate that it is more likely than not that the asset is impaired. During the fourth quarter of 2019, the Company completed an annual impairment analysis of the indefinite-lived intangible asset and determined that there was no impairment. The Company determined that an impairment existed in the second quarter of 2020 as a result of a triggering event in July that provided additional information about a condition that existed as of the June 30, 2020 balance sheet date. As a result, in the second quarter of 2020, the Company wrote-off the full carrying value of the indefinite-lived intangible asset and its related contingent liability, and recognized an impairment loss of $2.5 million in research and development expense in the consolidated statement of operations.