6.   Goodwill and Intangible Assets. The change in the carrying amount of goodwill for the nine-month period ended September 30, 2026 is detailed as follows (in thousands):

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Total accumulated goodwill impairment losses aggregated to $8.3 million as of September 30, 2026 and December 31, 2025. We did not have any goodwill impairments for the nine-month periods ended September 30, 2026 or 2025.

Other intangible assets at September 30, 2026 and December 31, 2025 consisted of the following (in thousands):

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Aggregate amortization expense for developed technology and other intangible assets for the three and nine-month periods ended September 30, 2026 was $21.5 million and $63.4 million, respectively. Aggregate amortization expense for the three and nine-month periods ended September 30, 2025 was $21.8 million and $63.3 million, respectively.

We evaluate long-lived assets, including amortizing intangible assets, for impairment whenever events or changes in circumstances indicate that their carrying amounts may not be recoverable. We perform the impairment analysis at the asset group for which the lowest level of identifiable cash flows is largely independent of the cash flows of other assets and liabilities. If a triggering event is identified, we determine the fair value of our amortizing assets based on estimated future cash flows discounted back to their present value using a discount rate that reflects the risk profiles of the underlying activities. We did not identify indicators of impairment for our intangible assets based on our consideration of triggering events for the nine-month periods ended September 30, 2026 and 2025.

Estimated amortization expense for developed technology and other intangible assets for the next five years consisted of the following as of September 30, 2026 (in thousands):

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