Note 7 — Intangible assets, net

Intangible assets, net consisted of the following (in thousands):

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Amortization expense was $967,000, $838,000, and $622,000 for the years ended December 31, 2020, 2019 and 2018 respectively. The estimated aggregate amortization expense expected to be recorded in respect of these assets for each of the five years ended 2025 is $933,000, $671,000, $135,000, $nil and $nil, respectively.