5.    GOODWILL AND OTHER INTANGIBLE ASSETS

Goodwill

The following table summarizes the changes in goodwill for the three and six months ended June 30, 2022:

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Gross goodwill and accumulated impairment losses was $85,612 and $7,585, respectively, as of June 30, 2022 and $73,899 and $7,585, respectively, as of December 31, 2021.

Intangible Assets

Intangible assets such as certain customer relationships and patents on core technologies and product technologies are amortizable over their estimated useful lives. Certain trade names and trademarks which provide exclusive and perpetual rights to manufacture and sell their respective products are deemed indefinite-lived and are therefore not subject to amortization.

Intangible assets consisted of the following as of June 30, 2022 and December 31, 2021:

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The Company recorded amortization expense of $2,240 and $2,179 for the three months ended June 30, 2022 and 2021, respectively, of which $130 and $200 was included in cost of goods sold in the consolidated statements of operations and comprehensive income (loss) for the respective periods. Amortization expense for the six months ended June 30, 2022 and 2021 was $4,397 and $4,365, respectively, of which $180 and $398 was included in cost of goods sold in the consolidated statements of operations and comprehensive income (loss) for the respective periods.

The estimated amortization expense for finite-lived intangible assets for the remaining six months of 2022, the next four years and thereafter is as follows:

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