5.    GOODWILL AND OTHER INTANGIBLE ASSETS

Goodwill

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

​

​

Gross goodwill and accumulated impairment losses was $84,781 and $7,585, respectively, as of September 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 September 30, 2022 and December 31, 2021:

​

​

​

​

The Company recorded amortization expense of $2,274 and $2,173 for the three months ended September 30, 2022 and 2021, respectively, of which $134 and $198 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 nine months ended September 30, 2022 and 2021 was $6,671 and $6,538, respectively, of which $314 and $596 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 definite-lived intangible assets for the remaining three months of 2022, the next four years and thereafter is as follows:

​

​