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Notes and Accounts Receivable (Tables) | 12 Months Ended
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Dec. 31, 2020
Receivables [Abstract] |
Summary of Notes and Accounts Receivable |
|  | December 31 |
|  | 2019 |  |  | 2020 |
|  | US$ |  |  | US$ |
Trade accounts receivable |  |  | 110,351 |  |  |  | 117,387 |
Allowance for doubtful accounts |  |  | (1,617 | ) |  |  | (1,561 | )
|  |  | 108,734 |  |  |  | 115,826 |
Changes in Allowances | The changes in allowance are summarized as follows:
|  | Year Ended December 31 |
|  | 2018 |  |  | 2019 |  |  | 2020 |
|  | US$ |  |  | US$ |  |  | US$ |
Allowance for doubtful accounts |  |  |  |  |  |  |  |  |  |  |  |
Balance, beginning of year |  |  | 598 |  |  |  | 645 |  |  |  | 1,617 |
Additions (reversals) charged to expense, net |  |  | 47 |  |  |  | 1,164 |  |  |  | 15 |
Write-offs |  |  | — |  |  |  | (192 | ) |  |  | (71 | )
Balance, end of year |  |  | 645 |  |  |  | 1,617 |  |  |  | 1,561 |

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- Definition Tabular disclosure of the various types of trade accounts and notes receivable and for each the gross carrying value, allowance, and net carrying value as of the balance sheet date. Presentation is categorized by current, noncurrent and unclassified receivables. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.3,4) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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