| Accounts Receivable, Net |
Accounts Receivable, Net | | | | | | | | | | | | | As of December 31, | | 2019 | | 2020 | | (US$) | | Accounts receivable | $ | 17,283,107 | | | $ | 29,374,687 | | | Less: allowance for doubtful accounts | (1,035,542) | | | (1,534,538) | | | Accounts receivable, net | $ | 16,247,565 | | | $ | 27,840,149 | |
Movement of allowance of doubtful accounts was as follows: | | | | | | | | | | | | | As of December 31, | | 2019 | | 2020 | | (US$) | | At beginning of the period | $ | (367,044) | | | $ | (1,035,542) | | | Addition | (779,671) | | | (1,365,327) | | | Write-off | 100,276 | | | 921,061 | | | Foreign currency translation impact | 10,897 | | | (54,730) | | | At end of the period | $ | (1,035,542) | | | $ | (1,534,538) | |
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