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Principal Accounting Policies - Additional Information (Detail) ¥ in Thousands, $ in Thousands | 9 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | ---
Sep. 30, 2020 CNY (¥) | Dec. 31, 2019 CNY (¥) | Sep. 30, 2020 USD ($) | Jan. 01, 2019 CNY (¥)
Deferred subsidy income | ¥ 7,638 | ¥ 3,920 |  |
Operating lease right-of-use assets | ¥ 15,061 | ¥ 16,435 | $ 2,218 | ¥ 13,100
Operating lease, liability |  |  |  | ¥ 11,333
Minimum [Member] |  |  |  |
VAT surcharges percent | 6.00% | 6.00% |  |
Maximum [Member] |  |  |  |
VAT surcharges percent | 17.00% | 17.00% |  |
Peoples Bank of China [Member] |  |  |  |
Translation exchange rates | 6.8101 | 6.9762 | 6.8101 |
Federal Reserve Bank of New York [Member] |  |  |  |
Translation exchange rates | 6.7896 |  | 6.7896 |

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