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Significant Accounting Policies (Details) ¥ / shares in Units, ¥ in Thousands, $ in Thousands | 6 Months Ended | 12 Months Ended | 14 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Jun. 30, 2021 CNY (¥) | Jun. 30, 2020 CNY (¥) | Dec. 31, 2020 CNY (¥) ¥ / shares | Dec. 31, 2020 USD ($) | Dec. 31, 2019 CNY (¥) | Dec. 31, 2018 CNY (¥) | Feb. 28, 2021 CNY (¥) | Feb. 28, 2021 USD ($) | Jun. 30, 2021 USD ($) | Mar. 31, 2021 CNY (¥) | Dec. 31, 2020 USD ($) | Nov. 30, 2020 CNY (¥) | Apr. 30, 2019
Significant Accounting Policies (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Working capital | ¥ 46,513 |  | ¥ 371,553 |  |  |  |  |  |  |  |  |  |
Accumulated deficit | (2,538,327) |  | (2,240,205) |  | ¥ (1,750,475) |  |  |  | $ (393,137) |  | $ (343,326) |  |
Loss from operations |  |  | (494,700) |  | (705,700) | ¥ (456,900) |  |  |  |  |  |  |
Cash flows from operating activities |  |  | (17,337) |  | (223,357) | 52,071 |  |  |  |  |  |  |
Line of credit |  |  | 90,000 |  |  |  |  |  |  |  |  |  |
Impairment loss on right of use assets |  |  | 4,667 |  | 21,103 | 94,311 |  |  |  |  |  |  |
Impairment loss on property plant equipment |  |  | 3,460 |  | 9,479 | 16,892 |  |  |  |  |  |  |
Impairment loss property held for sale |  |  | ¥ 36,505 | $ 5,595 | 52,030 | 111,203 |  |  |  |  |  |  |
Buying rate per share (in Yuan Renminbi per share) | ¥ / shares |  |  | ¥ 6,525 |  |  |  |  |  |  |  |  |  |
Notes payable |  |  | ¥ 267,558 |  | 267,558 |  |  |  |  |  |  |  |
Voting percentage |  |  |  |  |  |  |  |  |  |  |  |  | 100.00%
Other income |  |  | ¥ 13,931 |  | 16,782 | 31,783 |  |  |  |  |  |  |
Uncertain income tax percentage |  |  | 50.00% | 50.00% |  |  |  |  |  |  |  |  |
Cash and cash equivalents |  |  | ¥ 123,385 |  | 171,915 |  |  |  |  |  |  |  |
Short term borrowings | 1,000 |  | ¥ 1,000 |  | 28,788 |  |  |  |  |  |  |  |
Concentration risk, description |  |  | There are two customers individually represent greater than 10% of total net revenue for the year ended December 31, 2019, while there is no customer individually represent greater than 10% of total net revenue for the year ended December 31, 2020. There is one customer individually represent greater than 10% of total accounts receivable as of December 31, 2019, while there are three customers individually represent greater than 10% of total accounts receivable as of December 31, 2020.There are no suppliers that individually represent greater than 10% of the total cost of revenue (excluding impairment loss) for the years ended December 31, 2019 and 2020. | There are two customers individually represent greater than 10% of total net revenue for the year ended December 31, 2019, while there is no customer individually represent greater than 10% of total net revenue for the year ended December 31, 2020. There is one customer individually represent greater than 10% of total accounts receivable as of December 31, 2019, while there are three customers individually represent greater than 10% of total accounts receivable as of December 31, 2020.There are no suppliers that individually represent greater than 10% of the total cost of revenue (excluding impairment loss) for the years ended December 31, 2019 and 2020. |  |  |  |  |  |  |  |  |
working capital deficit | 282,583 |  |  |  |  |  |  |  |  |  |  |  |
Shareholder equity amount | 2,174,604 |  |  |  |  |  |  |  |  |  |  |  |
Accumulated deficit | 2,538,327 |  |  |  |  |  |  |  |  |  |  |  |
Losses from operations | 315,031 |  |  |  |  |  |  |  |  |  |  |  |
Operating activities amount | 109,696 |  |  |  |  |  |  |  |  |  |  |  |
Lease liability | 329,096 |  |  |  |  |  |  |  |  |  |  |  |
Unused credit line | ¥ 20,000 |  |  |  |  |  |  |  |  |  |  |  |
Going concern term | 12 months |  |  |  |  |  |  |  |  |  |  |  |
Daily operations issuance term | 12 months |  |  |  |  |  |  |  |  |  |  |  |
Impairment losses on assets | ¥ 3,397 | ¥ 4,980 |  |  |  |  |  |  |  |  |  |  |
Impairment losses on property and equipment | 6,345 | 104 |  |  |  |  |  |  |  |  |  |  |
Impairment losses on property held for sale |  | ¥ 28,378 |  |  |  |  |  |  |  |  |  |  |
Convenience calculated rate description | 00=RMB6.4566 representing the noon buying rate set forth in the H.10 statistical release of the U.S. Federal Reserve Board on June 30, 2021. |  |  |  |  |  |  |  |  |  |  |  |
Lease initial term | 12 months |  |  |  |  |  |  |  |  |  |  |  |
Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Significant Accounting Policies (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Financing proceeds through ipo |  |  |  |  |  |  | ¥ 120,791 | $ 18,512 |  |  |  |  |
Unused lines of Credit [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Significant Accounting Policies (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Line of credit |  |  |  |  |  |  |  |  |  | ¥ 20,000 |  |  |
PRC Commercial Bank [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Significant Accounting Policies (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Line of credit |  |  |  |  |  |  |  |  |  |  |  | ¥ 90,000 |
Term deposit to the commercial bank |  |  | ¥ 4,760 |  |  |  |  |  |  |  |  |  |
PRC Commercial Bank One [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Significant Accounting Policies (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Term deposit to the commercial bank |  |  | ¥ 6,750 |  |  |  |  |  |  |  |  |  |
Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Significant Accounting Policies (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Voting percentage |  |  | 20.00% |  |  |  |  |  |  |  | 20.00% |  |
Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Significant Accounting Policies (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Voting percentage |  |  | 50.00% |  |  |  |  |  |  |  | 50.00% |  |
Right of Use Assets [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Significant Accounting Policies (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Impairment loss property held for sale |  |  | ¥ 28,378 |  | ¥ 21,448 |  |  |  |  |  |  |  |
Notes Payable [Member] |  |  |  |  |  |  |  |  |  |  |  |  |
Significant Accounting Policies (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Notes payable |  |  | ¥ 29,159 |  |  |  |  |  |  |  |  |  |

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- Definition Description of risks that arise due to the volume of business transacted with a particular customer. At a minimum, the description informs financial statement users of the general nature of the risk, but excludes "Information about Major Customers" that may be disclosed elsewhere (for instance, segment disclosures). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 16 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6327-108592 + Details
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