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The compensation expense recognized during the period pertaining to the deferred compensation arrangement.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Gross number of share options (or share units) granted during the period.

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Share Incentive Plan - Additional Information (Details)			1 Months Ended		12 Months Ended
Share Incentive Plan - Additional Information (Details)	Oct. 20, 2017 $ / shares shares	Oct. 20, 2017 $ / shares ¥ / shares shares	Apr. 26, 2019 CNY (¥)	Aug. 31, 2017 CNY (¥) shares	Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥) shares	Aug. 24, 2018 shares	Oct. 31, 2017 shares	Oct. 20, 2017 ¥ / shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Allocated Share-based Compensation Expense \| ¥					¥ 3,851,000	¥ 288,763,000
Dividend payout ratio assumed					0.00%
Unrecognized share-based compensation expenses \| ¥					¥ 14,083,000
Weighted average recognition period of unrecognized share-based compensation expenses					3 years 2 months 12 days
Directors and Management
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share based compensation expense \| ¥				¥ 83,133,000
Additional Ordinary Shares \| Directors and Management
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Ordinary shares issued for no consideration \| shares				146,930
Additional Ordinary Shares \| Independent Directors \| Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued in exchange for services \| ¥			¥ 1,100,000
2017 Share Incentive Plan \| Additional Ordinary Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares approved for grant \| shares							345,503	483,846
Common Stock, Capital Shares Reserved for Future Issuance \| shares							829,349
Scheme I
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares granted \| shares	363,452	363,452
Exercise price \| (per share)	$ 0.0047	$ 0.0047							¥ 0.0312
Number of shares exercised \| shares						363,452
Allocated Share-based Compensation Expense \| ¥						¥ 205,630,000
Scheme II
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares granted \| shares	66,053	66,053
Allocated Share-based Compensation Expense \| ¥					¥ 2,751,000	¥ 0
Exercise price \| (per share)	$ 84.75	$ 560.95
Scheme II \| Vested on First Anniversary Grand Date
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vesting percentage					10.00%
Scheme II \| Vested on Over Next Three Years
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vesting percentage					20.00%
Scheme II \| Vested on Third Anniversary of Company IPO
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vesting percentage					30.00%
Scheme II \| Vested on Fourth Anniversary of Company IPO
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vesting percentage					40.00%