Income Tax - Schedule of Reconciliations of PRC Statutory Income Tax Rate and Group's Effective Income Tax Rate (Details) - China	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Statutory income tax rate	25.00%	25.00%	25.00%
Share-based compensations	(1.51%)	(1.93%)	(3.27%)
Non-deductible expenses	(0.39%)	(0.38%)	(0.79%)
Prior year tax filing adjustment	1.93%	1.55%
Effect of different tax rate of subsidiary operation in other jurisdictions	0.07%	(0.76%)	(3.06%)
Preferential tax rate	(9.14%)
Effect of change in tax rate	(9.15%)
Changes in valuation allowance	(6.81%)	(23.48%)	(17.88%)

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to statutory income tax expense (benefit) outside of the country of domicile.

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Percentage of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to nondeductible expense for share-based payment arrangement.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to revisions of previously reported income tax expense.

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Effective income tax rate reconciliation at preferential tax rate.

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