Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Liabilities (Details) ¥ in Thousands, $ in Thousands	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 CNY (¥)
Payables And Accruals [Abstract]
Salary and welfare payables	¥ 124,137		¥ 148,337
Accrued marketing expenses	120,269		16,133
Accrued rental expenses	51,087		33,693
Accrued service fees	94,789		13,595
Other tax liabilities	29,872		9,915
Advanced deposits	6,650		6,081
Refund liability	6,625		2,452
Payables for leasehold improvement and intangible assets	4,911		2,180
American Depositary Receipt commission - within one year	3,482
Payables to educational institutions	6,024
Payables for share repurchase	857
Other payables	6,581		3,514
Total	¥ 455,284	$ 66,218	¥ 235,900

American depositary receipt commision refund current.

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Payables for leasehold improvement and intangible assets.

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Payables for share repurchase.

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Payables to educational institutions.

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Amount of obligations incurred classified as other, payable within one year or the normal operating cycle, if longer.

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Carrying value as of the balance sheet date of obligations incurred and payable for real and property taxes. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Carrying value as of the balance sheet date of obligations incurred through that date and payable for the marketing, trade and selling of the entity's goods and services. Marketing costs would include expenditures for planning and executing the conception, pricing, promotion, and distribution of ideas, goods, and services; costs of public relations and corporate promotions; and obligations incurred and payable for sales discounts, rebates, price protection programs, etc. offered to customers and under government programs. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Carrying value as of the balance sheet date of obligations incurred through that date and payable for professional fees, such as for legal and accounting services received. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Carrying value as of the balance sheet date of obligations incurred through that date and payable for contractual rent under lease arrangements. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Amount of liability for consideration received or receivable from customer which is not included in transaction price, when consideration is expected to be refunded to customer, classified as current.

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Current regulatory liabilities generally represent obligations to make refunds to customers for various reasons including overpayment.

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Total of the carrying values as of the balance sheet date of obligations incurred through that date and payable for obligations related to services received from employees, such as accrued salaries and bonuses, payroll taxes and fringe benefits. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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