Significant Accounting Policies - Short-term investment and Cash and cash equivalents (Details) ¥ in Thousands, $ in Thousands	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)
Short-term investment and Cash and cash equivalents
Cash and cash equivalents	$ 49,262	¥ 342,951	¥ 413,143
Third party payment platforms
Short-term investment and Cash and cash equivalents
Cash and cash equivalents		¥ 18,715	¥ 35,375

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation and excludes interest bearing deposits.

No definition available.

Name:	coe_CashAndCashEquivalentsAtCarryingValueExcludingInterestBearingDeposits
Namespace Prefix:	coe_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant