CONCENTRATIONS (Details) ¥ in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2018 CNY (¥)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2018 USD ($)
CONCENTRATIONS [Line Items]
Accounts receivable	¥ 18,132	¥ 24,511	$ 2,637
Prepaid and other current assets	¥ 134,770	¥ 129,517	$ 19,601
Accounts receivable [Member] \| Credit risk [Member] \| Company A [Member]
CONCENTRATIONS [Line Items]
Concentration risk (as a percent)	0.00%	23.00%
Accounts receivable	¥ 0	¥ 5,656
Prepaid and other current assets [Member] \| Credit risk [Member] \| Company B [Member]
CONCENTRATIONS [Line Items]
Concentration risk (as a percent)	37.00%	38.00%
Prepaid and other current assets	¥ 49,800	¥ 49,800
Prepaid and other current assets [Member] \| Credit risk [Member] \| Company C [Member]
CONCENTRATIONS [Line Items]
Concentration risk (as a percent)	26.00%	27.00%
Prepaid and other current assets	¥ 35,000	¥ 35,000

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

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