COMMITMENTS AND CONTINGENCIES (Tables)
 12 Months Ended
Dec. 31, 2017
COMMITMENTS AND CONTINGENCIES [Abstract]  
Schedule of Future Minimum Payments Under Non-Cancelable Operating Leases
 
 
RMB
 
US$
 
2018
 
 
15,252
 
 
2,344
 
2019
 
 
12,460
 
 
1,915
 
2020
 
 
12,418
 
 
1,909
 
2021
 
 
8,113
 
 
1,247
 
2022
 
 
4,100
 
 
630
 
Thereafter
 
 
48,175
 
 
7,404
 
 
 
 
100,518
 
 
15,449