Consolidated Balance Sheets (Parenthetical) ¥ in Thousands, $ in Thousands |
Dec. 31, 2017
CNY (¥)
shares
|
Dec. 31, 2017
USD ($)
$ / shares
shares
|
Dec. 31, 2016
CNY (¥)
shares
|
|---|---|---|---|
| Allowance for doubtful accounts | ¥ 1,408 | $ 216 | ¥ 512 |
| Total current liabilities | 3,889,316 | 597,778 | 2,544,040 |
| Total non-current liabilities | 470,373 | 72,295 | 496,773 |
| Total liabilities | ¥ 4,359,689 | $ 670,073 | ¥ 3,040,813 |
| Ordinary shares, shares authorized | 100,000,000,000 | 100,000,000,000 | 100,000,000,000 |
| Consolidated VIEs [Member] | |||
| Total current liabilities | ¥ 259,986 | $ 39,959 | ¥ 291,685 |
| Total non-current liabilities | 32,718 | 5,028 | 28,531 |
| Total liabilities | ¥ 292,704 | $ 44,987 | ¥ 320,216 |
| Class A Ordinary Shares [Member] | |||
| Ordinary shares, par value | $ / shares | $ 0.01 | ||
| Ordinary shares, shares authorized | 99,931,211,060 | 99,931,211,060 | 99,931,211,060 |
| Ordinary shares, shares issued | 117,140,856 | 117,140,856 | 115,297,224 |
| Ordinary shares, shares outstanding | 117,140,856 | 117,140,856 | 115,297,224 |
| Class B Ordinary Shares [Member] | |||
| Ordinary shares, par value | $ / shares | $ 0.01 | ||
| Ordinary shares, shares authorized | 68,788,940 | 68,788,940 | 68,788,940 |