Short-term investments (Details Textual) ¥ in Millions, $ in Millions	Sep. 30, 2015 USD ($)	Sep. 30, 2015 CNY (¥)	Dec. 31, 2014 USD ($)	Dec. 31, 2014 CNY (¥)
Time Deposits	$ 5.4	¥ 33.0	$ 2.4	¥ 15.0

Amount of deposits that cannot be withdrawn before a set date without penalty or for which notice of withdrawal is required. Time deposits include, but are not limited to, certificates of deposits, individual retirement accounts and open accounts.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.12)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Name:	us-gaap_TimeDeposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant