Off-take arrangement fee (Details) (Off-take agreement, Sichuan, USD $)	1 Months Ended
Jul. 31, 2013	Sep. 30, 2013
Off-take agreement \| Sichuan
Off-take arrangement fee
One-time success fee payable to third party		$ 7,800,000
Reduction in third party fee payable	$ 400,000

Sum of the carrying amounts of deferred costs that are expected to be recognized as a charge against earnings in periods after one year or beyond the normal operating cycle, if longer.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 17

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.10)

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

Name:	us-gaap_DeferredCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant