SUMMARY OF PRINCIPAL ACCOUNTING POLICIES (Concentration of Credit Risk) (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Concentration of credit risk
Accounts receivable, allowance for doubtful accounts	$ 7,993	$ 10,163
Accounts receivable	2,971,930	4,836,499
Customer A [Member]
Concentration of credit risk
Accounts receivable	1,286,454	1,368,956
Customer B [Member]
Concentration of credit risk
Accounts receivable	984,918	1,576,400
Customer C [Member]
Concentration of credit risk
Accounts receivable	$ 682,264	$ 1,294,342

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(4))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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