BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES, Returns Asset and Refund Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Refund liabilities	$ 648,000	$ 537,000	$ 415,000
Asset returns	$ 250,000	$ 0	$ 0

Amount of liability for consideration received or receivable from customer which is not included in transaction price, when consideration is expected to be refunded to customer, classified as current.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 55
-Paragraph 27
-URI http://asc.fasb.org/extlink&oid=108792157&loc=SL49130611-203046-203046

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