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FAIR VALUE MEASUREMENTS (Details) - USD ($)		3 Months Ended
	Aug. 03, 2017	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2007
Equity Investments [Line Item]
Change in fair value of equity investment		$ 125,000
Sienna | Equity​ Investment​
Equity Investments [Line Item]
Number of shares owned					13,842,625
Cost method investment, original cost				$ 0	$ 0
Trading restriction period	24 months
Change in fair value of equity investment		125,000
Accounting Standards Update 2016-01 | Sienna | Equity​ Investment​
Equity Investments [Line Item]
Cumulative effect adjustment			$ 1,189,000
Fair value of equity investment		$ 1,064,000

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
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