STOCK-BASED COMPENSATION (Equity Based Compensation Schedule) (Details) - USD ($)	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Allocation of stock-based compensation expense
Stock compensation expense	$ 1,354,000	$ 963,000
Research and development expenses
Allocation of stock-based compensation expense
Stock compensation expense	633,000	531,000
General and administrative expenses
Allocation of stock-based compensation expense
Stock compensation expense	$ 721,000	$ 432,000

Amount of capitalized and expensed compensation cost from equity-based compensation arrangements.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration