NET LOSS PER SHARE - Potentially Dilutive Securities (Details) - shares	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019
Potentially dilutive securities	27,223,000	27,574,000
Common stock options
Common stock purchase warrants	5,842,000	4,568,000
Common stock purchase warrants
Common stock purchase warrants	21,381,000	22,979,000
Common stock warrants - liability treatment
Common stock purchase warrants	0	27,000

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Name:	us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration