STOCKHOLDERS' EQUITY (Common Stock, 2018 Purchase Agreement and LP Purchase Agreement) (Details)									1 Months Ended		3 Months Ended		12 Months Ended		27 Months Ended
	Apr. 08, 2020 shares	Apr. 06, 2020 USD ($) shares	Mar. 26, 2020 USD ($) D $ / shares shares	Jan. 14, 2020 shares	Aug. 09, 2019 shares	Feb. 01, 2019 shares	Sep. 14, 2018 shares	Sep. 07, 2018 USD ($) $ / shares shares	May 13, 2020 USD ($) shares	Apr. 30, 2020 shares	Mar. 31, 2020 USD ($) shares	Mar. 31, 2019 USD ($) shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($) shares	Mar. 31, 2020 USD ($) shares	Jan. 29, 2019 USD ($)	Jan. 01, 2019 shares	Dec. 20, 2018 shares	Sep. 06, 2018 shares
Class of Stock [Line Items]
Common stock, shares authorized (in shares)											150,000,000		150,000,000		150,000,000		250,000,000	150,000,000
Common stock, shares outstanding (in shares)			8,870,129								9,506,126		7,898,117		9,506,126				1,543,724
Issuance of common stock, net of issuance costs | $											$ 1,350,000	$ 1,726,000
Conversion of interest on convertible debt into common stock | $											325,000	2,933,000
Conversion of debt into stock | $											$ 325,000	$ 2,933,000
Shares issued (in shares)											9,506,126		7,898,117		9,506,126
Common Stock
Class of Stock [Line Items]
Conversion of convertible notes into common stock (in shares)											427,997	1,248,115
Common stock issued in connection with the conversion of convertible notes											427,997	1,248,115
Conversion of interest on convertible debt into common stock | $											$ 400,000	$ 3,100,000
Number of shares converted from debt instrument (in shares)											427,997	1,248,115
Conversion of debt into stock | $											$ 400,000	$ 3,100,000
Preferred Class B
Class of Stock [Line Items]
Number of shares converted (in shares)											0	0
Leviston Resources LLC
Class of Stock [Line Items]
Conversion of convertible notes into common stock (in shares)											73,333		111,024
Conversion of interest on convertible debt into common stock | $											$ 200,000		$ 500,000
Number of shares converted from debt instrument (in shares)											73,333		111,024
Conversion of debt into stock | $											$ 200,000		$ 500,000
Leviston Resources LLC | Settled Litigation
Class of Stock [Line Items]
Issuance of convertible notes | $																$ 700,000
Lincoln Park [Member]
Class of Stock [Line Items]
New shares issued (in shares)				920,654	1,800,000	1,000,000	466,667	40,000
Value of shares issued | $								$ 10,000,000
Maximum percentage of shares issued								19.99%
Maximum number of shares issued								308,590
Beneficial Ownership Cap								4.99%
Shares sold in offering (in shares)		110,640							500,000		930,012		2,778,077	328,590
Issuance of common stock, net of issuance costs | $		$ 100,000							$ 300,000		$ 1,300,000		$ 6,600,000	$ 1,400,000	$ 9,400,000
Share price (in dollars per share) | $ / shares								$ 7.05
Shares issued (in shares)										110,642	810,012				810,012
Minimum | Lincoln Park [Member]
Class of Stock [Line Items]
Share price (in dollars per share) | $ / shares								$ 1.50
Maximum | Lincoln Park [Member]
Class of Stock [Line Items]
Value of shares issued | $								$ 1,000,000			$ 10,000,000
Shares sold in offering based on market price								36,666
Shares sold in offering (in shares)								30,000
LP 2020 Purchase Agreement [Member] | Lincoln Park [Member]
Class of Stock [Line Items]
New shares issued (in shares)	1,770,000		250,000
Value of shares issued | $			$ 10,000,000
Maximum percentage of shares issued			19.99%
Maximum number of shares issued			1,774,024
Beneficial Ownership Cap										4.99%
Shares sold in offering (in shares)									500,000
Issuance of common stock, net of issuance costs | $									$ 300,000
Share price (in dollars per share) | $ / shares			$ 0.7306
Shares issued (in shares)											0				0
Number of business days prior to purchase date | D			10
LP 2020 Purchase Agreement [Member] | Maximum | Lincoln Park [Member]
Class of Stock [Line Items]
Value of shares issued | $			$ 1,000,000
Shares sold in offering based on market price			50,000
LP 2020 Purchase Agreement [Member] | Closing Sale Price Above 1.00 [Member] | Maximum
Class of Stock [Line Items]
Shares sold in offering based on market price			80,000
LP 2020 Purchase Agreement [Member] | Closing Sale Price Above 1.50 [Member] | Maximum | Lincoln Park [Member]
Class of Stock [Line Items]
Shares sold in offering based on market price			100,000