EQUITY, SHARE-BASED COMPENSATION, WARRANTS AND FINANCING TRANSACTIONS, Warrants (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended		3 Months Ended										9 Months Ended		12 Months Ended
		Oct. 31, 2019		Sep. 30, 2019		Jun. 30, 2019		Mar. 31, 2019		Sep. 30, 2018		Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019		Dec. 31, 2018		Dec. 31, 2017	Mar. 08, 2019
Equity and Liability Warrants, Additional Disclosures [Abstract]
Fair value of exercise price (in dollars per share)																			$ 0.01
Warrant [Member]
Shares Under Warrants [Roll Forward]
Outstanding at beginning of period (in shares)		7,712,225	[1],[2]	7,712,225	[2]	8,702,100	[2]	10,252,714	[2]	15,546,197		19,644,274	21,157,273	10,252,714	[2]	21,157,273
Issued (in shares)	[3]							0	[2]				315,000
Cash exercised (in shares)				0	[2]	0	[2]	(600,000)	[2]	(2,660,000)		(4,092,077)	(1,827,999)
Cashless exercised (in shares)	[4]			0	[2]					(300,000)
Impact of warrant modification, After modification (in shares)	[5]			0	[2]					600,000
Impact of warrant modification, Prior to modification (in shares)	[5]			0	[2]					(850,000)
Expired (in shares)				0	[2]	(989,875)	[2]	(950,614)	[2]	(2,573)		(6,000)	0
Outstanding at end of period (in shares)				7,712,225	[1],[2]	7,712,225	[2]	8,702,100	[2]	12,333,624	[1]	15,546,197	19,644,274	7,712,225	[1],[2]	10,252,714	[2]	21,157,273
Equity and Liability Warrants Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding at beginning of period (in dollars per share)		$ 1.37	[1]	$ 1.37		$ 1.85		$ 2.25		$ 2.86		$ 2.47	$ 2.30	$ 2.25		$ 2.30
Issued (in dollars per share)	[3]												4.73
Cash exercised (in dollars per share)								3.30		2.00		0.96	0.96
Cashless exercised (in dollars per share)	[4]									1.60
Impact of warrant modification, After to Modification (in dollars per share)	[5]									3.30
Impact of warrant modification, Prior to Modification (in dollars per share)	[5]									5.27
Expired (in dollars per share)						5.60		5.25		16.00		16.80
Outstanding at end of period (in dollars per share)				$ 1.37	[1]	$ 1.37		$ 1.85		$ 2.93	[1]	$ 2.86	$ 2.47	$ 1.37	[1]	$ 2.25		$ 2.30
Equity and Liability Warrants, Additional Disclosures [Abstract]
Outstanding, weighted average remaining contractual life				2 years 2 months 12 days	[1]	2 years 4 months 24 days		2 years 4 months 24 days		2 years 2 months 12 days	[1]	2 years 6 months	3 years			2 years 3 months 18 days		3 years 4 months 24 days
Issued	[3]												2 years 4 months 24 days
Cash exercised										3 years		3 years 8 months 12 days	4 years 1 month 6 days
Cashless exercised	[4]									1 year 9 months 18 days
Impact of warrant modification, After modification	[5]									7 months 6 days
Impact of warrant modification, Prior to modification	[5]									1 year 7 months 6 days
Expense recognized for the issuances												$ 0.1
Issuance of common stock upon cashless exercise of warrants (in shares)														139,392
Fair value of exercise price (in dollars per share)				$ 2.63										$ 2.63
Warrant [Member] | $0.96 [Member]
Shares Under Warrants [Roll Forward]
Cashless exercised (in shares)														3,774,344
Equity and Liability Warrants Outstanding, Weighted Average Exercise Price [Roll Forward]
Cashless exercised (in dollars per share)														$ 0.96
Warrant [Member] | $0.96 [Member] | Subsequent Events [Member]
Shares Under Warrants [Roll Forward]
Cash exercised (in shares)		(85,409)
Equity and Liability Warrants Outstanding, Weighted Average Exercise Price [Roll Forward]
Cash exercised (in dollars per share)		$ 0.96
Warrant [Member] | $5.25 [Member]
Shares Under Warrants [Roll Forward]
Cashless exercised (in shares)														384,536
Equity and Liability Warrants Outstanding, Weighted Average Exercise Price [Roll Forward]
Cashless exercised (in dollars per share)														$ 5.25
Warrant [Member] | $5.27 [Member] | Subsequent Events [Member]
Equity and Liability Warrants, Additional Disclosures [Abstract]
Warrants expired (in shares)		(94,536)
Warrants expired, exercise price (in dollars per share)		$ 5.27

[1] In October 2019, warrants for the purchase of up to 94,536 shares of common stock at an exercise price of $5.27 per share expired and warrants for the purchase of up to 85,409 shares of common stock at an exercise price of $0.96 per share were cash exercised.

[2] Under the terms of certain outstanding warrants, the holders may elect to exercise the warrants under a cashless exercise feature. As of September 30, 2019, warrant holders may elect to exercise cashless warrants for 3,774,344 shares of common stock at an exercise price of $0.96 per share and 384,536 shares of common stock at an average exercise price of $5.25 per share. If we register for resale the shares subject to warrants, the holders of some of the warrants may no longer have the right to elect a cashless exercise. If we fail to maintain a registration statement for the resale of shares under certain other warrants, the shares under those warrants may again become exercisable using a cashless exercise feature.

[3] We recognized $0.1 million of expense for these warrant issuances in the three months ended June 30, 2018.

[4] We issued 139,392 shares of common stock upon cashless exercise of these warrants, based on the fair value at the date of exercise of $2.63 per share.

[5] The fair value of the warrants immediately before the modification equaled the fair value of the warrants immediately after the modification and, therefore, no gain or loss was recorded.