WARRANTS - Schedule of Warrant Activity (Details) - $ / shares		1 Months Ended		12 Months Ended
	Sep. 28, 2020	Aug. 31, 2020	Jun. 30, 2018	Dec. 31, 2020	Dec. 31, 2019
Private Placement Warrants - September 2017
Roll forward of warrant activity
Warrant exercised/expired (in shares)	(1,961,000)		(10,600)
Cancellation of warrants (in shares)		5,319
Common stock warrants
Roll forward of warrant activity
Balance at the beginning of the period (in shares)				2,134,362	3,385,100
Warrant exercised/expired (in shares)				(2,134,362)	(1,250,738)
Balance at the end of the period (in shares)				0	2,134,362
Common stock warrants | Consulting Warrant
Warrant liabilities
Exercise price (in dollars per share)					$ 0.01
Roll forward of warrant activity
Balance at the beginning of the period (in shares)				6,667	6,667
Warrant exercised/expired (in shares)				(6,667)	0
Balance at the end of the period (in shares)				0	6,667
Exercise of warrants, cashless (in shares)				6,640
Common stock warrants | Consulting Warrant | Cashless
Roll forward of warrant activity
Warrant exercised/expired (in shares)				(6,667)
Common stock warrants | Financing Warrants
Warrant liabilities
Exercise price (in dollars per share)					$ 3.35
Roll forward of warrant activity
Balance at the beginning of the period (in shares)				62,530	62,530
Warrant exercised/expired (in shares)				(62,530)	0
Balance at the end of the period (in shares)				0	62,530
Expiration of warrants (in shares)				62,530
Common stock warrants | Underwriting Warrant
Warrant liabilities
Exercise price (in dollars per share)					$ 7.50
Roll forward of warrant activity
Balance at the beginning of the period (in shares)				0	310,500
Warrant exercised/expired (in shares)					(310,500)
Balance at the end of the period (in shares)					0
Common stock warrants | Private Placement Warrants - 2016
Warrant liabilities
Exercise price (in dollars per share)					$ 2.86
Roll forward of warrant activity
Balance at the beginning of the period (in shares)				0	818,063
Warrant exercised/expired (in shares)					(818,063)
Balance at the end of the period (in shares)					0
Exercise of warrants, cashless (in shares)					1,809
Expiration of warrants (in shares)					288,135
Exercises of warrants, cashless (in shares)					485,000
Stock issued during period shares warrants exercised, cashless exercise					44,928
Common stock warrants | Private Placement Warrants - 2016 | Cash
Roll forward of warrant activity
Stock issued during period shares warrants exercised, cashless exercise					335,000
Common stock warrants | Underwriting Warrants - Public Offering 2016
Warrant liabilities
Exercise price (in dollars per share)					$ 4.25
Roll forward of warrant activity
Balance at the beginning of the period (in shares)				0	122,175
Warrant exercised/expired (in shares)					(122,175)
Balance at the end of the period (in shares)					0
Common stock warrants | Private Placement Warrants - September 2017
Warrant liabilities
Exercise price (in dollars per share)					$ 4.85
Roll forward of warrant activity
Balance at the beginning of the period (in shares)				1,966,319	1,966,319
Warrant exercised/expired (in shares)				(1,966,319)	0
Balance at the end of the period (in shares)				0	1,966,319
Expiration of warrants (in shares)				1,961,000
Cancellation of warrants (in shares)				5,319
Common stock warrants | Placement Agent Warrants - 2017
Warrant liabilities
Exercise price (in dollars per share)					$ 4.85
Roll forward of warrant activity
Balance at the beginning of the period (in shares)				98,846	98,846
Warrant exercised/expired (in shares)				(98,846)	0
Balance at the end of the period (in shares)				0	98,846
Expiration of warrants (in shares)				98,846