STOCKHOLDERS' EQUITY (DEFICIT) - Summary of warrant activity (Details)	3 Months Ended
	Mar. 31, 2020 $ / shares shares
Weighted- Average Exercise Price
Outstanding beginning balance (in dollars per share) | $ / shares	$ 3.83
Forfeited or expired (in dollars per share) | $ / shares	2.81
Outstanding ending balance (in dollars per share) | $ / shares	$ 4.50
Warrant
Warrants
Outstanding beginning balance (in shares) | shares	2,754,062
Forfeited or expired (in shares) | shares	(174,642)
Outstanding ending balance (in shares) | shares	2,579,420