SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Fair value of warrants (Details)	Jun. 21, 2019 shares	Dec. 31, 2019 Y $ / shares shares	Jun. 20, 2019 Y $ / shares shares
Class of Warrant or Right [Line Items]
Shares Offered During Period, New Issuance | shares	1,781,361
Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares	1,336,021	1,336,021	1,336,021
Series B Warrants [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares	1,116,320	3,132	1,116,320
Placement Agent Warrants [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares		142,509	142,509
Placement Agent Warrants [Member] | Maximum [Member]
Class of Warrant or Right [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares	142,509
Exercise price [Member] | Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input		1.50	3.72
Exercise price [Member] | Series B Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input		0.0001	3.72
Exercise price [Member] | Placement Agent Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input		3.38	3.38
Stock price [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input			2.80
Stock price [Member] | Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input		0.67	2.80
Stock price [Member] | Series B Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input		0.67	2.80
Stock price [Member] | Placement Agent Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input		0.67	2.80
Expected term [Member] | Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input | Y		3.47	4
Expected term [Member] | Series B Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input | Y		0.47	1.00
Expected term [Member] | Placement Agent Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input | Y		3.47	4
Risk-free interest rate [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input			1.77
Risk-free interest rate [Member] | Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input		1.64	1.77
Risk-free interest rate [Member] | Series B Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input		1.60	1.77
Risk-free interest rate [Member] | Placement Agent Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input		1.64	1.77
Expected volatility [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input			86
Expected volatility [Member] | Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input		123	86
Expected volatility [Member] | Series B Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input		123	86
Expected volatility [Member] | Placement Agent Warrants [Member]
Class of Warrant or Right [Line Items]
Warrants and Rights Outstanding, Measurement Input		123	86