WARRANT DERIVATIVE LIABILITY - Assumptions Used to Calculate Fair Value of 2019 Warrants (Details) - 2019 Warrants	Mar. 31, 2021 item Y	Dec. 31, 2020 Y item	May 31, 2019 item Y
Number of shares underlying the warrants
WARRANT DERIVATIVE LIABILITY
Measurement input used to calculate fair value of warrants	322,807	1,645,807	3,000,000
Current stock price
WARRANT DERIVATIVE LIABILITY
Measurement input used to calculate fair value of warrants	0.92	0.48	0.95
Exercise price
WARRANT DERIVATIVE LIABILITY
Measurement input used to calculate fair value of warrants	0.40	0.40	1.30
Expected volatility
WARRANT DERIVATIVE LIABILITY
Measurement input used to calculate fair value of warrants	110	108	133
Risk-free interest rate
WARRANT DERIVATIVE LIABILITY
Measurement input used to calculate fair value of warrants	0.92	0.36	1.93
Expected term (in years)
WARRANT DERIVATIVE LIABILITY
Measurement input used to calculate fair value of warrants | Y	3.16	3.41	5.00