FAIR VALUE MEASUREMENT OF FINANCIAL INSTRUMENTS - Quantitative Information about Level 3 Unobservable Inputs (Details) - Level 3 $ in Thousands	Sep. 30, 2020 USD ($)
Monte Carlo simulation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 1,000
Monte Carlo simulation | Discount rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.016
Monte Carlo simulation | Revenue Volatility
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.462
Monte Carlo simulation | Risk free rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.012
Probability Analysis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 8,123
Probability Analysis | Discount rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.010
Probability Analysis | Payment amounts | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	$ 5,250
Probability Analysis | Payment amounts | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	7,000
Probability Analysis | Payment amounts | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	$ 6,400
Probability Analysis | Probabilities | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.40
Probability Analysis | Probabilities | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.60
Probability Analysis | Probabilities | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.53