FAIR VALUE MEASUREMENT OF FINANCIAL INSTRUMENTS - Quantitative Information about Level 3 Unobservable Inputs (Details) - Level 3	Sep. 30, 2019 USD ($)
Monte Carlo simulation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Valuation Technique	$ 6,000,000
Monte Carlo simulation | Discount rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.028
Monte Carlo simulation | Revenue Volatility
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.244
Monte Carlo simulation | Risk free rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.019
Probability Analysis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Valuation Technique	$ 12,373,000
Probability Analysis | Discount rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.030
Probability Analysis | Payment amounts | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	$ 3,000,000
Probability Analysis | Payment amounts | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	7,000,000
Probability Analysis | Payment amounts | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	$ 4,800,000
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	0.54
Probability Analysis | Probabilities | Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Input	0.47