DEBT (Details)			3 Months Ended		6 Months Ended
	Apr. 14, 2020 USD ($)	Dec. 21, 2017 USD ($) installment	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)
Line of Credit Facility [Line Items]
Payment on debt					$ 10,000,000	$ 0
Amortization of deferred issuance costs					388,000	439,000
Oxford Loan
Line of Credit Facility [Line Items]
Borrowings		$ 35,000,000.0
Number of periodic payments | installment		35
Final payment, percent of principal		8.70%
Early repayment fee, percentage of prepaid amount, period one		3.00%
Early repayment fee, percentage of prepaid amount, period two		2.00%
Early repayment fee, percentage of prepaid amount, period three		1.00%
Payment on debt	$ 7,000,000.0
Partial payment of final payment percentage	$ 600,000
Payment of debt issuance costs		$ 100,000
Final facility charge payment		$ 3,000,000.0
Amortization of deferred issuance costs			$ 200,000	$ 200,000	$ 400,000	$ 400,000
Interest rate at end of period			10.98%		10.98%
Oxford Loan | Floating per Annum Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate - plus (minus)		7.25%
Oxford Loan | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on variable rate - plus (minus)		1.25%
Hercules Loan
Line of Credit Facility [Line Items]
Payment on debt		$ 32,900,000