NOTE PAYABLE - Narrative (Details) - USD ($)				8 Months Ended	12 Months Ended		29 Months Ended
	Sep. 03, 2019	Jun. 02, 2018	Feb. 18, 2016	Jul. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Jul. 31, 2018
Debt Instrument [Line Items]
Facility fees					$ 0	$ 50,000
Payments of principal of note payable	$ (2,600,000)				$ (4,808,000)	$ (1,282,000)
Payment of associated accrued interest and aggregate end-of-term payment	$ 600,000
Note Payable
Debt Instrument [Line Items]
Face amount			$ 7,500,000
End of term payment rate			4.50%
Applicable percent of aggregate unfunded term loan commitments			50.00%
Increase in termination payment				$ 100,000
Facility fees							$ 200,000
Interest Rate Option 1 | Note Payable
Debt Instrument [Line Items]
Stated rate			9.20%
Interest Rate Option 2 | Note Payable
Debt Instrument [Line Items]
Stated rate			9.20%
Interest Rate Option 2 | Note Payable | Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate			3.50%
Hercules Capital Warrants
Debt Instrument [Line Items]
Warrants converted (in shares)		9,005
Exercise price (in usd per share)		$ 33.31
Warrant liability		$ 300,000