COMMITMENTS AND CONTINGENCIES - Narrative (Details) - USD ($)				3 Months Ended	12 Months Ended			20 Months Ended
	Nov. 12, 2018	Dec. 15, 2017	Nov. 06, 2017	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Apr. 17, 2019
Other Commitments [Line Items]
Purchase commitments					$ 2,000,000			$ 2,000,000
Severance and related expense				$ 700,000	0	$ 741,000	$ 1,524,000
Operational cash outflows					18,475,000	20,881,000	$ 3,704,000
Chief Financial Officer
Other Commitments [Line Items]
Severance and related expense	$ 624,000
Operational cash outflows					532,000
Chief Commercialization Officer
Other Commitments [Line Items]
Severance and related expense			$ 582,000
Operational cash outflows						397,000
Chief Executive Officer
Other Commitments [Line Items]
Severance and related expense		$ 767,000
Operational cash outflows						$ 670,000
Pending Litigation | Unfavorable Regulatory Action
Other Commitments [Line Items]
Cost accrued					820,000			820,000	$ 500,000
Increase in loss contingency accrual								500,000
Total loss contingency accrued					$ 1,000,000			1,000,000
Largest Customer | Sales | Customer Concentration Risk
Other Commitments [Line Items]
Concentration receivable risk					11.00%
China joint venture
Other Commitments [Line Items]
Capital contribution					$ 400,000			$ 400,000