STRATEGIC ALLIANCE AND COLLABORATION WITH SERVIER - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended		20 Months Ended
	Feb. 28, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Jan. 01, 2019
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		$ 828,000	$ 372,000
Amounts incurred but not yet billed		1,000		$ 300,000
Accounts receivable		4,000		108,000
Servier
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable		0
Research and development reimbursable costs
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue		$ 700,000	$ 300,000
Servier Collaboration Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum reimbursements of development costs					$ 3,100,000
Incremental increase in amount	$ 1,000,000
Development and regulatory milestones					$ 60,400,000
Servier Collaboration Agreement | Milestone payments
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenue				$ 7,500,000