COMMITMENTS AND CONTINGENCIES - Narrative (Details) € in Thousands			1 Months Ended	12 Months Ended
	Dec. 31, 2019 EUR (€)	Dec. 31, 2019 USD ($) arrangement	Oct. 31, 2010 USD ($)	Dec. 31, 2019 USD ($) arrangement renewal_term	Dec. 31, 2018 USD ($)
Commitments and Contingencies [Line Items]
License fee expense				$ 100,000	$ 700,000
Number of renewal terms (up to) | renewal_term				2
Renewal term		3 years		3 years
Rent expense					300,000
Rent expense				$ 300,000
Operating expenses of leases				300,000	300,000
Future annual minimum payment 2020		$ 300,000		$ 300,000
Yale University
Commitments and Contingencies [Line Items]
Term of agreement				5 years
Proceeds from collaboration				$ 900,000
University of Texas
Commitments and Contingencies [Line Items]
Number of arrangements | arrangement		1		1
Nonrefundable upfront license documentation fee				$ 10,000
Annual license maintenance fee				10,000
Potential milestone payment for initiation of defined clinical trials (up to)		$ 600,000		600,000
License fee expense				0	100,000
University of Texas | United States
Commitments and Contingencies [Line Items]
Potential milestone payment for regulatory approval (up to)		2,000,000		2,000,000
University of Texas | Other Regions
Commitments and Contingencies [Line Items]
Potential milestone payment for regulatory approval (up to)		500,000		500,000
RICC
Commitments and Contingencies [Line Items]
Potential future milestone payments per licensed product (up to)		5,200,000.0		5,200,000.0
Payments for raw materials				0	$ 300,000
t2cure
Commitments and Contingencies [Line Items]
Nonrefundable upfront license documentation fee			$ 46,000
Annual license maintenance fee	€ 3	3,000
Potential milestone payment for initiation of defined clinical trials (up to)		700,000		$ 700,000
Term of agreement				10 years
Period to terminate agreement				60 days
t2cure | United States
Commitments and Contingencies [Line Items]
Potential milestone payment for regulatory approval (up to)		2,500,000		$ 2,500,000
t2cure | European Union or Japan
Commitments and Contingencies [Line Items]
Potential milestone payment for regulatory approval (up to)		$ 1,500,000.0		$ 1,500,000.0
Minimum
Commitments and Contingencies [Line Items]
Resignation for good reason term				1 month
Change on control term				1 month
Maximum
Commitments and Contingencies [Line Items]
Term of employee's base salary				12 months
Term of executive’s outstanding unvested stock options				12 months
Term of employee health coverage				12 months
Resignation for good reason term				12 months
Change on control term				12 months
Chief Executive Officer
Commitments and Contingencies [Line Items]
Term of employee health coverage				12 months
Total compensation due to change in control, in base salary term				24 months