LICENSE AGREEMENTS AND COMMITMENTS - Other agreements (Details) $ in Thousands							3 Months Ended		6 Months Ended
	Oct. 01, 2018 individual	Nov. 13, 2017	Jun. 27, 2017 agreement	Jun. 21, 2017	Mar. 20, 2016 individual	Nov. 05, 2015	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)
Agreements
Research and development							$ 14,494	$ 8,293	$ 27,005	$ 14,497
SRA
Agreements
Research service period						5 years
Research and development							306	297	612	594
MDSA
Agreements
Research and development							171	107	342	213
CTA
Agreements
Research service period				5 years
Research and development							1,281	511	2,134	2,142
CFAs
Agreements
Number of core facility service agreements | agreement			2
Research and development							269	81	488	195
CD33-SRA
Agreements
Research service period		2 years
Research and development							$ 174	$ 167	$ 347	$ 334
Researchers, Employees of MSK | MDSA
Agreements
Number of individuals | individual	5				2