RELATED PARTY TRANSACTIONS (Details) $ / shares in Units, $ in Thousands			1 Months Ended					3 Months Ended	12 Months Ended
	Dec. 22, 2019 shares	Mar. 01, 2019 shares	Jun. 30, 2019 USD ($)	Mar. 31, 2017 USD ($) shares	Jul. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Oct. 31, 2014 USD ($) ft²	Dec. 31, 2014	Dec. 31, 2019 USD ($) $ / shares	Dec. 31, 2018 USD ($) $ / shares	Dec. 31, 2017 USD ($)	Jan. 01, 2019 USD ($)	Apr. 30, 2018 USD ($)	Jul. 28, 2014 shares
Related Party Transaction [Line Items]
Common stock, par value (in dollars per share) | $ / shares									$ 0.001	$ 0.001
Shares issued | shares	5,434,783	4,100,000		769,230
Warrants to purchase | shares														1
Other research and development									$ 148,269	$ 149,793	$ 96,886
Operating Lease Liability									11,834
Right of use asset									$ 9,402	0
Collaboration Agreement [Member]
Related Party Transaction [Line Items]
Upfront Fee			$ 1,000			$ 1,000
Office Agreement [Member]
Related Party Transaction [Line Items]
Area of leases office space | ft²							24,000
Initial commitment period for office lease space							3 years
Upfront licensing fee paid					$ 1,000
Expenses incurred				$ 200
Percentage Of Occupancy							45.00%	45.00%	61.00%
Average Annual Rental Payments							$ 1,100
Operating Lease Initial Commitment Period							15 years
Long-term Line of Credit							$ 600
Additional collateral pledged													$ 600
Upfront Fee									$ 4,100	600
Operating Lease Liability												$ 9,300
Right of use asset												$ 7,700
Shared Services Agreement [Member]
Related Party Transaction [Line Items]
Costs and Expenses, Related Party									$ 900	$ 1,600	$ 1,200