LICENSE AGREEMENTS AND COMMITMENTS - Lease agreements (Details) $ in Thousands	1 Months Ended
	Aug. 31, 2020 USD ($)	Feb. 28, 2019 USD ($) ft²	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 ft²	Feb. 28, 2018	Jan. 31, 2018 USD ($)
Leases
Operating lease right-of-use assets			$ 3,398	$ 4,569
Lease liabilities			$ 3,002	$ 3,979
Manufacturing facility, Indiana
Leases
Lease term	2 years
Operating lease right-of-use assets	$ 3,617
Lease liabilities	2,679
Difference between right of use asset and lease liability recognized	938
Access fee monthly installment	117
Amount of additional access fees to be paid in monthly installments	$ 1,631
Option to extend	false
Laboratory, New Jersey
Leases
Leased area (in square feet) | ft²		4,548
Additional leased area (in square feet) | ft²					235
Lease term		3 years
Option to extend		true
Option to extend, period		2 years
Fixed rent payable per annum		$ 144
Lease payable per month		12
Corporate headquarters, New York
Leases
Lease term							5 years
Fixed rent payable per annum							$ 384
Lease payable per month							$ 32
Office space, Denmark
Leases
Lease term						3 years
Lease payable per month		$ 19