COMMITMENTS AND CONTINGENCIES, LEASES (Details)			3 Months Ended		9 Months Ended
	May 03, 2018 USD ($) ft²	Oct. 31, 2017 USD ($) ft² item	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)	Nov. 01, 2018 USD ($)	Jun. 19, 2017 USD ($)	Jun. 13, 2017 ft²
Lessee, Lease, Description [Line Items]
Deferred rent removed and gain on lease assignment					$ 603,000
Loss on impairment of fixed assets					48,000
Prepaid rent						$ 17,000
Operating leases, rent expense, net			$ 107,000		746,000
Moderna Sublease
Lessee, Lease, Description [Line Items]
Sublease income recorded as offset to rent expense			$ 0		112,000
Cambridge Lease
Lessee, Lease, Description [Line Items]
Lease space (in square feet) | ft²		26,342
Term of commercial lease		6 years 3 months
Number of options to extend lease | item		1
Term of lease extension option		5 years					5 years
Standby letter of credit		$ 311,000
Letter of credit terminated amount	$ 311,000
Deferred rent removed and gain on lease assignment				$ 603,000
Loss on impairment of fixed assets					$ 48,000
Cambridge Lease | Moderna Sublease
Lessee, Lease, Description [Line Items]
Lease space (in square feet) | ft²									5,233
Tenant security deposit								$ 55,000
Cambridge Lease | Third Party Lease
Lessee, Lease, Description [Line Items]
Lease space (in square feet) | ft²	5,104
Standby letter of credit	$ 40,000						$ 60,000
Tenant security deposit				$ 55,000