INCOME TAXES, CARRYFORWARDS (Details) $ in Millions	Dec. 31, 2019 USD ($)
U.S. federal
Net operating loss carryforwards
Net operating loss carryforwards	$ 140.0
U.S. federal | Expiring beginning in 2026
Net operating loss carryforwards
Net operating loss carryforwards	117.3
U.S. federal | Never expiring
Net operating loss carryforwards
Net operating loss carryforwards	22.8
Massachusetts
Net operating loss carryforwards
Net operating loss carryforwards	$ 131.9