INCOME TAXES - Schedule of Credit Carryforwards (Details) $ in Millions	Dec. 31, 2019 USD ($)
United States | Federal
Income Taxes [Line Items]
NOL carryforwards	$ 118.9
United States | State
Income Taxes [Line Items]
NOL carryforwards	131.2
Indefinite | United States | Federal
Income Taxes [Line Items]
NOL carryforwards	41.2
R&D credit carryforwards | United States | Federal
Income Taxes [Line Items]
Tax credit carryforwards	2.2
R&D credit carryforwards | United States | State
Income Taxes [Line Items]
Tax credit carryforwards	0.9
R&D credit carryforwards | Canada
Income Taxes [Line Items]
Tax credit carryforwards	6.2
Non-capital loss carryforwards | Canada
Income Taxes [Line Items]
Tax credit carryforwards	32.6
Investment tax credit carryforwards | Canada
Income Taxes [Line Items]
Tax credit carryforwards	$ 1.5