SIGNIFICANT ACCOUNTING POLICIES - Property, plant and equipment (Details)	12 Months Ended
	Dec. 31, 2017
Building
PROPERTY, PLANT AND EQUIPMENT
Depreciation rate declining balance	4.00%
Production & development equipment
PROPERTY, PLANT AND EQUIPMENT
Depreciation rate declining balance	30.00%
Computer hardware
PROPERTY, PLANT AND EQUIPMENT
Depreciation rate declining balance	30.00%
Computer software
PROPERTY, PLANT AND EQUIPMENT
Depreciation rate declining balance	100.00%
Office equipment
PROPERTY, PLANT AND EQUIPMENT
Depreciation rate declining balance	20.00%