7. FINANCIAL INSTRUMENTS - Unrealized losses and fair value (Details) $ in Thousands	Mar. 31, 2020 USD ($)
Fair Value
Less Than 12 Months, Fair Value	$ 2,498
Total, Fair Value	2,498
Unrealized Loss
Less Than 12 Months, Unrealized Loss	2
Total, Unrealized Loss	2
Certificates of deposit
Fair Value
Less Than 12 Months, Fair Value	2,498
Total, Fair Value	2,498
Unrealized Loss
Less Than 12 Months, Unrealized Loss	2
Total, Unrealized Loss	$ 2