Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Operating activities:
Net loss	$ (16,514)	$ (30,219)
Items not involving cash:
Depreciation	442	283
Amortization of discount on term loan	216	388
Deferred income tax recovery	(240)	(73)
Stock-based compensation	4,067	1,567
Unrealized foreign exchange gain	(451)	(161)
Unrealized gain on marketable securities	(228)	(134)
Loss on repayment of term loan (note 9)	988
Changes in operating assets and liabilities:
Accounts receivable	(827)	(54)
Prepaid expenses and other current assets	421	208
Accounts payable and accrued expenses	122	3,694
Deferred revenue	(23,006)
Net cash used in operating activities	(35,010)	(24,501)
Investing activities:
Purchases of property, plant and equipment	(1,809)	(645)
Purchases of marketable securities	(213,560)	(76,064)
Proceeds from marketable securities	155,346	70,818
Net cash used in investing activities	(60,023)	(5,891)
Financing activities:
Repayment of term loan and repayment fees (note 9)	(16,743)
Issuance of common shares, net of issuance costs (note 10a)	102,456
Issuance of common shares pursuant to exercise of stock options	37	87
Net cash provided by financing activities	85,750	87
Effect of exchange rate changes on cash and cash equivalents	(372)	222
Decrease in cash and cash equivalents	(9,655)	(30,083)
Cash and cash equivalents, beginning of period	24,755	67,754	$ 67,754
Cash and cash equivalents, end of period	15,100	37,671	$ 24,755
Supplemental disclosures:
Interest paid	339	702
Interest received	3,058	1,938
Cash paid for operating lease	469	469
Supplemental disclosures of non-cash transactions:
Fair value of stock options exercised on a cashless basis	$ 878	$ 354