Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities:
Net loss	$ (15,764)	$ (7,484)
Items not involving cash:
Depreciation	196	104
Amortization of discount on term loan		137
Deferred income tax expense	9	52
Stock-based compensation	1,965	1,015
Unrealized foreign exchange (gain) loss	(204)	522
Unrealized (gain) loss on marketable securities	74	(281)
Changes in operating assets and liabilities:
Accounts receivable	(3,238)	(824)
Prepaid expenses and other current assets	(533)	113
Accounts payable and accrued expenses	(3,213)	(577)
Deferred revenue		(5,844)
Net cash used in operating activities	(20,708)	(13,067)
Investing activities:
Purchases of property, plant and equipment	(404)	(647)
Purchases of marketable securities	(100,655)	(107,482)
Proceeds from marketable securities	45,955	55,204
Net cash used in investing activities	(55,104)	(52,925)
Financing activities:
Proceeds from issuance of common shares and pre-funded warrants, net of issuance costs (note 9a)	118,615	102,456
Issuance of common shares pursuant to exercise of stock options	106	14
Net cash provided by financing activities	118,721	102,470
Effect of exchange rate changes on cash and cash equivalents	67	(725)
Increase in cash and cash equivalents	42,976	35,753
Cash and cash equivalents, beginning of period	45,009	24,755
Cash and cash equivalents, end of period	87,985	60,508
Supplemental disclosures:
Interest paid		206
Interest received	651	1,172
Cash paid for operating lease	202	159
Supplemental disclosures of non-cash transactions:
Fair value of stock options exercised on a cashless basis	$ 448	$ 583