Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 87,985	$ 45,009
Marketable securities	186,718	131,988
Accounts receivable	5,060	1,822
Prepaid expenses and other current assets	3,497	2,964
Total current assets	283,260	181,783
Operating lease right-of-use asset, net (note 6)	3,206	3,326
Property, plant and equipment, net	3,691	3,554
Deferred tax assets (note 11)	514	523
Total assets	290,671	189,186
Current liabilities:
Accounts payable and accrued expenses (note 7)	7,580	10,874
Deferred revenue (note 10)	3,642	3,642
Operating lease liability (note 6)	270	265
Total current liabilities	11,492	14,781
Operating lease liability, long-term (note 6)	2,902	3,050
Total liabilities	14,394	17,831
Shareholders’ equity:
Preferred shares, without par value; unlimited shares authorized; issued and outstanding: 1,016,000 (December 31, 2020 - 1,016,000) (note 9)	7,732	7,732
Common shares, without par value; unlimited shares authorized; issued and outstanding: 40,962,715 (December 31, 2020 - 35,012,125) (note 9)	498,334	397,748
Additional paid-in capital	65,457	45,357
Accumulated deficit	(294,256)	(278,492)
Accumulated other comprehensive loss	(990)	(990)
Shareholders' equity	276,277	171,355
Total liabilities and shareholders’ equity	290,671	189,186
Commitments and contingencies (note 12)