Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 116,541	$ 175,688
Marketable securities	421,399	376,086
Accounts receivable	2,923	2,765
Prepaid expenses and other current assets	4,753	4,481
Total current assets	545,616	559,020
Operating lease right-of-use asset, net (note 5)	7,900	8,056
Property, plant and equipment, net	4,336	4,466
Deferred tax assets	207	465
Total assets	558,059	572,007
Current liabilities:
Accounts payable and accrued expenses (note 6)	7,982	13,717
Operating lease liability (note 5)	0	605
Total current liabilities	7,982	14,322
Operating lease liability, long-term (note 5)	8,224	7,652
Total liabilities	16,206	21,974
Shareholders’ equity:
Preferred shares, without par value; unlimited shares authorized; issued and outstanding: nil (December 31, 2021 - 1,016,000) (note 7)	0	7,732
Common shares, without par value; unlimited shares authorized; issued and outstanding: 53,059,049 (December 31, 2021 - 51,634,752) (note 7)	800,307	783,170
Additional paid-in capital	119,580	117,495
Accumulated deficit	(377,044)	(357,374)
Accumulated other comprehensive loss	(990)	(990)
Shareholders' equity	541,853	550,033
Total liabilities and shareholders’ equity	558,059	572,007
Commitments and contingencies (note 9)