Condensed Consolidated Statement of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred Shares	Common Shares	Treasury Stock	Additional Paid-in Capital	Accumulated Deficit
Balance at Dec. 31, 2019	$ 608,263	$ 21,850	$ 269,173	$ (35,900)	$ 1,764,317	$ (1,411,177)
Balance (in shares) at Dec. 31, 2019		289,317,460	365,014,893	(4,910,992)
Exercise of stock options	$ 1,306		$ 269		1,037
Exercise of stock options (in shares)	412,465		412,465
Vesting of restricted stock units	$ (13,831)		$ 1,274	$ (13,831)	(1,274)
Vesting of restricted stock units (in shares)			1,951,448	(759,832)
Stock-based compensation	10,591				10,591
Loss for the period	(20,553)					(20,553)
Balance at Mar. 31, 2020	585,776	$ 21,850	$ 270,716	$ (49,731)	1,774,671	(1,431,730)
Balance (in shares) at Mar. 31, 2020		289,317,460	367,378,806	(5,670,824)
Balance at Dec. 31, 2020	627,505		$ 290,115	$ (51,082)	1,817,649	(1,429,177)
Balance (in shares) at Dec. 31, 2020			398,425,000	(5,886,919)
Exercise of stock options	$ 2,059		$ 536		1,523
Exercise of stock options (in shares)	783,320		783,320
Vesting of restricted stock units	$ (7,252)		$ 1,709	$ (7,252)	(1,709)
Vesting of restricted stock units (in shares)			2,447,405	(1,003,965)
Stock-based compensation	13,925				13,925
Loss for the period	(1,626)					(1,626)
Balance at Mar. 31, 2021	$ 634,611		$ 292,360	$ (58,334)	$ 1,831,388	$ (1,430,803)
Balance (in shares) at Mar. 31, 2021			401,655,725	(6,890,884)