Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred Shares	Common Shares	Treasury Stock	Additional Paid-in Capital	Accumulated Deficit
Balance at Dec. 31, 2018	$ 152,330	$ 21,850	$ 246,663	$ (10,413)	$ 1,282,762	$ (1,388,532)
Balance (in shares) at Dec. 31, 2018		289,317,460	329,110,863
Balance, Treasury Shares (in shares) at Dec. 31, 2018				(3,260,850)
Issuance of common stock, net of transaction costs	440,108		$ 15,879		424,229
Issuance of common stock, net of transaction costs (shares)			25,555,556
Issuance of common stock under employee stock purchase plan	2,165		$ 79		2,086
Issuance of common stock under employee stock purchase plan (in shares)			123,031
Issuance of common stock for milestone payment	6,216		$ 173		6,043
Issuance of common stock for milestone payment (in shares)			257,713
Exercise of stock options	24,478		$ 3,876		20,602
Exercise of stock options (in shares)			5,997,919
Vesting of restricted stock units	(25,487)		$ 2,503	$ (25,487)	(2,503)
Vesting of restricted stock units (in shares)			3,969,811	(1,650,142)
Stock-based compensation	31,098				31,098
Income (loss) for the period	(22,645)					(22,645)
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
Balance, Treasury Shares (in shares) at Dec. 31, 2019				(4,910,992)
Conversion of Series A Convertible Preferred Stock, net	(504)	$ (21,850)	$ 18,020		3,326
Conversion of Series A Convertible Preferred Stock, net (in shares)		(289,317,460)	28,931,746
Issuance of common stock under employee stock purchase plan	1,957		$ 225		1,732
Issuance of common stock under employee stock purchase plan (in shares)			347,153
Exercise of stock options	$ 5,158		$ 1,062		4,096
Exercise of stock options (in shares)	1,623,460		1,623,460
Vesting of restricted stock units	$ (15,182)		$ 1,635	$ (15,182)	(1,635)
Vesting of restricted stock units (in shares)			2,507,748	(975,927)
Stock-based compensation	45,813				45,813
Income (loss) for the period	(18,000)					(18,000)
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
Balance, Treasury Shares (in shares) at Dec. 31, 2020	5,886,919			(5,886,919)
Issuance of common stock under employee stock purchase plan	$ 1,650		$ 275		1,375
Issuance of common stock under employee stock purchase plan (in shares)			399,286
Exercise of stock options	$ 2,921		$ 827		2,094
Exercise of stock options (in shares)	1,203,845		1,203,845
Vesting of restricted stock units	$ (9,644)		$ 2,810	$ (9,644)	(2,810)
Vesting of restricted stock units (in shares)			4,056,644	(1,599,848)
Stock-based compensation	36,938				36,938
Income (loss) for the period	7,729					7,729
Balance at Dec. 31, 2021	$ 667,099		$ 294,027	$ (60,726)	$ 1,855,246	$ (1,421,448)
Balance (in shares) at Dec. 31, 2021			404,084,775
Balance, Treasury Shares (in shares) at Dec. 31, 2021	7,486,767			(7,486,767)