Condensed Consolidated Statements of Changes in Stockholders' (Deficit) Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2018	$ 84	$ 552,531	$ (234)	$ (528,345)	$ 24,036
Balance (in shares) at Dec. 31, 2018	83,911,855		41,309
Issuance of restricted stock	$ 1	(1)
Issuance of restricted stock (in shares)	1,851,520
Warrants issued with debt financing		993			993
Forfeiture of restricted stock (in shares)	(116,463)
Offering costs paid					200
Issuance of common stock in public offering	$ 10	77,465			77,475
Issuance of common stock in public offering (in shares)	10,149,783
Issuance of common stock in At-the-Market offerings (net of offering costs)	$ 14	97,533			97,547
Issuance of common stock in At-the-Market offerings (net of offering costs) (in shares)	13,620,165
Compensation in respect of restricted stock granted to employees, directors and consultants		11,335			11,335
Shares issued in connection with in-licensing agreements		100			100
Shares issued in connection with in-licensing agreements (in shares)	8,383
Net loss				(172,871)	(172,871)
Balance at Dec. 31, 2019	$ 109	739,956	$ (234)	(701,216)	38,615
Balance (in shares) at Dec. 31, 2019	109,425,243		41,309
Issuance of common stock in connection with exercise of options		146			$ 146
Issuance of common stock in connection with exercise of options	35,814				35,814
Issuance of restricted stock	$ 5	(5)
Issuance of restricted stock (in shares)	4,909,829
Forfeiture of restricted stock (in shares)	(128,666)
Offering costs paid					$ 29,900
Issuance of common stock in public offering	$ 17	462,212			462,229
Issuance of common stock in public offering (in shares)	17,043,000
Issuance of common stock in At-the-Market offerings (net of offering costs)	$ 10	217,442			217,452
Issuance of common stock in At-the-Market offerings (net of offering costs) (in shares)	9,332,386
Compensation in respect of restricted stock granted to employees, directors and consultants		80,289			80,289
Net loss				(279,381)	(279,381)
Balance at Dec. 31, 2020	$ 141	1,500,040	$ (234)	(980,597)	519,350
Balance (in shares) at Dec. 31, 2020	140,617,606		41,309
Issuance of common stock in connection with exercise of options		216			$ 216
Issuance of common stock in connection with exercise of options	52,694				52,694
Issuance of restricted stock	$ 2	(2)
Issuance of restricted stock (in shares)	2,738,974
Warrants issued with debt financing		2,195			$ 2,195
Forfeiture of restricted stock (in shares)	(189,231)
Offering costs paid		(204)			(204)
Issuance of common stock in At-the-Market offerings (net of offering costs)		2,423			2,423
Issuance of common stock in At-the-Market offerings (net of offering costs) (in shares)	72,000
Compensation in respect of restricted stock granted to employees, directors and consultants		61,274			61,274
Net loss				(348,101)	(348,101)
Balance at Dec. 31, 2021	$ 143	$ 1,565,942	$ (234)	$ (1,328,698)	$ 237,153
Balance (in shares) at Dec. 31, 2021	143,292,043		41,309