Condensed Consolidated Statements of Stockholders’ Equity (Unaudited) - USD ($)	Total	Additional Paid-in Capital [Member]	Common Stock [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]
Balance Beginning	$ 66,993,000	$ 422,017,000	$ 73,000	$ (234,000)	$ 354,863,000
Balance beginning			73,181,750	41,309
Balance beginning at Dec. 31, 2017			73,181,750	41,309
Balance Ending at Mar. 31, 2018			77,134,683	41,309
Issuance of restricted stock (in shares)			87,500
Forfeiture of restricted stock (in shares)			(123,911)
Issuance of common stock in At-the-Market offerings			3,989,344
Balance Beginning at Dec. 31, 2017	66,993,000	422,017,000	$ 73,000	$ (234,000)	354,863,000
Balance Beginning	66,993,000	422,017,000	73,000	$ (234,000)	354,863,000
Issuance of common stock in At-the-Market offerings	52,430,000	52,426,000	$ 4,000
Compensation in respect of restricted stock granted to employees, directors and consultants	7,337,000	7,337,000
Balance beginning			73,181,750	41,309
Balance Ending at Mar. 31, 2018	85,232,000	481,781,000	$ 77,000	$ (234,000)	(396,392,000)
Net loss	(41,529,000)				(41,529,000)
Balance beginning at Dec. 31, 2017			73,181,750	41,309
Balance Ending at Jun. 30, 2018			82,539,417	41,309
Balance Beginning at Dec. 31, 2017	66,993,000	422,017,000	$ 73,000	$ (234,000)	354,863,000
Balance Beginning	66,993,000	422,017,000	$ 73,000	$ (234,000)	354,863,000
Balance beginning			73,181,750	41,309
Balance Ending at Jun. 30, 2018	(101,376,000)	542,062,000	$ 82,000	$ (234,000)	(440,534,000)
Net loss	85,671,000
Balance Beginning	85,232,000	481,781,000	$ 77,000	$ (234,000)	(396,392,000)
Balance beginning			77,134,683	41,309
Balance beginning at Mar. 31, 2018			77,134,683	41,309
Balance Ending at Jun. 30, 2018			82,539,417	41,309
Issuance of restricted stock (in shares)			1,333,011
Forfeiture of restricted stock (in shares)			(6,750)
Issuance of common stock in At-the-Market offerings			3,744,605
Shares issued in connection with in-licensing agreements			333,868
Balance Beginning at Mar. 31, 2018	85,232,000	481,781,000	$ 77,000	$ (234,000)	(396,392,000)
Balance Beginning	85,232,000	481,781,000	77,000	$ (234,000)	(396,392,000)
Issuance of common stock in At-the-Market offerings	52,022,000	52,018,000	$ 4,000
Compensation in respect of restricted stock granted to employees, directors and consultants	4,264,000	4,264,000
Balance beginning			77,134,683	41,309
Balance Ending at Jun. 30, 2018	(101,376,000)	542,062,000	$ 82,000	$ (234,000)	(440,534,000)
Net loss	44,142,000				(44,142,000)
Issuance of restricted stock		(1,000)	1,000
Shares issued in connection with in-licensing agreements	4,000,000	4,000,000
Balance Beginning	(101,376,000)	542,062,000	$ 82,000	$ (234,000)	(440,534,000)
Balance beginning			82,539,417	41,309
Balance Beginning	24,036,000	552,531,000	$ (84,000)	$ (234,000)	(528,345,000)
Balance beginning			83,911,855	41,309,000
Balance beginning at Dec. 31, 2018			83,911,855	41,309,000
Balance Ending at Mar. 31, 2019			88,582,227	41,309,000
Issuance of restricted stock (in shares)			23,000
Forfeiture of restricted stock (in shares)			(67,628)
Issuance of common stock in At-the-Market offerings			4,715,000
Balance Beginning at Dec. 31, 2018	24,036,000	552,531,000	$ (84,000)	$ (234,000)	(528,345,000)
Balance Beginning	24,036,000	552,531,000	(84,000)	$ (234,000)	(528,345,000)
Issuance of common stock in At-the-Market offerings	27,499,000	27,494,000	$ 5,000
Compensation in respect of restricted stock granted to employees, directors and consultants	1,882,000	1,882,000
Balance beginning			83,911,855	41,309,000
Balance Ending at Mar. 31, 2019		582,900,000	$ 89,000	$ (234,000)	(563,501,000)
Net loss	(35,156,000)				(35,156,000)
Warrants issued with debt financing	$ 993,000
Balance beginning at Dec. 31, 2018			83,911,855	41,309,000
Balance Ending at Jun. 30, 2019			93,405,248	41,309,000
Shares issued in connection with in-licensing agreements	100,000
Balance Beginning at Dec. 31, 2018	$ 24,036,000	552,531,000	$ (84,000)	$ (234,000)	(528,345,000)
Balance Beginning	13,205,000	552,531,000	$ (84,000)	$ (234,000)	(528,345,000)
Balance beginning			83,911,855	41,309,000
Balance Ending at Jun. 30, 2019	13,205,000	613,059,000	$ 93,000	$ (234,000)	(599,713,000)
Net loss	71,368,000
Balance Beginning		582,900,000	$ 89,000	$ (234,000)	(563,501,000)
Balance beginning			88,582,227	41,309,000
Balance beginning at Mar. 31, 2019			88,582,227	41,309,000
Balance Ending at Jun. 30, 2019			93,405,248	41,309,000
Issuance of restricted stock (in shares)			1,245,080
Forfeiture of restricted stock (in shares)			(38,418)
Issuance of common stock in At-the-Market offerings			3,616,359
Balance Beginning at Mar. 31, 2019		582,900,000	$ 89,000	$ (234,000)	(563,501,000)
Balance Beginning	13,205,000	582,900,000	89,000	$ (234,000)	(563,501,000)
Issuance of common stock in At-the-Market offerings	28,395,000	28,392,000	$ 3,000
Compensation in respect of restricted stock granted to employees, directors and consultants	1,757,000	1,757,000
Balance beginning			88,582,227	41,309,000
Balance Ending at Jun. 30, 2019	13,205,000	613,059,000	$ 93,000	$ (234,000)	(599,713,000)
Net loss	36,213,000				(36,212,000)
Issuance of restricted stock		1,000
Issuance of common stock in public offering	11,000	11,000
Exercisable at June 30, 2019	5,684,217
Balance Beginning	$ 13,205,000	$ 613,059,000	$ 93,000	$ (234,000)	$ (599,713,000)
Balance beginning			93,405,248	41,309,000