Condensed Consolidated Statement of Stockholders' Equity - 6 months ended Jun. 30, 2018 - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Total
Balance (in shares) at Dec. 31, 2017	73,181,750		41,309
Balance at Dec. 31, 2017	$ 73	$ 422,017	$ (234)	$ (354,863)	$ 66,993
Issuance of restricted stock (in shares)	1,420,511
Issuance of restricted stock	$ 1	(1)
Forfeiture of restricted stock (in shares)	(130,661)
Issuance of common stock in At-the-Market offerings (net of offering costs of $1.9 million) (in shares)	7,733,949
Issuance of common stock in At-the-Market offerings (net of offering costs of $1.9 million)	$ 8	104,445			104,453
Compensation in respect of restricted stock granted to employees, directors and consultants		11,601			11,601
Shares issued in connection with in-licensing agreements (in shares)	333,868
Shares issued in connection with in-licensing agreements		4,000			4,000
Net loss				(85,671)	(85,671)
Balance (in shares) at Jun. 30, 2018	82,539,417		41,309
Balance at Jun. 30, 2018	$ 82	$ 542,062	$ (234)	$ (440,534)	$ 101,376