Condensed Consolidated Statement of Stockholders' Equity - 9 months ended Sep. 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)		1,521,211
Issuance of restricted stock		$ 2		(2)
Forfeiture of restricted stock (in shares)		(155,446)
Forfeiture of restricted stock	[1]
Issuance of common stock in At-the-Market offerings (net of offering costs of $2.0 million) (in shares)		8,091,949
Issuance of common stock in At-the-Market offerings (net of offering costs of $2.0 million)		$ 8		108,937			108,945
Compensation in respect of restricted stock granted to employees, directors and consultants				11,428			11,428
Shares issued in connection with in-licensing agreements (in shares)		333,868
Shares issued in connection with in-licensing agreements			[1]	4,000			4,000
Net loss						(119,622)	(119,622)
Balance (in shares) at Sep. 30, 2018		82,973,332			41,309
Balance at Sep. 30, 2018		$ 83		$ 546,380	$ (234)	$ (474,485)	$ 71,744

[1] Amount less than one thousand dollars.