CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Previously Reported Common Stock	Previously Reported Additional Paid-in Capital	Previously Reported Accumulated Deficit	Previously Reported	Cumulative Effect Adjustment Accumulated Deficit	Cumulative Effect Adjustment	Common Stock Subscription Agreement	Common Stock Private Placement	Common Stock	Additional Paid-in Capital Subscription Agreement	Additional Paid-in Capital Private Placement	Additional Paid-in Capital	Accumulated Deficit	LPC Program [Member]	Subscription Agreement	Private Placement	Total
Balance at Dec. 31, 2018	$ 955	$ 517,806	$ (511,124)	$ 7,637
Balance (in shares) at Dec. 31, 2018	95,620,796
Increase (Decrease) in Stockholders' Equity
Stock compensation accrued and shares issued for vested stock awards									$ 3			$ 426					$ 429
Stock compensation accrued and shares issued for vested stock awards (in shares)									312,000
Modification of previously awarded KELTIP Units												583					583
Shares issued under the at-the-market offering agreement, net									$ 1			11					12
Shares issued under the at-the-market offering agreement, net (in shares)									33,995
Shares issued under the Lincoln Park commitment purchase agreement, net									$ (21)			(507)					(528)
Shares issued under the Lincoln Park commitment purchase agreement, net (in shares)									2,113,642
Net loss													$ (4,809)				(4,809)
Balance at Jun. 30, 2019	$ 980	$ 519,333	$ (515,933)	$ 4,380	$ (267)	$ (267)			$ 980			519,333	(516,200)				4,113
Balance (in shares) at Jun. 30, 2019	98,080,433								98,080,433
Balance at Dec. 31, 2019									$ 1,067			521,314	(516,780)				5,601
Balance (in shares) at Dec. 31, 2019									106,734,279
Increase (Decrease) in Stockholders' Equity
Stock compensation accrued and shares issued for vested stock awards												666					666
Shares issued under the at-the-market offering agreement, net									$ 9			214					223
Shares issued under the at-the-market offering agreement, net (in shares)									823,452
Shares issued under the Lincoln Park commitment purchase agreement, net									$ 9			207					216
Shares issued under the Lincoln Park commitment purchase agreement, net (in shares)									900,000
Stock Issued During Period, Value, New Issues							$ 47	$ 150		$ 882	$ 2,561				$ 929	$ 2,711
Stock Issued During Period, Shares, New Issues							4,719,207	15,000,000						900,000
Net loss													(5,659)				(5,659)
Balance at Jun. 30, 2020									$ 1,282			$ 525,844	$ (522,439)				$ 4,687
Balance (in shares) at Jun. 30, 2020									128,176,938