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	Additional Paid-in Capital	Accumulated Deficit	LPC Program [Member]	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								$ 337			$ 337
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							$ (12)	(313)			(325)
Shares issued under the Lincoln Park commitment purchase agreement, net (in shares)							1,213,642
Net loss									$ (2,351)		(2,351)
Balance at Mar. 31, 2019	$ 968	$ 519,050	$ (513,475)	$ 6,543	$ (267)	$ (267)	$ 968	519,050	(513,742)		6,276
Balance (in shares) at Mar. 31, 2019	96,868,433						96,868,433
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								52			52
Shares issued under the at-the-market offering agreement, net							$ 8	215			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
Registered direct purchase agreement, net (in shares)										900,000
Net loss									(3,336)		(3,336)
Balance at Mar. 31, 2020							$ 1,084	$ 521,788	$ (520,116)		$ 2,756
Balance (in shares) at Mar. 31, 2020							108,457,731