Consolidated Statements of Changes in Equity (Unaudited) - USD ($) $ in Thousands		Series B Preferred Stock [Member]		Series C Preferred Stock [Member]		Series D Preferred Stock [Member]		Series B Convertible Preferred Stock [Member]		Series C Convertible Preferred Stock [Member]		Common Stock [Member]		Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2017			[1]		[1]		[1]						[1]	$ 143,079	$ (140,352)	$ 2,727
Balance, shares at Dec. 31, 2017		27,075		741,651		750						30,106
Net loss															(5,027)	(5,027)
Issuance of common shares, warrants, pre-funded warrants and exercise of pre-funded warrants													[1]	15,809		15,809
Issuance of common shares, warrants, pre-funded warrants and exercise of pre-funded warrants, shares												677,477
Redemption of Series D Preferred Stock							[1]							(750)		(750)
Redemption of Series D Preferred Stock, shares						(750)
Conversion of Series B Preferred Stock to common shares			[1]										[1]	274		274
Conversion of Series B Preferred Stock to common shares, shares		(9,772)										1,613
Conversion of Series C Preferred Stock to common shares					[1]								[1]	936		936
Conversion of Series C Preferred Stock to common shares, shares				(326,436)								22,896
Exercise of Unit Purchase Option													[1]	557		557
Exercise of Unit Purchase Option, shares												2,229
Accretion of redeemable preferred shares														(438)		(438)
Redemption of Series C Preferred Stock					[1]									(3,200)		(3,200)
Redemption of Series C Preferred Stock, shares				(353,792)
Share-based compensation related to restricted stock and stock options award, net of forfeitures of shares														64		64
Share-based compensation related to restricted stock and stock options award, net of forfeitures of shares, shares												(4)
Balance at Sep. 30, 2018			[1]		[1]		[1]						[1]	156,331	(145,379)	10,952
Balance, shares at Sep. 30, 2018		17,303		61,423								734,317
Balance at Jun. 30, 2018			[1]		[1]		[1]						[1]	147,466	(143,368)	4,098
Balance, shares at Jun. 30, 2018		17,303		378,840		300						129,505
Net loss															(2,011)	(2,011)
Issuance of common shares, warrants, pre-funded warrants and exercise of pre-funded warrants													[1]	8,867		8,867
Issuance of common shares, warrants, pre-funded warrants and exercise of pre-funded warrants, shares												600,334
Redemption of Series D Preferred Stock							[1]
Redemption of Series D Preferred Stock, shares						(300)
Conversion of Series C Preferred Stock to common shares					[1]								[1]
Conversion of Series C Preferred Stock to common shares, shares				(10,500)								4,480
Redemption of Series C Preferred Stock					[1]
Redemption of Series C Preferred Stock, shares				(306,917)
Share-based compensation related to restricted stock and stock options award, net of forfeitures of shares													[1]	(2)		(2)
Share-based compensation related to restricted stock and stock options award, net of forfeitures of shares, shares												(2)
Balance at Sep. 30, 2018			[1]		[1]		[1]						[1]	156,331	(145,379)	10,952
Balance, shares at Sep. 30, 2018		17,303		61,423								734,317
Balance at Dec. 31, 2018									[1]		[1]		[1]	156,355	(147,592)	8,763
Balance, shares at Dec. 31, 2018								17,303		61,423		768,615
Net loss															(7,483)	(7,483)
Issuance of common shares, warrants, pre-funded warrants and exercise of pre-funded warrants													[1]	6,331		6,331
Issuance of common shares, warrants, pre-funded warrants and exercise of pre-funded warrants, shares												2,588,828
Share-based compensation related to restricted stock and stock options award, net of forfeitures of shares													[1]	285		285
Share-based compensation related to restricted stock and stock options award, net of forfeitures of shares, shares												69,744
Conversion of Series C Convertible Preferred Stock to common shares	[1]
Conversion of Series C Convertible Preferred Stock to common shares, shares										(24,554)		29,728
Balance at Sep. 30, 2019									[1]		[1]		[1]	162,971	(155,075)	7,896
Balance, shares at Sep. 30, 2019								17,303		36,869		3,456,915
Balance at Jun. 30, 2019									[1]		[1]		[1]	158,579	(153,005)	5,574
Balance, shares at Jun. 30, 2019								17,303		38,806		1,397,133
Net loss															(2,070)	(2,070)
Issuance of common shares, warrants, pre-funded warrants and exercise of pre-funded warrants													[1]	4,285		4,285
Issuance of common shares, warrants, pre-funded warrants and exercise of pre-funded warrants, shares												2,057,444
Share-based compensation related to restricted stock and stock options award, net of forfeitures of shares													[1]	107		107
Share-based compensation related to restricted stock and stock options award, net of forfeitures of shares, shares												(142)
Conversion of Series C Convertible Preferred Stock to common shares	[1]
Conversion of Series C Convertible Preferred Stock to common shares, shares										(1,937)		2,480
Balance at Sep. 30, 2019									[1]		[1]		[1]	$ 162,971	$ (155,075)	$ 7,896
Balance, shares at Sep. 30, 2019								17,303		36,869		3,456,915

[1] Represents an amount less than $1 thousand