Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Total
Balance at Dec. 31, 2015	$ 19	$ (8,432)	$ 132,690	$ (111,252)	$ 13
Balance, shares at Dec. 31, 2015	1,870,000	104,000
Common stock issued
Common stock issued, shares
Common stock issued through offerings, net of expenses	$ 2		857
Common stock issued through offerings, net of expenses, shares	200,000
Shares issued in debt exchange
Shares issued in debt exchange, shares
Exercise of warrants for cash, net of expenses	$ 1		15
Exercise of warrants for cash, net of expenses, shares	160,000
Issuance of debt exchange warrants, vendor warrants, and other
Treasury stock purchased
Treasury stock purchased, shares
Issuance of warrants, net of expenses			832
Stock-based compensation expense			131
Treasury stock reissued		$ 6,789	(6,789)
Treasury stock reissued, shares		(50,000)
Unrealized holding loss on available-for-sale securities, net of tax
Realized loss, net of tax					(13)
Net loss				(8,332)		(8,332)
Balance at Dec. 31, 2016	$ 22	$ (1,643)	127,736	(119,584)		6,531
Balance, shares at Dec. 31, 2016	2,230,000	54,000
Common stock issued
Common stock issued, shares	34,000
Common stock issued through offerings, net of expenses	$ 135		15,734
Common stock issued through offerings, net of expenses, shares	13,568,000
Shares issued in debt exchange	$ 38		11,605
Shares issued in debt exchange, shares	3,795,000
Exercise of warrants for cash, net of expenses	$ 83		6,778
Exercise of warrants for cash, net of expenses, shares	8,273,000
Reclass of warrant liability upon exercise of pre-funded warrants			2,337
Issuance of debt exchange warrants, vendor warrants, and other			600
Treasury stock purchased		$ (28)
Treasury stock purchased, shares		10,000
Issuance of warrants, net of expenses			7,212			7,212
Stock-based compensation expense			1,060
Treasury stock reissued
Treasury stock reissued, shares
Unrealized holding loss on available-for-sale securities, net of tax
Realized loss, net of tax
Net loss				(12,216)		(12,216)
Balance at Dec. 31, 2017	$ 278	$ (1,671)	$ 173,062	$ (131,800)		$ 39,869
Balance, shares at Dec. 31, 2017	27,900,000	64,000