Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock [Member] Series B Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Comprehensive Deficit [Member]
BALANCE at Dec. 31, 2017	$ 4,567		$ 14	$ 237,486	$ (232,933)
BALANCE, Shares at Dec. 31, 2017		5,000
BALANCE, Shares at Dec. 31, 2017			14,269,000
Non-cash compensation recognized on stock options and ESPP	31			31
Restricted stock grants, net of cancellations	643		$ 1	642
Restricted stock grants, net of cancellations, shares			1,124,000
Cancellation of shares for payment of withholding tax	(151)			(151)
Cancellation of shares for payment of withholding tax, shares			(68,000)
Employee stock purchase plan	5			5
Employee stock purchase plan, shares			5,000
Common shares issued in stock offering, net of offering costs	10,748		$ 6	10,742
Common shares issued in stock offering, net offering costs, shares			6,027,000
Issuance of warrants in stock offering	(6,792)			(6,792)
Exercise of warrants, shares			25,000
Conversion of preferred stock to common stock			$ 4	(4)
Conversion of preferred stock to common stock, shares		(4,000)	3,623,000
Preferred stock dividends	(370)				(370)
Other	(1)			11	(12)
Comprehensive loss	(5,542)				(5,542)
BALANCE at Sep. 30, 2018	3,138		$ 25	241,970	(238,857)
BALANCE, Shares at Sep. 30, 2018		1,000
BALANCE, Shares at Sep. 30, 2018			25,005,000
BALANCE at Jun. 30, 2018	3,984		$ 25	241,790	(237,831)
BALANCE, Shares at Jun. 30, 2018		1,000
BALANCE, Shares at Jun. 30, 2018			25,004,000
Non-cash compensation recognized on stock options and ESPP	10			10
Restricted stock grants, net of cancellations	254			254
Cancellation of shares for payment of withholding tax	(64)			(64)
Cancellation of shares for payment of withholding tax, shares			(26,000)
Employee stock purchase plan	2			2
Employee stock purchase plan, shares			2,000
Common shares issued in stock offering, net of offering costs	(10)			(10)
Issuance of warrants in stock offering	(12)			(12)
Exercise of warrants, shares			25,000
Preferred stock dividends	(43)				(43)
Comprehensive loss	(983)				(983)
BALANCE at Sep. 30, 2018	3,138		$ 25	241,970	(238,857)
BALANCE, Shares at Sep. 30, 2018		1,000
BALANCE, Shares at Sep. 30, 2018			25,005,000
BALANCE at Dec. 31, 2018	$ 20,563		$ 28	256,626	(236,091)
BALANCE, Shares at Dec. 31, 2018	5,500	1,000
BALANCE, Shares at Dec. 31, 2018	28,241,129		28,242,000
Non-cash compensation recognized on stock options and ESPP	$ 30			30
Restricted stock grants, net of cancellations	1,109		$ 1	1,108
Restricted stock grants, net of cancellations, shares			1,225,000
Cancellation of shares for payment of withholding tax	(506)			(506)
Cancellation of shares for payment of withholding tax, shares			(176,000)
Employee stock purchase plan	10			10
Employee stock purchase plan, shares			4,000
Common shares issued in stock offering, net of offering costs	(14)			(14)
Common shares issued in connection with Smart Retail acquisition, net	5,129		$ 3	5,126
Common shares issued in connection, with Smart Retail acquisition, net, shares			2,699,000
Exercise of warrants	11,403		$ 5	11,398
Exercise of warrants, shares			5,304,000
Exercise of stock options	38			38
Exercise of stock options, shares			10,000
Conversion of preferred stock to common stock			$ 1	(1)
Conversion of preferred stock to common stock, shares		(1,000)	1,180,000
Preferred stock dividends	(119)				(119)
Cumulative effect of adoption of ASC 842	93				93
Comprehensive loss	7,051				7,051
BALANCE at Sep. 30, 2019	$ 44,787		$ 38	273,815	(229,066)
BALANCE, Shares at Sep. 30, 2019	5,500
BALANCE, Shares at Sep. 30, 2019	38,487,090		38,488,000
BALANCE at Jun. 30, 2019	$ 29,666		$ 32	262,215	(232,581)
BALANCE, Shares at Jun. 30, 2019		1,000
BALANCE, Shares at Jun. 30, 2019			32,042,000
Non-cash compensation recognized on stock options and ESPP	10			10
Restricted stock grants, net of cancellations	340			340
Cancellation of shares for payment of withholding tax	(191)			(191)
Cancellation of shares for payment of withholding tax, shares			(38,000)
Employee stock purchase plan	6			6
Employee stock purchase plan, shares			2,000
Exercise of warrants	11,403		$ 5	11,398
Exercise of warrants, shares			5,301,000
Exercise of stock options	38			38
Exercise of stock options, shares			10,000
Conversion of preferred stock to common stock			$ 1	(1)
Conversion of preferred stock to common stock, shares		(1,000)	1,171,000
Preferred stock dividends	(52)				(52)
Comprehensive loss	3,567				3,567
BALANCE at Sep. 30, 2019	$ 44,787		$ 38	$ 273,815	$ (229,066)
BALANCE, Shares at Sep. 30, 2019	5,500
BALANCE, Shares at Sep. 30, 2019	38,487,090		38,488,000