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	21			21
Restricted stock grants, net of cancellations	389		$ 1	388
Restricted stock grants, net of cancellations, shares			1,124,000
Cancellation of shares for payment of withholding tax	(88)			(88)
Cancellation of shares for payment of withholding tax, shares			(42,000)
Employee stock purchase plan	3			3
Employee stock purchase plan, shares			3,000
Common shares issued in stock offering, net of offering costs	10,759		$ 6	10,753
Common shares issued in stock offering, net offering costs, shares			6,027,000
Issuance of warrants in stock offering	(6,780)			(6,780)
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	(326)				(326)
Other	(3)			11	(14)
Comprehensive loss	(4,558)				(4,558)
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
BALANCE at Mar. 31, 2018	3,730		$ 18	239,179	(235,467)
BALANCE, Shares at Mar. 31, 2018		5,000
BALANCE, Shares at Mar. 31, 2018			18,237,000
Non-cash compensation recognized on stock options and ESPP	10			10
Restricted stock grants, net of cancellations	236			236
Cancellation of shares for payment of withholding tax	(53)			(53)
Cancellation of shares for payment of withholding tax, shares			(26,000)
Common shares issued in stock offering, net of offering costs	6,297		$ 3	6,294
Common shares issued in stock offering, net offering costs, shares			3,170,000
Issuance of warrants in stock offering	(3,872)			(3,872)
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	(185)				(185)
Other	(2)				(2)
Comprehensive loss	(2,177)				(2,177)
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
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	$ 18			18
Restricted stock grants, net of cancellations	770		$ 1	769
Restricted stock grants, net of cancellations, shares			1,225,000
Cancellation of shares for payment of withholding tax	(315)			(315)
Cancellation of shares for payment of withholding tax, shares			(138,000)
Employee stock purchase plan	5			5
Employee stock purchase plan, shares			2,000
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, shares			3,000
Conversion of preferred stock to common stock, shares			9,000
Preferred stock dividends	(67)				(67)
Cumulative effect of adoption of ASC 842	93				93
Comprehensive loss	3,484				3,484
BALANCE at Jun. 30, 2019	$ 29,666		$ 32	262,215	(232,581)
BALANCE, Shares at Jun. 30, 2019	5,500	1,000
BALANCE, Shares at Jun. 30, 2019	32,041,685		32,042,000
BALANCE at Mar. 31, 2019	$ 26,038		$ 32	261,990	(235,984)
BALANCE, Shares at Mar. 31, 2019		1,000
BALANCE, Shares at Mar. 31, 2019			32,065,000
Non-cash compensation recognized on stock options and ESPP	10			10
Restricted stock grants, net of cancellations	323			323
Cancellation of shares for payment of withholding tax	(108)			(108)
Cancellation of shares for payment of withholding tax, shares			(35,000)
Exercise of warrants, shares			3,000
Conversion of preferred stock to common stock, shares			9,000
Preferred stock dividends	(34)				(34)
Other	1				1
Comprehensive loss	3,436				3,436
BALANCE at Jun. 30, 2019	$ 29,666		$ 32	$ 262,215	$ (232,581)
BALANCE, Shares at Jun. 30, 2019	5,500	1,000
BALANCE, Shares at Jun. 30, 2019	32,041,685		32,042,000