Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock Issued [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning balance at Dec. 31, 2013	$ 3,956	$ 205	$ 228,038	$ (212,172)	$ (8,082)	$ (4,033)
Beginning balance, shares at Dec. 31, 2013		20,465,984
Proceeds from issuance of common stock, net	11,138	$ 29	11,109
Proceeds from issuance of Common Stock, shares		2,891,566
Issuance of common stock for option awards exercised	$ 14		14
Issuance of common stock for option awards exercised, shares	2,914	2,914
Issuance of Common Stock for warrants exercised	$ 529	$ 1	528
Issuance of Common Stock for warrants exercised, shares		86,366
Issuance of Common Stock related to employee stock programs	194	$ 5	189
Issuance of Common Stock related to employee stock programs, shares		643,706
Amortization/forfeitures of unearned compensation	3,988		3,988
Amortization/forfeitures of unearned compensation, shares		(44,496)
Restricted stock vestings tax withholding	(797)				(797)
Series B convertible preferred stock conversions	5		5
Series B convertible preferred stock conversions, shares		937
Series B convertible preferred stock dividend	(589)		(589)
Other comprehensive gain (loss)	7					7
Net loss	(14,232)			(14,232)
Ending balance at Dec. 31, 2014	4,213	$ 240	243,282	(226,404)	(8,879)	(4,026)
Ending balance, shares at Dec. 31, 2014		24,046,977
Proceeds from issuance of common stock, net	15,942	$ 27	15,915
Proceeds from issuance of Common Stock, shares		2,728,712
Issuance of common stock for option awards exercised	$ 282		282
Issuance of common stock for option awards exercised, shares	59,638	41,750
Issuance of Common Stock for warrants exercised	$ 378	$ 1	377
Issuance of Common Stock for warrants exercised, shares		50,184
Issuance of Common Stock related to employee stock programs	271	$ 8	263
Issuance of Common Stock related to employee stock programs, shares		819,632
Amortization/forfeitures of unearned compensation	5,178		5,178
Amortization/forfeitures of unearned compensation, shares		(53,819)
Restricted stock vestings tax withholding	(874)				(874)
Reissuance of treasury shares			(514)		514
Series B convertible preferred stock conversions	17		17
Series B convertible preferred stock conversions, shares		3,417
Series B convertible preferred stock dividend	(588)		(588)
Other comprehensive gain (loss)	(1)					(1)
Net loss	(15,681)			(15,681)
Ending balance at Dec. 31, 2015	9,137	$ 276	264,212	(242,085)	(9,239)	(4,027)
Ending balance, shares at Dec. 31, 2015		27,636,853
Issuance of common stock for option awards exercised	$ 236		236
Issuance of common stock for option awards exercised, shares	56,250
Issuance of Common Stock related to employee stock programs	$ 383		383
Issuance of Common Stock related to employee stock programs, shares		88,282
Amortization/forfeitures of unearned compensation	5,158	$ (1)	5,159
Amortization/forfeitures of unearned compensation, shares		(220,594)
Restricted stock vestings tax withholding	(440)				(440)
Reissuance of treasury shares			(5,224)		5,224
Series B convertible preferred stock conversions	34		34
Series B convertible preferred stock conversions, shares		6,820
Series B convertible preferred stock dividend	(586)		(586)
Other comprehensive gain (loss)	(20)					(20)
Net loss	(20,977)			(20,977)
Ending balance at Dec. 31, 2016	$ (7,075)	$ 275	$ 264,214	$ (263,062)	$ (4,455)	$ (4,047)
Ending balance, shares at Dec. 31, 2016		27,511,361