Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data	Total	Series A Preferred Stock	Series B Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Beginning Balances at Dec. 31, 2011	$ 13,673			$ 33	$ 142,955	$ 13	$ (129,328)
Beginning Balances, Shares at Dec. 31, 2011				32,779
Stock option and warrant compensation expense to employees	3,499				3,499
Common stock issued upon exercise of common stock warrants	223				223
Common stock issued upon exercise of common stock warrants, shares				550
Exchange of Series B preferred stock for common stock, shares				2
Foreign currency translation adjustment	(8)					(8)
Net loss	(9,287)						(9,287)
Ending Balances at Dec. 31, 2012	8,100			33	146,677	5	(138,615)
Ending Balances, shares at Dec. 31, 2012				33,331
Stock option and warrant compensation expense to employees, directors and vendors	2,656				2,656
Proceeds from sale of common stock, net of offering costs	6,892			2	6,890
Proceeds from sale of common stock, net of offering costs, shares				1,169
Common stock issued upon exercise of common stock warrants	714			3	711
Common stock issued upon exercise of common stock warrants, shares				3,152
Exchange of Series A preferred stock for common stock,shares				40
Exchange of Series B preferred stock for common stock, shares				1
Common stock issued upon exercise of common stock options	1,060				1,060
Common stock issued upon exercise of common stock options, shares				241
Foreign currency translation adjustment	6					6
Net loss	(13,080)						(13,080)
Ending Balances at Dec. 31, 2013	6,348			38	157,994	11	(151,695)
Ending Balances, shares at Dec. 31, 2013				37,934
Stock based compensation expense to employees, directors and vendors	1,729				1,729
Proceeds from sale of common stock, net of offering costs	9,253			2	9,251
Proceeds from sale of common stock, net of offering costs, shares				2,500
Common stock issued upon exercise of common stock warrants	36				36
Common stock issued upon exercise of common stock warrants, shares				21
Foreign currency translation adjustment	138					138
Net loss	(14,234)						(14,234)
Ending Balances at Dec. 31, 2014	$ 3,270			$ 40	$ 169,010	$ 149	$ (165,929)
Ending Balances, shares at Dec. 31, 2014				40,455