CONSOLIDATED STATEMENT OF CHANGES IN CAPITAL DEFICIENCY (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Balance	$ (3,357)	$ (26,077)	$ (11,323)
Common stock issued for cash (net of issuance costs)		25,388	20,590
Share-based compensation	1,013	4,612	886
Share-based compensation related to restricted stock award, net of forfeitures	3,076	3,139
Exercise of options granted to employees and non-employees	112	1,199	299
Net Loss	(27,790)	(11,618)	(36,529)
Balance	(26,946)	(3,357)	(26,077)
Common Stock [Member]
Balance, shares	93,489,809	85,630,157	81,248,472
Balance	93	86	81
Common stock issued for cash (net of issuance costs) (in shares)		5,175,000	4,000,000
Common stock issued for cash (net of issuance costs)		5	4
Share-based compensation
Share-based compensation related to restricted stock award, net of forfeitures		1
Share-based compensation related to restricted stock award, net of forfeitures (shares)	(17,834)	1,496,792
Exercise of options granted to employees and non-employees		1	1
Exercise of options granted to employees and non-employees, shares	79,123	1,187,860	381,685
Net Loss
Balance	93	93	86
Balance, shares	93,551,098	93,489,809	85,630,157
Additional Paid-in Capital [Member]
Balance	180,145	145,814	124,044
Common stock issued for cash (net of issuance costs)		25,383	20,586
Share-based compensation	1,013	4,612	886
Share-based compensation related to restricted stock award, net of forfeitures	3,076	3,138
Exercise of options granted to employees and non-employees	112	1,198	298
Net Loss
Balance	184,346	180,145	145,814
Accumulated Deficit [Member]
Balance	(183,595)	(171,977)	(135,448)
Common stock issued for cash (net of issuance costs)
Share-based compensation
Share-based compensation related to restricted stock award, net of forfeitures
Exercise of options granted to employees and non-employees
Net Loss	(27,790)	(11,618)	(36,529)
Balance	$ (211,385)	$ (183,595)	$ (171,977)