Consolidated Statements of Changes in Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock [Member]	Common Stock [Member] February 2010 Financing [Member]	Common Stock [Member] April 2010 Financing [Member]	Common Stock [Member] June 2010 Financing [Member]	Common Stock [Member] October 2010 Financing [Member]	Common Stock [Member] February 2011 Financing [Member]	Common Stock [Member] March 2012 Financing [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] February 2010 Financing [Member]	Additional Paid-in Capital [Member] April 2010 Financing [Member]	Additional Paid-in Capital [Member] June 2010 Financing [Member]	Additional Paid-in Capital [Member] October 2010 Financing [Member]	Additional Paid-in Capital [Member] February 2011 Financing [Member]	Additional Paid-in Capital [Member] March 2012 Financing [Member]	Accumulated Deficit [Member]	Accumulated Deficit [Member] February 2010 Financing [Member]	Accumulated Deficit [Member] April 2010 Financing [Member]	Accumulated Deficit [Member] June 2010 Financing [Member]	Accumulated Deficit [Member] October 2010 Financing [Member]	Accumulated Deficit [Member] February 2011 Financing [Member]	Accumulated Deficit [Member] March 2012 Financing [Member]	Treasury Stock [Member]	Treasury Stock [Member] February 2010 Financing [Member]	Treasury Stock [Member] April 2010 Financing [Member]	Treasury Stock [Member] June 2010 Financing [Member]	Treasury Stock [Member] October 2010 Financing [Member]	Treasury Stock [Member] February 2011 Financing [Member]	Treasury Stock [Member] March 2012 Financing [Member]	Total [Member]	Total [Member] February 2010 Financing [Member]	Total [Member] April 2010 Financing [Member]	Total [Member] June 2010 Financing [Member]	Total [Member] October 2010 Financing [Member]	Total [Member] February 2011 Financing [Member]	Total [Member] March 2012 Financing [Member]
Balance at Dec. 31, 2009		$ 8							$ 361,622							$ (357,280)							$ (3,054)							$ 1,296
Balance (in shares) at Dec. 31, 2009		8,446,000																					(21,000)
Changes in Stockholders' Equity [Roll Forward]
Net loss	(19,175)	0							0							(19,175)							0							(19,175)
Issuance of common stock, restricted stock awards (in shares)		155,000																					0
Issuance of common stock, restricted stock awards		0							0							0							0							0
Issuance of common stock, 401(k) employer match (in shares)	61,158	61,000																					0
Issuance of common stock, 401(k) employer match		1							223							0							0							224
Issuance of common stock, financing (in shares)			1,833,000	270,000	2,381,000	159,000																		0	0	0	0
Issuance of common stock, financing			2	0	2	0				9,379	2,105	9,092	452				0	0	0	0				0	0	0	0				9,381	2,105	9,094	452
Exercise of stock options for cash (in shares)	0
Issuance of common stock, CEFF financings (in shares)		517,000																					0
Issuance of common stock, CEFF financings		1							1,242							0							0							1,243
Stock-based compensation expense		0							1,406							0							0							1,406
Balance at Dec. 31, 2010		14							385,521							(376,455)							(3,054)							6,026
Balance (in shares) at Dec. 31, 2010		13,822,000																					(21,000)
Changes in Stockholders' Equity [Roll Forward]
Net loss	(20,965)	0							0							(20,965)							0							(20,965)
Issuance of common stock, restricted stock awards (in shares)		1,000																					0
Issuance of common stock, restricted stock awards		0							0							0							0							0
Issuance of common stock, 401(k) employer match (in shares)	265,185	265,000																					0
Issuance of common stock, 401(k) employer match		0							497							0							0							497
Issuance of common stock, financing (in shares)							10,000,000																					0
Issuance of common stock, financing							10							13,513							0							0							13,523
Exercise of stock options for cash (in shares)	0
Issuance of common stock, CEFF financings (in shares)		515,000																					0
Issuance of common stock, CEFF financings		1							1,315							0							0							1,316
Stock-based compensation expense		0							867							0							0							867
Balance at Dec. 31, 2011	1,264	25							401,713							(397,420)							(3,054)							1,264
Balance (in shares) at Dec. 31, 2011	24,581,814	24,603,000																					(21,000)
Changes in Stockholders' Equity [Roll Forward]
Net loss	(37,315)	0							0							(37,315)							0							(37,315)
Issuance of common stock, 401(k) employer match (in shares)	316,543	317,000																					0
Issuance of common stock, 401(k) employer match		0							763							0							0							763
Issuance of common stock, financing (in shares)								16,072,000																					0
Issuance of common stock, financing								16							42,074							0							0							42,090
Issuance of common stock, ATM financing (in shares)		350,000																					0
Issuance of common stock, ATM financing		1							1,460							0							0							1,461
Exercise of common stock warrants (in shares)		2,289,000																					0
Exercise of common stock warrants		2							6,875							0							0							6,877
Exercise of stock options for cash (in shares)	3,000	3,000																					0
Exercise of stock options for cash		0							6							0							0							6
Issuance of common stock, consultants (in shares)		40,000																					0
Issuance of common stock, consultants		0							96							0							0							96
Stock-based compensation expense		0							2,411							0							0							2,411
Balance at Dec. 31, 2012	$ 17,653	$ 44							$ 455,398							$ (434,735)							$ (3,054)							$ 17,653
Balance (in shares) at Dec. 31, 2012	43,652,744	43,674,000																					(21,000)