Consolidated Statements of Stockholders' Equity (USD $) In Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit
Beginning Balance at Dec. 31, 2009	$ 86,266	$ 439	$ 348,572	$ (26)	$ (262,719)
Net loss	(33,853)				(33,853)
Other Comprehensive Income (Loss)	131			131
Comprehensive loss	(33,722)
Exercise of stock options, 240, 184, 348 shares, net for the year 2010, 2011 and 2012 respectively	552	2	550
Employee stock purchase plan sales, 51, 94, 110 shares for the year 2010, 2011 and 2012 respectively	283	1	282
Issuance of common stock, 761, 437, 4774 shares, net for the year 2010, 2011 and 2012 respectively	5,827	8	5,819
Purchases of treasury stock, 1 and 12, shares for the year 2010 and 2011 respectively	(5)		(5)
Stock-based compensation expense	6,302		6,302
Ending Balance at Dec. 31, 2010	65,503	450	361,520	105	(296,572)
Net loss	(56,948)				(56,948)
Other Comprehensive Income (Loss)	(65)			(65)
Comprehensive loss	(57,013)
Exercise of stock options, 240, 184, 348 shares, net for the year 2010, 2011 and 2012 respectively	278	2	276
Employee stock purchase plan sales, 51, 94, 110 shares for the year 2010, 2011 and 2012 respectively	300	1	299
Issuance of common stock, 761, 437, 4774 shares, net for the year 2010, 2011 and 2012 respectively	1,027	4	1,023
Purchases of treasury stock, 1 and 12, shares for the year 2010 and 2011 respectively	(61)		(61)
Stock-based compensation expense	4,772		4,772
Ending Balance at Dec. 31, 2011	14,806	457	367,829	40	(353,520)
Net loss	(39,081)				(39,081)
Other Comprehensive Income (Loss)	(13)			(13)
Comprehensive loss	(39,094)
Exercise of stock options, 240, 184, 348 shares, net for the year 2010, 2011 and 2012 respectively	539	3	536
Employee stock purchase plan sales, 51, 94, 110 shares for the year 2010, 2011 and 2012 respectively	321	1	320
Issuance of common stock, 761, 437, 4774 shares, net for the year 2010, 2011 and 2012 respectively	18,807	48	18,759
Stock-based compensation expense	4,167		4,167
Ending Balance at Dec. 31, 2012	$ (454)	$ 509	$ 391,611	$ 27	$ (392,601)