Statements of Changes in Preferred Stock and Stockholders' Equity (Deficit) (USD $)	Total USD ($)	All Other USD ($)	Services USD ($)	Non-employee services USD ($)	Private Placement USD ($)	Employees USD ($)	Registered direct offering USD ($)	Employee Stock Option USD ($)	Securities Offering USD ($)	Collaboration Agreement USD ($)	Series A Preferred Stock USD ($)	Warrant Exercise USD ($)	Common Stock USD ($)	Common Stock All Other USD ($)	Common Stock Services USD ($)	Common Stock Private Placement USD ($)	Common Stock Registered direct offering USD ($)	Common Stock Employee Stock Option USD ($)	Common Stock Securities Offering USD ($)	Common Stock Collaboration Agreement USD ($)	Common Stock Non Employee Stock Options	Additional Paid in Capital, Common Stock USD ($)	Additional Paid in Capital, Common Stock All Other USD ($)	Additional Paid in Capital, Common Stock Services USD ($)	Additional Paid in Capital, Common Stock Non-employee services USD ($)	Additional Paid in Capital, Common Stock Private Placement USD ($)	Additional Paid in Capital, Common Stock Employees USD ($)	Additional Paid in Capital, Common Stock Registered direct offering USD ($)	Additional Paid in Capital, Common Stock Employee Stock Option USD ($)	Additional Paid in Capital, Common Stock Securities Offering USD ($)	Additional Paid in Capital, Common Stock Collaboration Agreement USD ($)	Other Additional Capital USD ($)	Other Additional Capital Non-employee services USD ($)	Other Additional Capital Private Placement USD ($)	Accumulated Deficit during Development Stage USD ($)
Beginning Balance at Sep. 09, 2003	$ 500,000																					$ 500,000
Beginning Balance (in shares) at Sep. 09, 2003													250,487
Net loss	(160,000)																																		(160,000)
Ending Balance at Dec. 31, 2003	340,000																					500,000													(160,000)
Ending Balance (in shares) at Dec. 31, 2003													250,487
Fair value of options/warrants issued				264,000																					13,000								251,000
Issuance of common stock (in shares)														2,254,389	256,749
Issuance of common stock		4,500,000	439,000											2,000	1,000								4,498,000	438,000
Net loss	(5,687,000)																																		(5,687,000)
Ending Balance at Dec. 31, 2004	(144,000)												3,000									5,449,000										251,000			(5,847,000)
Beginning Balance (in shares) at Dec. 31, 2004													2,761,625
Issuance of Series A convertible preferred stock (net of expenses of $1,340 and warrant cost of $1,683) (in shares)											4,197,946
Issuance of Series A convertible preferred stock (net of expenses of $1,340 and warrant cost of $1,683)	15,077,000										15,077,000
Fair value of options/warrants issued	1,683,000			99,000								1,683,000													54,000								45,000
Issuance of common stock to EasyWeb Stockholders													189,922
Conversion of Series A convertible preferred stock @ $0.001 into $0.001 common stock on September 13, 2005 at an exchange ratio of .500974 (in shares)											(4,197,946)		4,197,823
Conversion of Series A convertible preferred stock @ $0.001 into $0.001 common stock on September 13, 2005 at an exchange ratio of .500974											(15,077,000)	(1,683,000)	4,000									15,073,000										1,683,000
Exercise of stock options (in shares)													98,622
Exercise of stock options	4,000																					4,000
Net loss	(9,517,000)																																		(9,517,000)
Ending Balance at Dec. 31, 2005	7,202,000												7,000									20,580,000										1,979,000			(15,364,000)
Ending Balance (in shares) at Dec. 31, 2005													7,247,992
Fair value of options/warrants issued	13,092,000																															13,092,000
Stock-based compensation	2,777,000																					2,777,000
Issuance of common stock (in shares)															25,000	7,991,256
Issuance of common stock			106,000		21,188,000											8,000								106,000		21,180,000
Exercise of stock options (in shares)													5,845
Exercise of stock options	25,000																					25,000
Exercise of warrants to purchase common stock (in shares)													2,806
Net loss	(17,857,000)																																		(17,857,000)
Ending Balance at Dec. 31, 2006	26,533,000												15,000									44,668,000										15,071,000			(33,221,000)
Ending Balance (in shares) at Dec. 31, 2006													15,272,899
Fair value of options/warrants issued	5,433,000																															5,433,000
Stock-based compensation				120,000		1,318,000																			120,000		1,318,000
Issuance of common stock (in shares)																5,910,049
Issuance of common stock					23,538,000											6,000										23,532,000
Exercise of stock options (in shares)													46,016
Exercise of stock options	36,000																					36,000
Issuance of restricted common stock (in shares)													70,000
Net loss	(26,608,000)																																		(26,608,000)
Ending Balance at Dec. 31, 2007	30,370,000												21,000									69,674,000										20,504,000			(59,829,000)
Ending Balance (in shares) at Dec. 31, 2007													21,298,964
Stock-based compensation	1,600,000																					1,600,000
Issuance of restricted common stock (in shares)													586,500
Issuance of restricted common stock													1,000									(1,000)
Cancelled/ Forfeiture of unvested restricted common stock													(25,000)
Other																						1,000													(1,000)
Net loss	(25,231,000)																																		(25,231,000)
Ending Balance at Dec. 31, 2008	6,739,000												22,000									71,274,000										20,504,000			(85,061,000)
Ending Balance (in shares) at Dec. 31, 2008													21,860,464
Cummulative effect of a change in accounting principle - January 1, 2009 reclassification of warrants to warrant liabilities	(72,000)																															(1,638,000)			1,566,000
Stock-based compensation	2,181,000																					2,181,000
Exercise of stock options (in shares)																		102,564
Exercise of stock options								73,000																					73,000
Exercise of warrants to purchase common stock (in shares)													136,986
Exercise of warrants to purchase common stock	279,000																					279,000
Issuance of restricted common stock (in shares)													1,400,500
Issuance of restricted common stock													2,000									(2,000)
Repurchase of shares of restricted common stock (in shares)													(103,823)
Repurchase of shares of restricted common stock	(380,000)																					(380,000)
Cancelled/ Forfeiture of unvested restricted common stock													(69,500)
Issuance of common stock and warrants (in shares)																2,772,337	15,484,000
Issuance of common stock and warrants					4,595,000		22,338,000									3,000	15,000									385,000		22,323,000						4,207,000
Net loss	(7,649,000)																																		(7,649,000)
Ending Balance at Dec. 31, 2009	28,104,000												42,000									96,133,000										23,073,000			(91,144,000)
Ending Balance (in shares) at Dec. 31, 2009													41,583,528
Stock-based compensation	3,637,000																					3,637,000
Issuance of common stock (in shares)																	7,000,000
Issuance of common stock							32,804,000										7,000											32,797,000
Exercise of stock options (in shares)	196,167																	196,167
Exercise of stock options								225,000																					225,000
Exercise of warrants to purchase common stock (in shares)													39,225
Exercise of warrants to purchase common stock	121,000																					360,000										(239,000)
Issuance of restricted common stock (in shares)													115,000
Repurchase of shares of restricted common stock (in shares)													(416,108)
Repurchase of shares of restricted common stock	(1,668,000)												(1,000)									(1,667,000)
Cancelled/ Forfeiture of unvested restricted common stock													(51,250)
Expired warrants																						45,000										(45,000)
Net loss	(32,670,000)																																		(32,670,000)
Ending Balance at Dec. 31, 2010	30,553,000												48,000									131,530,000										22,789,000			(123,814,000)
Ending Balance (in shares) at Dec. 31, 2010													48,466,562
Stock-based compensation	2,759,000																					2,759,000
Issuance of common stock (in shares)																			11,040,000	6,063,161
Issuance of common stock									59,806,000	28,858,000									11,000	6,000										59,795,000	28,852,000
Exercise of stock options (in shares)	479,666																	479,666			6,904
Exercise of stock options								981,000										1,000											980,000
Exercise of warrants to purchase common stock (in shares)													2,377,571
Exercise of warrants to purchase common stock	12,701,000												2,000									21,766,000										(9,067,000)
Issuance of restricted common stock (in shares)													848,406
Issuance of restricted common stock													1,000									(1,000)
Repurchase of shares of restricted common stock (in shares)													(59,559)
Repurchase of shares of restricted common stock	(273,000)																					(273,000)
Cancelled/ Forfeiture of unvested restricted common stock													(16,667)
Expired warrants																						1,111,000										(1,111,000)
Net loss	(63,778,000)																																		(63,778,000)
Ending Balance at Dec. 31, 2011	71,607,000												69,000									246,519,000										12,611,000			(187,592,000)
Ending Balance (in shares) at Dec. 31, 2011													69,206,044
Stock-based compensation	4,880,000																					4,880,000
Issuance of common stock (in shares)																	10,114,401			3,636,926
Issuance of common stock							49,170,000			18,694,000							11,000			3,000								49,159,000			18,691,000
Exercise of stock options (in shares)	8,300																	8,300
Exercise of stock options								30,000																					30,000
Exercise of warrants to purchase common stock (in shares)													259,660
Exercise of warrants to purchase common stock	742,000																					1,011,000										(269,000)
Issuance of restricted common stock (in shares)													258,032
Repurchase of shares of restricted common stock (in shares)													(123,153)
Repurchase of shares of restricted common stock	(546,000)																					(546,000)
Cancelled/ Forfeiture of unvested restricted common stock													(123,370)
Expired warrants																						5,433,000										(5,433,000)
Net loss	(96,132,000)																																		(96,132,000)
Ending Balance at Dec. 31, 2012	$ 48,445,000												$ 83,000									$ 325,177,000										$ 6,909,000			$ (283,724,000)
Ending Balance (in shares) at Dec. 31, 2012													83,236,840