Stock Based Compensation (Details) (USD $)	9 Months Ended		9 Months Ended			9 Months Ended														3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended						3 Months Ended		9 Months Ended			9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Employees [Member]	Sep. 30, 2012 Employees [Member]	Sep. 30, 2013 Employees and Directors [Member]	Sep. 30, 2013 Senior management [Member]	Sep. 30, 2012 Senior management [Member]	Sep. 30, 2013 Directors and nonemployees [Member]	Sep. 30, 2012 Directors and nonemployees [Member]	Sep. 30, 2013 Stock Options [Member]	Sep. 30, 2013 Stock Options [Member] Range $ 1.83 - 3.00 [Member]	Sep. 30, 2013 Stock Options [Member] Range $ 3.01 - 7.00 [Member]	Sep. 30, 2013 Stock Options [Member] Range $ 7.01 - 8.50 [Member]	Sep. 30, 2013 Stock Options [Member] Range $ 8.51 - 32.55 [Member]	Sep. 30, 2013 Stock Options [Member] Maximum [Member]	Sep. 30, 2013 Stock Options [Member] Employees [Member]	Sep. 30, 2013 Stock Options [Member] Non employees [Member]	Sep. 30, 2013 Stock Options And Warrants [Member]	Sep. 30, 2012 Stock Options And Warrants [Member]	Sep. 30, 2013 Stock Options And Warrants [Member] Employees [Member]	Sep. 30, 2012 Stock Options And Warrants [Member] Employees [Member]	Sep. 30, 2013 Stock Options And Warrants [Member] Employees [Member]	Sep. 30, 2012 Stock Options And Warrants [Member] Employees [Member]	Sep. 30, 2013 Stock Options And Warrants [Member] Non-Employees [Member]	Sep. 30, 2012 Stock Options And Warrants [Member] Non-Employees [Member]	Sep. 30, 2013 Stock Options And Warrants [Member] Non-Employees [Member]	Sep. 30, 2012 Stock Options And Warrants [Member] Non-Employees [Member]	Sep. 30, 2013 Stock Options And Warrants [Member] Research and Development Expense [Member] Employees [Member]	Sep. 30, 2012 Stock Options And Warrants [Member] Research and Development Expense [Member] Employees [Member]	Sep. 30, 2013 Stock Options And Warrants [Member] Research and Development Expense [Member] Employees [Member]	Sep. 30, 2012 Stock Options And Warrants [Member] Research and Development Expense [Member] Employees [Member]	Sep. 30, 2013 Stock Options And Warrants [Member] Research and Development Expense [Member] Non-Employees [Member]	Sep. 30, 2012 Stock Options And Warrants [Member] Research and Development Expense [Member] Non-Employees [Member]	Sep. 30, 2013 Stock Options And Warrants [Member] Research and Development Expense [Member] Non-Employees [Member]	Sep. 30, 2012 Stock Options And Warrants [Member] Research and Development Expense [Member] Non-Employees [Member]	Sep. 30, 2013 Stock Options And Warrants [Member] General and Administrative Expense [Member] Employees [Member]	Sep. 30, 2012 Stock Options And Warrants [Member] General and Administrative Expense [Member] Employees [Member]	Sep. 30, 2013 Stock Options And Warrants [Member] General and Administrative Expense [Member] Employees [Member]	Sep. 30, 2012 Stock Options And Warrants [Member] General and Administrative Expense [Member] Employees [Member]	Sep. 30, 2013 Stock Options And Warrants [Member] General and Administrative Expense [Member] Non-Employees [Member]	Sep. 30, 2012 Stock Options And Warrants [Member] General and Administrative Expense [Member] Non-Employees [Member]	Sep. 30, 2013 Stock Options And Warrants [Member] General and Administrative Expense [Member] Non-Employees [Member]	Sep. 30, 2012 Stock Options And Warrants [Member] General and Administrative Expense [Member] Non-Employees [Member]	Sep. 30, 2013 Stock Options And Warrants [Member] Minimum [Member]	Sep. 30, 2012 Stock Options And Warrants [Member] Minimum [Member]	Sep. 30, 2013 Stock Options And Warrants [Member] Maximum [Member]	Sep. 30, 2012 Stock Options And Warrants [Member] Maximum [Member]	Sep. 30, 2013 Restricted Stock [Member]	Sep. 30, 2012 Restricted Stock [Member]	Sep. 30, 2013 Restricted Stock [Member]	Sep. 30, 2012 Restricted Stock [Member]	Dec. 31, 2012 Restricted Stock [Member] Senior management [Member]	Sep. 30, 2013 2000 Long Term Incentive Plan [Member]	Sep. 30, 2013 2008 Stock Incentive Plan [Member]	Sep. 30, 2013 2008 Stock Incentive Plan [Member] Restricted Stock [Member] Senior management [Member]	Jun. 30, 2013 2008 Stock Incentive Plan [Member] Restricted Stock [Member] Senior management [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, shares subject to stock options (in shares)																																																					1,000,000	2,400,000
Expiration date																																																					Aug. 06, 2010
Share-based compensation, shares available for future grant (in shares)																																																					0	7,600,000
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Method Used										Black-Scholes option-pricing model
Risk-free interest rate (in hundredths)																		1.36%	0.61%
Expected volatility, Minimum (in hundredths)																		84.50%	85.80%
Expected volatility, Maximum (in hundredths)																		77.40%	97.70%
Expected lives															10 years																													5 years	4 years	6 years	10 years
Expected dividend yield (in hundredths)										0.00%									0.00%
Estimated annualized forfeiture rate (in hundredths)			12.00%	14.00%		3.00%	2.00%	0.00%	0.00%
Unrecognized compensation expense related to unvested stock options, granted					$ 1,200,000
Unrecognized compensation cost, recognized as expense over a weighted-average period	1 year 0 months 7 days
Number of Options (Employees and Non-Employees) [Abstract]
Outstanding at beginning of period (in shares)										3,382,993						3,240,850	142,143																																			100,000
Granted (in shares)										152,176						127,176	25,000
Exercised (in shares)										(476)						(476)	0
Forfeited or expired (in shares)										(127,812)						(127,812)	0
Outstanding at end of period (in shares)										3,406,881						3,239,738	167,143																																			100,000
Options exercisable at end of period (in shares)										2,432,243						2,274,029	158,214
Weighted-Average Exercise Price Options [Abstract]
Outstanding at beginning of period (in dollars per share)										$ 4.17
Granted (in dollars per share)										$ 2.69
Exercised (in dollars per share)										$ 1.96
Forfeited or expired (in dollars per share)										$ 3.09
Outstanding at end of period (in dollars per share)										$ 4.15
Options exercisable at end of period (in dollars per share)										$ 4.97
Number of Unvested Stock Options (Employees and Non-Employees) [Abstract]
Non-vested at beginning of period (in shares)										1,331,318						1,322,389	8,929
Granted, unvested stock options (in shares)										152,176						127,176	25,000
Forfeited or expired, unvested stock options (in shares)										(127,812)						(127,812)	0
Vested (in shares)										(381,044)						(356,044)	(25,000)
Non-vested at end of period (in shares)										974,638						965,709	8,929
Weighted average grant date fair value per share [Abstract]
Non-vested at beginning of period (in dollars per share)										$ 1.69
Granted, unvested stock options (in dollars per share)										$ 1.92
Forfeited or expired, unvested stock options (in dollars per share)										$ 2.31
Vested (in dollars per share)										$ 3.58
Non-vested at end of period (in dollars per share)										$ 1.66
Expected to vest (in shares)																																																								50,000
Expected to vest over subsequent period (in shares)																																																							50,000
Value of restricted shares issued																																																							186,900
Total stock-based compensation expense resulting from stock options and warrants [Abstract]
Allocated employee and non-employee stock-based compensation expense, Total																				255,319	273,106	746,303	903,551	271,594	177,617	450,880	406,109	52,492	95,715	156,247	289,081	0	0	0	0	202,827	177,391	590,056	614,470	271,594	177,617	450,880	406,109					47,006	0	139,484	0
Share-based compensation arrangement by share-based payment award, shares issued in period (in shares)										152,176								500,000
Share based compensation, shares authorized under significant ranges of outstanding stock option plans in period [Abstract]
Range of Exercise Prices, Lower Range (in dollars per share)											$ 1.83	$ 3.01	$ 7.01	$ 8.51
Range of Exercise Prices, Upper Range (in dollars per share)											$ 3.00	$ 7.00	$ 8.50	$ 32.55
Number of Options (in shares)										3,406,881	2,123,538	213,512	937,545	132,286
Weighted-Average Remaining Contractual Life										7 years 0 months 14 days	8 years 8 months 26 days	5 years 5 months 1 day	4 years 4 months 24 days	1 year 1 month 24 days
Weighted-Average Exercise Price (in dollars per share)										$ 4.15	$ 1.99	$ 4.91	$ 7.66	$ 12.75
Number of Options Exercisable (in shares)										2,432,243	1,212,265	176,036	911,656	132,286
Weighted-Average Remaining Contractual Life										7 years 0 months 14 days	8 years 8 months 26 days	5 years 5 months 1 day	4 years 4 months 24 days	1 year 1 month 24 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)										$ 4.97	$ 2.04	$ 5.26	$ 7.67	$ 12.75
The aggregate intrinsic value of outstanding options										$ 4,200,000
Closing price of the common stock (in dollars per share)										$ 3.23								$ 2.5
Warrants outstanding (in shares)	8,083,181	7,518,113