Stock Based Compensation (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Unrecognized compensation cost, recognized as expense over a weighted-average period			1 year 1 month 17 days
Employees [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Estimated annualized forfeiture rate (in hundredths)			12.00%	14.00%
Employees and Directors [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Unrecognized compensation expense related to unvested stock options, granted	$ 1,300,000		$ 1,300,000
Senior management [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Estimated annualized forfeiture rate (in hundredths)			3.00%	2.00%
Directors and nonemployees [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Estimated annualized forfeiture rate (in hundredths)			0.00%	0.00%
Stock Options [Member]
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)			1.11%	1.54%
Expected volatility, Minimum (in hundredths)			85.20%	89.70%
Expected volatility, Maximum (in hundredths)			85.80%	97.70%
Expected lives			6 years
Expected dividend yield (in hundredths)			0.00%	0.00%
Number of Options (Employees and Non-Employees) [Abstract]
Outstanding at beginning of period (in shares)			3,382,993
Granted (in shares)			117,176
Exercised (in shares)			(476)
Forfeited or expired (in shares)			(103,716)
Outstanding at end of period (in shares)	3,395,977		3,395,977
Options exercisable at end of period (in shares)	2,309,361		2,309,361
Weighted-Average Exercise Price Options [Abstract]
Outstanding at beginning of period (in dollars per share)			$ 4.17
Granted (in dollars per share)			$ 2.52
Exercised (in dollars per share)			$ 1.96
Forfeited or expired (in dollars per share)			$ 3.08
Outstanding at end of period (in dollars per share)	$ 4.15		$ 4.15
Options exercisable at end of period (in dollars per share)	$ 5.10		$ 5.10
Number of Unvested Stock Options (Employees and Non-Employees) [Abstract]
Non-vested at beginning of period (in shares)			1,331,318
Granted, unvested stock options (in shares)			117,176
Forfeited or expired, unvested stock options (in shares)			(103,716)
Vested (in shares)			(258,162)
Non-vested at end of period (in shares)	1,086,616		1,086,616
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)			$ 1.80
Forfeited or expired, unvested stock options (in dollars per share)			$ 2.32
Vested (in dollars per share)			$ 3.68
Non-vested at end of period (in dollars per share)	$ 1.67		$ 1.67
Total stock-based compensation expense resulting from stock options and warrants [Abstract]
Share-based compensation arrangement by share-based payment award, shares issued in period (in shares)			117,176
Share based compensation, shares authorized under significant ranges of outstanding stock option plans in period [Abstract]
Number of Options (in shares)	3,395,977		3,395,977
Weighted-Average Remaining Contractual Life			7 years 3 months 4 days
Weighted-Average Exercise Price (in dollars per share)	$ 4.15		$ 4.15
Number of Options Exercisable (in shares)	2,309,361		2,309,361
Weighted-Average Contractual Life			7 years 3 months 4 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)	$ 5.10		$ 5.10
The aggregate intrinsic value of outstanding options	2,700,000		2,700,000
Closing price of the common stock (in dollars per share)	$ 2.00		$ 2.00
Stock Options [Member] | Range $ 1.83 - 3.00 [Member]
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
Range of Exercise Prices, Upper Range (in dollars per share)			$ 3.00
Number of Options (in shares)	2,143,069		2,143,069
Weighted-Average Remaining Contractual Life			8 years 11 months 26 days
Weighted-Average Exercise Price (in dollars per share)	$ 1.99		$ 1.99
Number of Options Exercisable (in shares)	1,100,587		1,100,587
Weighted-Average Contractual Life			8 years 11 months 26 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)	$ 2.04		$ 2.04
Stock Options [Member] | Range $ 3.01 - 7.00 [Member]
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)			$ 3.01
Range of Exercise Prices, Upper Range (in dollars per share)			$ 7.00
Number of Options (in shares)	178,512		178,512
Weighted-Average Remaining Contractual Life			4 years 9 months 7 days
Weighted-Average Exercise Price (in dollars per share)	$ 5.24		$ 5.24
Number of Options Exercisable (in shares)	176,036		176,036
Weighted-Average Contractual Life			4 years 9 months 7 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)	$ 5.26		$ 5.26
Stock Options [Member] | Range $ 7.01 - 8.50 [Member]
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)			$ 7.01
Range of Exercise Prices, Upper Range (in dollars per share)			$ 8.50
Number of Options (in shares)	942,110		942,110
Weighted-Average Remaining Contractual Life			4 years 7 months 17 days
Weighted-Average Exercise Price (in dollars per share)	$ 7.66		$ 7.66
Number of Options Exercisable (in shares)	900,452		900,452
Weighted-Average Contractual Life			4 years 7 months 17 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)	$ 7.68		$ 7.68
Stock Options [Member] | Range $ 8.51 - 32.55 [Member]
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)			$ 8.51
Range of Exercise Prices, Upper Range (in dollars per share)			$ 32.55
Number of Options (in shares)	132,286		132,286
Weighted-Average Remaining Contractual Life			1 year 3 months 29 days
Weighted-Average Exercise Price (in dollars per share)	$ 12.75		$ 12.75
Number of Options Exercisable (in shares)	132,286		132,286
Weighted-Average Contractual Life			1 year 3 months 29 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share)	$ 12.75		$ 12.75
Stock Options [Member] | Minimum [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Expected lives				6 years
Stock Options [Member] | Maximum [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Expected lives			10 years	10 years
Stock Options [Member] | Employees [Member]
Number of Options (Employees and Non-Employees) [Abstract]
Outstanding at beginning of period (in shares)			3,240,850
Granted (in shares)			92,176
Exercised (in shares)			(476)
Forfeited or expired (in shares)			(103,716)
Outstanding at end of period (in shares)	3,228,834		3,228,834
Options exercisable at end of period (in shares)	2,159,480		2,159,480
Number of Unvested Stock Options (Employees and Non-Employees) [Abstract]
Non-vested at beginning of period (in shares)			1,322,389
Granted, unvested stock options (in shares)			92,176
Forfeited or expired, unvested stock options (in shares)			(103,716)
Vested (in shares)			(241,495)
Non-vested at end of period (in shares)	1,069,356		1,069,356
Stock Options [Member] | Non employees [Member]
Number of Options (Employees and Non-Employees) [Abstract]
Outstanding at beginning of period (in shares)			142,143
Granted (in shares)			25,000
Exercised (in shares)			0
Forfeited or expired (in shares)			0
Outstanding at end of period (in shares)	167,143		167,143
Options exercisable at end of period (in shares)	149,881		149,881
Number of Unvested Stock Options (Employees and Non-Employees) [Abstract]
Non-vested at beginning of period (in shares)			8,929
Granted, unvested stock options (in shares)			25,000
Forfeited or expired, unvested stock options (in shares)			0
Vested (in shares)			(16,667)
Non-vested at end of period (in shares)	17,262		17,262
Stock Options And Warrants [Member] | Employees [Member]
Total stock-based compensation expense resulting from stock options and warrants [Abstract]
Allocated employee and non-employee stock-based compensation expense, Total	256,172	361,249	490,984	630,445
Stock Options And Warrants [Member] | Non-Employees [Member]
Total stock-based compensation expense resulting from stock options and warrants [Abstract]
Allocated employee and non-employee stock-based compensation expense, Total	152,074	176,074	179,286	228,492
Stock Options And Warrants [Member] | Research and Development Expense [Member] | Employees [Member]
Total stock-based compensation expense resulting from stock options and warrants [Abstract]
Allocated employee and non-employee stock-based compensation expense, Total	53,583	98,242	103,755	193,366
Stock Options And Warrants [Member] | Research and Development Expense [Member] | Non-Employees [Member]
Total stock-based compensation expense resulting from stock options and warrants [Abstract]
Allocated employee and non-employee stock-based compensation expense, Total	0	0	0	0
Stock Options And Warrants [Member] | General and Administrative Expense [Member] | Employees [Member]
Total stock-based compensation expense resulting from stock options and warrants [Abstract]
Allocated employee and non-employee stock-based compensation expense, Total	202,589	263,007	387,229	437,079
Stock Options And Warrants [Member] | General and Administrative Expense [Member] | Non-Employees [Member]
Total stock-based compensation expense resulting from stock options and warrants [Abstract]
Allocated employee and non-employee stock-based compensation expense, Total	152,074	176,074	179,286	228,492
Restricted Stock [Member]
Number of Options (Employees and Non-Employees) [Abstract]
Outstanding at end of period (in shares)	100,000		100,000
Number of Unvested Stock Options (Employees and Non-Employees) [Abstract]
Granted, unvested stock options (in shares)			100,000
Total stock-based compensation expense resulting from stock options and warrants [Abstract]
Allocated employee and non-employee stock-based compensation expense, Total	46,495	0	92,478	0
2000 Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)	1,400,000		1,400,000
Share-based compensation, shares subject to stock options (in shares)	1,000,000		1,000,000
Expiration date			Aug. 06, 2010
Share-based compensation, shares available for future grant (in shares)	0		0
2008 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)	5,000,000		5,000,000
Share-based compensation, shares subject to stock options (in shares)	2,400,000		2,400,000
Share-based compensation, shares available for future grant (in shares)	2,600,000		2,600,000
2008 Stock Incentive Plan [Member] | Restricted Stock [Member]
Weighted average grant date fair value per share [Abstract]
Expected to vest (in shares)	50,000		50,000
Expected to vest over subsequent period (in shares)	50,000		50,000
Value of restricted shares issued	$ 186,900		$ 186,900