Stock Based Compensation (Details)				3 Months Ended		9 Months Ended
	Jul. 06, 2015 shares	Dec. 20, 2013 $ / shares	Dec. 10, 2013 $ / shares	Sep. 30, 2015 USD ($) $ / shares shares	Sep. 30, 2014 USD ($) $ / shares	Sep. 30, 2015 USD ($) $ / shares shares	Sep. 30, 2014 USD ($) $ / shares shares	Jul. 24, 2015 $ / shares	Dec. 31, 2014 $ / shares shares	Feb. 05, 2014 $ / shares
Weighted-Average Exercise Price Options [Abstract]
Exercised (in dollars per share) | $ / shares		$ 4.66	$ 2.39
Share-based compensation arrangement by share-based payment award, shares issued in period (in shares)	287,143
Share based compensation, shares authorized under significant ranges of outstanding stock option plans in period [Abstract]
Closing price of the common stock (in dollars per share) | $ / shares								$ 2.75		$ 6.50
Employees [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Estimated annualized forfeiture rate						10.00%	12.00%
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 | $				$ 4,200,000		$ 4,200,000
Unrecognized compensation cost, recognized as expense over a weighted-average period						10 months 28 days
Senior Management [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Estimated annualized forfeiture rate						2.00%	2.00%
Directors and Non-employees [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Estimated annualized forfeiture rate						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
Contractual term						10 years
Number of Options (Employees and Non-Employees) [Abstract]
Outstanding at beginning of period (in shares)						10,040,735
Granted (in shares)						550,000	362,500
Exercised (in shares)						(287,143)
Expired (in shares)						(134,016)
Outstanding at end of period (in shares)				10,169,576		10,169,576
Options exercisable at end of period (in shares)				7,090,478		7,090,478
Weighted-Average Exercise Price Options [Abstract]
Outstanding at beginning of period (in dollars per share) | $ / shares						$ 2.87
Granted (in dollars per share) | $ / shares						3.86
Exercised (in dollars per share) | $ / shares						2.05
Expired (in dollars per share) | $ / shares						6.82
Outstanding at end of period (in dollars per share) | $ / shares				$ 3.36		3.36
Options exercisable at end of period (in dollars per share) | $ / shares				$ 3.61		$ 3.61
Share based compensation, shares authorized under significant ranges of outstanding stock option plans in period [Abstract]
Total Number of Options (in shares)				10,169,576		10,169,576
Weighted-Average Remaining Contractual Life						7 years 10 months 24 days
Weighted-Average Exercise Price (in dollars per share) | $ / shares				$ 3.36		$ 3.36
Total Number of Options Exercisable (in shares)				7,090,478		7,090,478
Weighted-Average Remaining Contractual Life						7 years 6 months 22 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share) | $ / shares				$ 3.61		$ 3.61
The aggregate intrinsic value of outstanding options | $				$ 1,400,000		$ 1,400,000
Aggregate intrinsic value of options vested | $						$ 900,000
Closing price of the common stock (in dollars per share) | $ / shares				$ 2.37		$ 2.37
Stock Options [Member] | Employees [Member]
Number of Options (Employees and Non-Employees) [Abstract]
Outstanding at beginning of period (in shares)						9,348,592
Granted (in shares)						550,000
Exercised (in shares)						(287,143)
Expired (in shares)						(77,587)
Outstanding at end of period (in shares)				9,533,862		9,533,862
Options exercisable at end of period (in shares)				6,454,764		6,454,764
Stock Options [Member] | Non-Employees [Member]
Number of Options (Employees and Non-Employees) [Abstract]
Outstanding at beginning of period (in shares)						692,143
Granted (in shares)						0
Exercised (in shares)						0
Expired (in shares)						(56,429)
Outstanding at end of period (in shares)				635,714		635,714
Options exercisable at end of period (in shares)				635,714		635,714
Stock Options and Warrants [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Risk-free interest rate						2.21%	1.98%
Expected dividend yield						0.00%	0.00%
Stock Options and Warrants [Member] | Minimum [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Expected volatility						78.20%	83.90%
Expected lives						6 years	6 years
Stock Options and Warrants [Member] | Maximum [Member]
Share-based compensation arrangement by share-based payment award, fair value assumptions and methodology [Abstract]
Expected volatility						84.40%	89.60%
Expected lives						10 years	10 years
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 | $				$ 885,246	$ 593,454	$ 4,313,870	$ 1,640,431
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 | $				(27,647)	24,228	206,437	463,388
Restricted Stock [Member]
Total stock-based compensation expense resulting from stock options and warrants [Abstract]
Allocated employee and non-employee stock-based compensation expense, Total | $				$ 0	$ 158,013	$ 0	$ 468,887
Warrants [Member]
Weighted-Average Exercise Price Options [Abstract]
Share-based compensation arrangement by share-based payment award, shares issued in period (in shares)							25,000
Exercise price of warrants (in dollars per share) | $ / shares					$ 5.60		$ 5.60
Share based compensation, shares authorized under significant ranges of outstanding stock option plans in period [Abstract]
Warrants outstanding (in shares)				7,225,472		7,225,472			7,349,760
Weighted-average exercise price of warrants outstanding (in dollars per share) | $ / shares				4.28		4.28			4.27
Range $1.83 - 2.50 [Member] | Stock Options [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) | $ / shares						$ 1.83
Range of Exercise Prices, Upper Range (in dollars per share) | $ / shares						$ 2.50
Total Number of Options (in shares)				5,557,558		5,557,558
Weighted-Average Remaining Contractual Life						8 years 2 months 26 days
Weighted-Average Exercise Price (in dollars per share) | $ / shares				$ 2.13		$ 2.13
Total Number of Options Exercisable (in shares)				3,242,079		3,242,079
Weighted-Average Remaining Contractual Life						7 years 9 months
Weighted-Average Exercise Price, Options Exercisable (in dollars per share) | $ / shares				$ 2.09		$ 2.09
Range $2.51 - 3.50 [Member] | Stock Options [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) | $ / shares						2.51
Range of Exercise Prices, Upper Range (in dollars per share) | $ / shares						$ 3.50
Total Number of Options (in shares)				947,339		947,339
Weighted-Average Remaining Contractual Life						8 years 4 months 28 days
Weighted-Average Exercise Price (in dollars per share) | $ / shares				$ 2.85		$ 2.85
Total Number of Options Exercisable (in shares)				897,340		897,340
Weighted-Average Remaining Contractual Life						8 years 4 months 20 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share) | $ / shares				$ 2.84		$ 2.84
Range $3.51 - 8.00 [Member] | Stock Options [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) | $ / shares						3.51
Range of Exercise Prices, Upper Range (in dollars per share) | $ / shares						$ 8.00
Total Number of Options (in shares)				3,376,614		3,376,614
Weighted-Average Remaining Contractual Life						7 years 8 months 12 days
Weighted-Average Exercise Price (in dollars per share) | $ / shares				$ 5.06		$ 5.06
Total Number of Options Exercisable (in shares)				2,662,994		2,662,994
Weighted-Average Remaining Contractual Life						7 years 6 months 18 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share) | $ / shares				$ 5.13		$ 5.13
Range $8.01 - 32.55 [Member] | Stock Options [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) | $ / shares						8.01
Range of Exercise Prices, Upper Range (in dollars per share) | $ / shares						$ 32.55
Total Number of Options (in shares)				288,065		288,065
Weighted-Average Remaining Contractual Life						2 years 22 days
Weighted-Average Exercise Price (in dollars per share) | $ / shares				$ 9.00		$ 9.00
Total Number of Options Exercisable (in shares)				288,065		288,065
Weighted-Average Remaining Contractual Life						2 years 22 days
Weighted-Average Exercise Price, Options Exercisable (in dollars per share) | $ / shares				$ 9.00		$ 9.00
Research and Development Expense [Member] | 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 | $				$ 402,292	$ 213,180	$ 1,131,072	$ 622,818
Research and Development Expense [Member] | 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 | $				0	0	0	86,539
General and Administrative Expense [Member] | 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 | $				482,954	380,274	3,182,798	1,017,613
General and Administrative Expense [Member] | 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 | $				$ (27,647)	$ 24,228	$ 206,437	$ 376,849
2000 Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, shares subject to stock options (in shares)				600,000		600,000
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]
Share-based compensation, shares subject to stock options (in shares)				9,600,000		9,600,000
Share-based compensation, shares available for future grant (in shares)				10,200,000		10,200,000
2008 Stock Incentive Plan [Member] | Restricted Stock [Member] | Senior Management [Member]
Weighted-Average Exercise Price Options [Abstract]
Restricted stock granted (in shares)						100,000
Value of restricted shares issued | $				$ 627,000		$ 627,000