Consolidated Statements of Change in Stockholders' Equity (USD $)	Preferred Stock [Member]	Preferred Stock [Member] Common Stock [Member]	Preferred Stock [Member] Additional Paid-in Capital [Member]	Series A Redeemable Convertible Preferred Stock [Member] Additional Paid-in Capital [Member]	Series A Redeemable Convertible Preferred Stock [Member]	Hercules Warrant [Member] Additional Paid-in Capital [Member]	Hercules Warrant [Member]	Common Stock Warrants (Member) Common Stock [Member]	Common Stock Warrants (Member) Additional Paid-in Capital [Member]	Common Stock Warrants (Member)	Direct and ATM [Member] Common Stock [Member]	Direct and ATM [Member] Additional Paid-in Capital [Member]	Direct and ATM [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Total
Balance at December 31 at Dec. 31, 2011															$ 75,332	$ 158,887,403	$ (2,884,125)	$ (267,700)	$ (129,608,341)	$ 26,193,568
Balance at December 31 (in Shares) at Dec. 31, 2011															7,374,739		158,384
Net loss																			(26,568,382)	(26,568,382)
Unrealized gain on investments available for sale																		150,093		150,093
Valuation of common stock warrants in connection with notes payable				73,654	73,654
Conversion of convertible securities								8,455	10,156,437	10,164,892
Conversion of convertible securities (in Shares)								845,526												847,715
Stock-based compensation expense																1,143,764				1,143,764
Issuance of restricted stock and option exercise															586	696,643				697,220
Issuance of restricted stock and option exercise (in Shares)															58,618
Issuance of common stock out of treasury																	193,614		(86,565)	107,049
Issuance of common stock out of treasury (in Shares)															10,624		(10,624)
Balance at December 31 at Dec. 31, 2012															84,373	170,957,891	(2,690,511)	(126,607)	(156,263,288)	11,961,858
Balance at December 31 (in Shares) at Dec. 31, 2012															8,289,507		147,760			729,825
Net loss																			(8,251,358)	(8,251,358)
Stock issued, new issues											25,880	15,598,670	15,624,550	150		18,217,702				18,217,852
Stock issued, new issues (in Shares)											2,588,032			15,001
Classification of warrants to/from common stock warrant liability, net																(3,809,730)				(3,809,730)
Non-cash dividend on beneficial conversion feature associated with the preferred stock offering																			(4,601,410)	(4,601,410)
Unrealized gain on investments available for sale																		82,441		82,441
Valuation of common stock warrants in connection with notes payable				521,763	521,763
Conversion of convertible securities	(150)	26,828	(26,678)					180	261,764	261,944
Conversion of convertible securities (in Shares)	(15,001)	2,682,759						18,021												15,833
Stock-based compensation expense																1,235,437				1,235,437
Issuance of restricted stock and option exercise															129	183,918				184,047
Issuance of restricted stock and option exercise (in Shares)															12,872
Issuance of common stock out of treasury																	269,147		(171,101)	98,046
Issuance of common stock out of treasury (in Shares)															14,765		(14,765)
Fractional share payment															(10)	(1,595)				(1,605)
Fractional share payment (in Shares)															(981)
Balance at December 31 at Dec. 31, 2013															137,380	203,139,142	(2,421,364)	(44,166)	(169,287,157)	31,523,835
Balance at December 31 (in Shares) at Dec. 31, 2013															13,604,975		132,995			863,462
Net loss																			(25,494,273)	(25,494,273)
Stock issued, new issues											36,036	13,752,775	13,788,811
Stock issued, new issues (in Shares)											3,603,604
Common stock issued in connection with the acquisition of EGEN, Inc. assets															27,122	10,823,855				10,850,977
Common stock issued in connection with the acquisition of EGEN, Inc. assets (in Shares)															2,712,188
Unrealized gain on investments available for sale																		28,134		28,134
Valuation of common stock warrants in connection with notes payable						(521,763)	(521,763)
Stock-based compensation expense																2,513,042				2,513,042
Issuance of restricted stock and option exercise															438	71,652				72,090
Issuance of restricted stock and option exercise (in Shares)															43,841
Issuance of common stock out of treasury																	356,755		(292,272)	64,483
Issuance of common stock out of treasury (in Shares)															19,595		(19,595)
Balance at December 31 at Dec. 31, 2014															$ 200,976	$ 229,778,703	$ (2,064,609)	$ (16,032)	$ (195,073,702)	$ 32,825,336
Balance at December 31 (in Shares) at Dec. 31, 2014															19,984,203		113,400			1,751,773