Common Stock Offerings (Details Textual) (USD $)	1 Months Ended													12 Months Ended			141 Months Ended
	Nov. 30, 2013	Nov. 30, 2012	Jan. 31, 2012	Feb. 28, 2011	Oct. 31, 2010	Sep. 30, 2010	Mar. 31, 2010	Jul. 31, 2009	Nov. 30, 2007	Mar. 31, 2007	May 31, 2006	Feb. 28, 2006	Feb. 28, 2005	Dec. 31, 2013	Dec. 31, 2006	Dec. 31, 2004	Dec. 31, 2013	Dec. 31, 2012	Feb. 29, 2012	Jul. 31, 2010
Common Stock Offerings [Line Items]
Proceeds from Issuance of Common Stock	$ 23,000,000		$ 23,700,000	$ 40,300,000	$ 40,300,000	$ 2,900,000	$ 18,200,000	$ 13,300,000	$ 48,900,000	$ 12,500,000				$ 10,900,000	$ 21,500,000	$ 14,500,000
Common stock issued during period, shares	7,666,667		4,989,275	10,062,500	8,214,286	634,500	6,700,000	3,325,000	7,388,172	2,648,306				3,609,595	7,166,666	5,532,994
Stock Authorized Under Shelf Registration			63,950,000	63,950,000	61,566,686			62,218,060											100,000,000
Common Stock, Shares, Available For Issuance																				3,000,000
Proceeds From Equity Issuance, Per Share Amount						$ 4.49
Warrants Issued To Purchase Common Stock, Shares							2,345,000			794,492		716,666		1,286,764	2,149,999	483,701
Warrant Fair Value							3,900,000			1,300,000		700,000			1,100,000	14,000
Common stock, par value (in dollars per share)							$ 2.79			$ 5.66		$ 3.30		$ 0.0001	$ 4.20	$ 2.88	$ 0.0001	$ 0.0001
Payments of Stock Issuance Costs	1,600,000		1,600,000	2,500,000			1,500,000	900,000	3,200,000	1,000,000		1,600,000		500,000		1,000,000
Value Of Common Stock Sold, Percentage												110.00%
Warrant, Expiration Period												7 years				7 years
Debt Conversion, Converted Instrument, Amount																1,700,000
Common stock issued in conversion of loan																677,919
Sale Of Shares Aggregate Offering Price Maximum Limit		20,000,000
Proceeds From Issuance Of Common Stock, Net	$ 21,400,000													$ 10,400,000
Volume Weighted Average Closing Bid Price Common Stock										$ 12.00					$ 9.00
Stock Issued During Period, New Issues, per share														$ 3.02