Income Taxes (Schedule of Credit Carryforward Amounts) (Details)

Income Taxes (Schedule of Credit Carryforward Amounts) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Tax Credit Carryforward [Line Items]
U.S. R&D credit carryforwards	8,394,408	$ 7,388,463
1998 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2018
1999 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2019
2000 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2020
2001 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2021
2002 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2022
2003 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2023
2004 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2024
2005 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2025
2006 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2026
2007 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2027
2008 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2028
2009 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2029
2010 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2030
2011 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2031
2012 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2032
2013 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2033
2014 [Member]
Tax Credit Carryforward [Line Items]
Expiration dates	Dec. 31, 2034
Domestic Tax Authority [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	153,105,438	118,500,000
U.S. R&D credit carryforwards	8,036,715	7,388,463
Domestic Tax Authority [Member] \| 1998 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	17,142,781
U.S. R&D credit carryforwards	1,173,387
Domestic Tax Authority [Member] \| 1999 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	0
U.S. R&D credit carryforwards	130,359
Domestic Tax Authority [Member] \| 2000 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	0
U.S. R&D credit carryforwards	71,713
Domestic Tax Authority [Member] \| 2001 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	0
U.S. R&D credit carryforwards	39,128
Domestic Tax Authority [Member] \| 2002 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	1,282,447
U.S. R&D credit carryforwards	5,350
Domestic Tax Authority [Member] \| 2003 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	337,714
U.S. R&D credit carryforwards	2,905
Domestic Tax Authority [Member] \| 2004 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	1,237,146
U.S. R&D credit carryforwards	22,861
Domestic Tax Authority [Member] \| 2005 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	3,246,062
U.S. R&D credit carryforwards	218,332
Domestic Tax Authority [Member] \| 2006 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	3,127,238
U.S. R&D credit carryforwards	365,541
Domestic Tax Authority [Member] \| 2007 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	2,863,443
U.S. R&D credit carryforwards	342,898
Domestic Tax Authority [Member] \| 2008 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	2,826,656
U.S. R&D credit carryforwards	531,539
Domestic Tax Authority [Member] \| 2009 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	13,753,769
U.S. R&D credit carryforwards	596,843
Domestic Tax Authority [Member] \| 2010 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	5,425,105
U.S. R&D credit carryforwards	1,094,449
Domestic Tax Authority [Member] \| 2011 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	1,904,744
U.S. R&D credit carryforwards	1,950,744
Domestic Tax Authority [Member] \| 2012 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	28,541,353
U.S. R&D credit carryforwards	468,008
Domestic Tax Authority [Member] \| 2013 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	36,840,453
U.S. R&D credit carryforwards	374,406
Domestic Tax Authority [Member] \| 2014 [Member]
Tax Credit Carryforward [Line Items]
U.S. Net Operating Loss Carryforwards	34,576,527
U.S. R&D credit carryforwards	648,252

Annual report pursuant to Section 13 and 15(d)

Income Taxes (Schedule of Credit Carryforward Amounts) (Details)