Issuance of Common Stock, Convertible Debt and Warrants (Details)							9 Months Ended
	Sep. 23, 2015 USD ($) day $ / shares shares	Jun. 01, 2015 USD ($) $ / shares shares	May. 21, 2015 USD ($) $ / shares shares	Jan. 26, 2015 USD ($) $ / shares shares	Jun. 11, 2014 USD ($) $ / shares shares	Jun. 01, 2014 USD ($) $ / shares shares	Sep. 30, 2015 USD ($) shares	Sep. 30, 2014 USD ($) $ / shares shares	Dec. 31, 2014 USD ($)
Common Stock
Net proceeds from issuance of convertible debt and warrants							$ 490,000	$ 0
Number of shares under warrants | shares							4,197,500
Warrant liability	$ 84,000		$ 1,846,900				$ 570,459		$ 0
Convertible Debt, due December 23, 2015	$ 406,000
Net proceeds from issuance of common stock and warrants							8,206,729	14,457,789
Proceeds from warrant exercises							0	121,862
Proceeds from issuance of shares under share-based compensation plans							$ 42,508	$ 99,495
Employee Stock Purchase Plan 2004 | Common Class A
Common Stock
Share price (in dollars per share) | $ / shares		$ 0.56				$ 0.94
Stock issued related to employee stock purchase plans | shares		75,773				105,454
Proceeds from issuance of shares under share-based compensation plans		$ 42,508				$ 99,495
Shelf Registration 2015
Common Stock
Number of shares issued | shares			7,300,000
Price per unit (in dollars per unit) | $ / shares			$ 0.65
Placement agent fees equal to gross proceeds from offering (as a percent)			7.00%
Net proceeds from issuance of units			$ 4,868,000
Underwriter fees			382,000
Legal and other fees			$ 207,000
Shelf Registration 2015 | Common Class A
Common Stock
Number of shares issued | shares				5,513,044
Unit components - number of shares in each unit | shares			1
Share price (in dollars per share) | $ / shares				$ 0.65
Gross proceeds from issuance of common stock				$ 3,583,479
Over-Allotment Option | Common Class A
Common Stock
Number of shares issued | shares			1,095,000
Shelf Registration 2013 | Common Class A
Common Stock
Number of shares issued | shares					5,225,560
Placement agent fees equal to gross proceeds from offering (as a percent)					7.00%
Legal and other fees					$ 159,000
Share price (in dollars per share) | $ / shares					$ 1.90
Gross proceeds from issuance of common stock					$ 9,928,564
Net proceeds from issuance of common stock and warrants					9,075,000
Placement agent fees					$ 695,000
At the Market Sales Agreement | Common Class A
Common Stock
Number of shares issued | shares								5,410,450
Net proceeds from issuance of common stock and warrants								$ 5,383,009
Offering costs								$ 172,000
At the Market Sales Agreement | Common Class A | Minimum
Common Stock
Share price (in dollars per share) | $ / shares								$ 0.90
At the Market Sales Agreement | Common Class A | Maximum
Common Stock
Share price (in dollars per share) | $ / shares								1.39
Warrants Issued September 2015
Common Stock
Number of shares under warrants | shares	1,225,000
Exercise price of warrants (in dollars per share) | $ / shares	$ 0.18
May 2015 Warrants
Common Stock
Exercise price of warrants (in dollars per share) | $ / shares			$ 0.81
Warrant liability			$ 1,846,900
May 2015 Warrants | Shelf Registration 2015
Common Stock
Number of common stock called by each warrant | shares			0.5
May 2015 Warrants | Over-Allotment Option
Common Stock
Exercise price of warrants (in dollars per share) | $ / shares	$ 0.07		$ 0.81
Number of warrants purchased | shares			547,500
Warrants January 2015 Subscribers | Common Class A
Common Stock
Number of shares under warrants | shares				2,205,216
Exercise price of warrants (in dollars per share) | $ / shares				$ 0.70
Placement agent fees equal to gross proceeds from offering (as a percent)				6.00%
Legal and other fees				$ 30,000
Net proceeds from issuance of common stock and warrants				3,338,000
Placement agent fees				$ 215,000
SRA Warrants January 2015 Financing | Common Class A
Common Stock
Number of shares under warrants | shares				330,783
Exercise price of warrants (in dollars per share) | $ / shares				$ 0.70
Warrants Issued June 2014 | Shelf Registration 2013 | Common Class A
Common Stock
Number of shares under warrants | shares					2,090,224
Exercise price of warrants (in dollars per share) | $ / shares					$ 1.90
Warrants December 2013 Investors | Common Class A
Common Stock
Exercise price of warrants (in dollars per share) | $ / shares								$ 0.91
Proceeds from warrant exercises								$ 121,862
Stock issued upon exercise of warrants | shares								133,914
Convertible Debt
Common Stock
Net proceeds from issuance of convertible debt and warrants	$ 490,000
Debt Instrument, Convertible, Expected to be Repaid or Converted to Stock	$ 588,000
Debt Instrument, Convertible, Conversion Price | $ / shares	$ 0.168
Debt Instrument, Convertible, Conversion Ratio	0.8
Number of threshold trading days | day	5
Convertible Debt | Maximum
Common Stock
Debt Instrument, Convertible, Number of Equity Instruments, Percentage Outstanding	19.90%