Fair Value of Financial Instruments - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Cash and Cash Equivalents | Money Market Securities
Asset included in:
Financial Assets	$ 9,666,594	$ 3,608,890
Cash and Cash Equivalents | Corporate Debt Securities
Asset included in:
Financial Assets	1,499,462
Investments at Fair Value | Corporate Debt Securities
Asset included in:
Financial Assets	14,844,827
Investments at Fair Value | US Government Obligations
Asset included in:
Financial Assets	3,307,680
Investments at Fair Value | US Government Agency Obligations
Asset included in:
Financial Assets	14,717,062
Level 1 | Cash and Cash Equivalents | Money Market Securities
Asset included in:
Financial Assets	9,666,594	3,608,890
Level 1 | Investments at Fair Value | US Government Obligations
Asset included in:
Financial Assets	3,307,680
Level 2 | Cash and Cash Equivalents | Corporate Debt Securities
Asset included in:
Financial Assets	1,499,462
Level 2 | Investments at Fair Value | Corporate Debt Securities
Asset included in:
Financial Assets	14,844,827
Level 2 | Investments at Fair Value | US Government Agency Obligations
Asset included in:
Financial Assets	$ 14,717,062
Preferred Stock Warrants
Liabilities:
Financial Liabilities		429,035
Preferred Stock Warrants | Level 3
Liabilities:
Financial Liabilities		429,035
Warrant
Liabilities:
Financial Liabilities		301,508
Warrant | Level 3
Liabilities:
Financial Liabilities		$ 301,508