(4) Fair Value Measurements (Details) (USD $)	Jun. 30, 2013	Dec. 31, 2012
Cash equivalents:
Total cash equivalents	$ 5,501,965	$ 4,285,309
Marketable securities:
Total marketable securities	7,838,590	10,530,942
Total assets measured at fair value	13,340,555	14,816,251
Fair Value, Inputs, Level 1
Cash equivalents:
Total cash equivalents	5,501,965	4,285,309
Marketable securities:
Total assets measured at fair value	5,501,965	4,285,309
Fair Value, Inputs, Level 2
Marketable securities:
Total marketable securities	7,838,590	10,530,942
Total assets measured at fair value	7,838,590	10,530,942
Money Market Funds
Cash equivalents:
Total cash equivalents	5,501,965	4,285,309
Money Market Funds | Fair Value, Inputs, Level 1
Cash equivalents:
Total cash equivalents	5,501,965	4,285,309
Money Market Funds | Fair Value, Inputs, Level 2
Cash equivalents:
Total cash equivalents	0	0
Money Market Funds | Fair Value, Inputs, Level 3
Cash equivalents:
Total cash equivalents	0	0
Corporate Debt Securities Member
Marketable securities:
Total marketable securities	7,838,590	10,530,942
Corporate Debt Securities Member | Fair Value, Inputs, Level 1
Marketable securities:
Total marketable securities	0	0
Corporate Debt Securities Member | Fair Value, Inputs, Level 2
Marketable securities:
Total marketable securities	7,838,590	10,530,942
Corporate Debt Securities Member | Fair Value, Inputs, Level 3
Marketable securities:
Total marketable securities	$ 0	$ 0