(4) Fair Value Measurements (Details) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Cash equivalents:
Total cash equivalents	$ 5,002,654	$ 4,285,309
Marketable securities:
Total marketable securities	9,805,890	10,530,942
Total assets measured at fair value	14,808,544	14,816,251
Money Market Funds
Cash equivalents:
Total cash equivalents	5,002,654	4,285,309
Corporate Debt Securities Member
Marketable securities:
Total marketable securities	9,805,890	10,530,942
Fair Value, Inputs, Level 1
Marketable securities:
Total assets measured at fair value	5,002,654	4,285,309
Fair Value, Inputs, Level 1 | Money Market Funds
Cash equivalents:
Total cash equivalents	5,002,654	4,285,309
Fair Value, Inputs, Level 1 | Corporate Debt Securities Member
Marketable securities:
Total marketable securities	0	0
Fair Value, Inputs, Level 2
Marketable securities:
Total assets measured at fair value	9,805,890	10,530,942
Fair Value, Inputs, Level 2 | Money Market Funds
Cash equivalents:
Total cash equivalents	0	0
Fair Value, Inputs, Level 2 | Corporate Debt Securities Member
Marketable securities:
Total marketable securities	9,805,890	10,530,942
Level 3 Member | Money Market Funds
Cash equivalents:
Total cash equivalents	0	0
Level 3 Member | Corporate Debt Securities Member
Marketable securities:
Total marketable securities	$ 0	$ 0