Fair Value Measurements (Details) (Fair Value, Measurements, Recurring [Member], USD $)	Dec. 31, 2012	Dec. 31, 2011
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	$ 20,690,939	$ 38,365,818
Liabilities, fair value	2,859,899	5,176,319
Using Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	12,389,738	25,402,398
Liabilities, fair value	0	0
Using Significant Other Unobservable Inputs (Level 2) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	8,034,001	12,863,420
Liabilities, fair value	0	0
Using Significant Unobservable Inputs (Level 3) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	267,200	100,000
Liabilities, fair value	2,859,899	5,176,319
Money market funds [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	1,686,406	16,330,885
Money market funds [Member] \| Using Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	1,686,406	16,330,885
Money market funds [Member] \| Using Significant Other Unobservable Inputs (Level 2) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value		0
Money market funds [Member] \| Using Significant Unobservable Inputs (Level 3) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	0	0
Mutual funds [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	7,583,931	6,037,115
Mutual funds [Member] \| Using Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	0	0
Mutual funds [Member] \| Using Significant Other Unobservable Inputs (Level 2) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	7,583,931	6,037,115
Mutual funds [Member] \| Using Significant Unobservable Inputs (Level 3) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	0	0
Certificates of deposit [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	250,000	5,768,304
Certificates of deposit [Member] \| Using Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	0	0
Certificates of deposit [Member] \| Using Significant Other Unobservable Inputs (Level 2) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	250,000	5,768,304
Certificates of deposit [Member] \| Using Significant Unobservable Inputs (Level 3) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	0	0
Municipal bonds [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	200,070	1,058,001
Municipal bonds [Member] \| Using Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	0	0
Municipal bonds [Member] \| Using Significant Other Unobservable Inputs (Level 2) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	200,070	1,058,001
Municipal bonds [Member] \| Using Significant Unobservable Inputs (Level 3) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	0	0
Investment in affiliated entity [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	10,703,332	9,071,513
Investment in affiliated entity [Member] \| Using Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	10,703,332	9,071,513
Investment in affiliated entity [Member] \| Using Significant Other Unobservable Inputs (Level 2) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	0	0
Investment in affiliated entity [Member] \| Using Significant Unobservable Inputs (Level 3) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	0	0
Common stock warrants [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	267,200	100,000
Liabilities, fair value	2,859,899	5,176,319
Common stock warrants [Member] \| Using Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	0	0
Liabilities, fair value	0	0
Common stock warrants [Member] \| Using Significant Other Unobservable Inputs (Level 2) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	0	0
Liabilities, fair value	0	0
Common stock warrants [Member] \| Using Significant Unobservable Inputs (Level 3) [Member]
Financial assets and liabilities that are measured at fair value on recurring basis
Assets, fair value	267,200	100,000
Liabilities, fair value	$ 2,859,899	$ 5,176,319