Fair Value Measurements (Schedule Of Financial Assets And Liabilities Measured At Fair Value) (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 5,497,788	$ 829,881
Current Liabilities, fair value	(770,041)	(1,002,623)
Assets (Liabilities) Net, fair value	22,805,682	23,346,369
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	5,497,788	829,881
Assets (Liabilities) Net, fair value	5,497,788	829,881
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets (Liabilities) Net, fair value	18,077,935	23,519,111
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current Liabilities, fair value	(770,041)	(1,002,623)
Assets (Liabilities) Net, fair value	(770,041)	(1,002,623)
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	5,497,788	829,881
Money Market Funds [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	5,497,788	829,881
Accrued Consideration [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current Liabilities, fair value	(770,041)	(1,002,623)
Accrued Consideration [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current Liabilities, fair value	(770,041)	(1,002,623)
Short-Term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	12,701,538	18,635,601
Short-Term Investments [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	12,701,538	18,635,601
Short-Term Investments [Member] | Certificates Of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	7,258,768	18,635,601
Short-Term Investments [Member] | Certificates Of Deposit [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	7,258,768	18,635,601
Short-Term Investments [Member] | Corporate Notes And Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	3,800,143
Short-Term Investments [Member] | Corporate Notes And Bonds [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	3,800,143
Short-Term Investments [Member] | Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	1,642,627
Short-Term Investments [Member] | Commercial Paper [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	1,642,627
Long Term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	5,376,397	4,883,510
Long Term Investments [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	5,376,397	4,883,510
Long Term Investments [Member] | Certificates Of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	900,763	4,883,510
Long Term Investments [Member] | Certificates Of Deposit [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	900,763	4,883,510
Long Term Investments [Member] | Corporate Notes And Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	4,475,634
Long Term Investments [Member] | Corporate Notes And Bonds [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 4,475,634