Annual report pursuant to Section 13 and 15(d)

Marketable Securities (Schedule Of Cost And Fair Value By Contractual Maturity) (Details)

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Marketable Securities (Schedule Of Cost And Fair Value By Contractual Maturity) (Details) (USD $)
Dec. 31, 2014
Marketable Securities [Abstract]  
Less than 1 year, Cost Basis, Maturity $ 17,023,001rnn_AvailableForSaleSecuritiesDebtMaturitiesRemainingFiscalYearAmortizedCostBasis
Less than 1 year, Fair Value, Maturity 17,010,586rnn_AvailableForSaleSecuritiesDebtMaturitiesRemainingFiscalYearFairValue
1 to 5 years, Cost Basis, Maturity 5,882,697rnn_AvailableForSaleSecuritiesDebtMaturitiesYearOneThroughFiveAmortizedCostBasis
1 to 5 years, Fair Value, Maturity 5,861,465rnn_AvailableForSaleSecuritiesDebtMaturitiesYearOneThroughFiveFairValue
Total Marketable Securities, Cost Basis, Maturity 22,905,698us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
Total Marketable Securities, Fair Value, Maturity $ 22,872,051us-gaap_AvailableForSaleSecuritiesDebtSecurities