Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Reconciliation Of Changes In The Fair Value Of Liabilities) (Details)

v2.4.1.9
Fair Value Measurements (Reconciliation Of Changes In The Fair Value Of Liabilities) (Details) (Warrant Liabilities [Member], USD $)
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Warrant Liabilities [Member]
   
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Balance at January 1 $ 3,768,351us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue
/ us-gaap_FairValueByLiabilityClassAxis
= rnn_WarrantLiabilitiesMember
$ 5,034,058us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue
/ us-gaap_FairValueByLiabilityClassAxis
= rnn_WarrantLiabilitiesMember
Additions   3,691,429us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityPurchases
/ us-gaap_FairValueByLiabilityClassAxis
= rnn_WarrantLiabilitiesMember
Unrealized (gains)/losses, net (115,415)rnn_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityUnrealizedLosses
/ us-gaap_FairValueByLiabilityClassAxis
= rnn_WarrantLiabilitiesMember
11,660,524rnn_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityUnrealizedLosses
/ us-gaap_FairValueByLiabilityClassAxis
= rnn_WarrantLiabilitiesMember
Transfers out of level 3   (9,095,445)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationLiabilityTransfersOutOfLevel3
/ us-gaap_FairValueByLiabilityClassAxis
= rnn_WarrantLiabilitiesMember
Balance at March 31 $ 3,652,936us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue
/ us-gaap_FairValueByLiabilityClassAxis
= rnn_WarrantLiabilitiesMember
$ 11,290,566us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue
/ us-gaap_FairValueByLiabilityClassAxis
= rnn_WarrantLiabilitiesMember