Nature of Business (Details) (USD $)
12 Months Ended
Dec. 31, 2014
Program
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Nature of Business [Abstract]        
Number of programs in clinical development for cancer indications 2      
Estimated Projected Expenditure Type [Line Items]        
Cash and cash equivalents $ 32,218,905 $ 11,483,112 $ 14,344,088 $ 17,988,590
Short-term investments 45,621,593 27,084,980    
Projected expenditures for clinical programs 58,600,000      
Aldoxorubicin [Member]        
Estimated Projected Expenditure Type [Line Items]        
Projected expenditures for clinical programs 43,900,000      
Albumin-Binding Cancer Drugs [Member]        
Estimated Projected Expenditure Type [Line Items]        
Projected expenditures for clinical programs 2,000,000      
General Operation [Member]        
Estimated Projected Expenditure Type [Line Items]        
Projected expenditures for clinical programs 3,800,000      
Other General and Administrative Expenses [Member]        
Estimated Projected Expenditure Type [Line Items]        
Projected expenditures for clinical programs $ 8,900,000