Liquidity and Capital Resources (Details) - USD ($)			6 Months Ended
	Jul. 21, 2015	Feb. 05, 2014	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Estimated projected expenditure [Line Items]
Cash and cash equivalents			$ 38,833,736	$ 32,218,905	$ 51,866,891	$ 11,483,112
Short-term investments			15,002,213	$ 45,621,593
Net proceeds received from underwritten public offering		$ 80,500,000
Currently projected expenditures for clinical programs			54,000,000
Subsequent Event [Member]
Estimated projected expenditure [Line Items]
Net proceeds received from underwritten public offering	$ 26,800,000
Aldoxorubicin [Member]
Estimated projected expenditure [Line Items]
Currently projected expenditures for clinical programs			37,000,000
Other Programs [Member]
Estimated projected expenditure [Line Items]
Currently projected expenditures for clinical programs			2,300,000
General Operation [Member]
Estimated projected expenditure [Line Items]
Currently projected expenditures for clinical programs			3,900,000
Other General and Administrative Expenses [Member]
Estimated projected expenditure [Line Items]
Currently projected expenditures for clinical programs			$ 10,800,000