Commitments and Contingencies (Details)	3 Months Ended
	Mar. 31, 2014
Minimum
Patent appeals and market exclusivity
Estimated term to defend the validity of patent through the appeals process	2 years
Ferumoxytol term of data and market exclusivity even if there is no successful outcome from the appeals process	8 years
Maximum
Patent appeals and market exclusivity
Estimated term to defend the validity of patent through the appeals process	3 years
Ferumoxytol term of data and market exclusivity even if there is no successful outcome from the appeals process	10 years