Share-Based Compensation (Schedule Of Share-Based Compensation Expense Included In Statements Of Operations) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 2,210,238	$ 1,199,334	$ 4,528,232
Research And Development Expenses [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	630,296	235,138	1,076,655
Selling, General And Administrative Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 1,579,942	$ 964,196	$ 3,451,577