Summary of Significant Accounting Policies (Schedule of Concentration Risk) (Details)	12 Months Ended
	Dec. 31, 2018
Net Product Sales
Concentration Risk [Line Items]
Concentration risk	98.00%
As of December 31, 2018
Concentration Risk [Line Items]
Concentration risk	98.00%
Customer A | Net Product Sales
Concentration Risk [Line Items]
Concentration risk	37.00%
Customer A | As of December 31, 2018
Concentration Risk [Line Items]
Concentration risk	44.00%
Customer B | Net Product Sales
Concentration Risk [Line Items]
Concentration risk	31.00%
Customer B | As of December 31, 2018
Concentration Risk [Line Items]
Concentration risk	28.00%
Customer C | Net Product Sales
Concentration Risk [Line Items]
Concentration risk	30.00%
Customer C | As of December 31, 2018
Concentration Risk [Line Items]
Concentration risk	26.00%