Credit Facilities (Deerfield Warrants Narrative) (Details) - USD ($)			12 Months Ended
	Aug. 09, 2018	Apr. 03, 2017	Dec. 31, 2019	Dec. 31, 2018
2017 Warrants
Line of Credit Facility [Line Items]
Class of warrant or right, exercise limitation threshold		4.985%
Fair value of warrants issued in connection with the facility agreement			$ 2,100,000.0	$ 2,700,000.0
2018 Deerfield Warrants
Line of Credit Facility [Line Items]
Class of warrant or right, expiration date	7 years
Facility Agreement, Due 2023 | Facility Agreement, Due 2023, Deerfield Warrants
Line of Credit Facility [Line Items]
Class of warrant or right, expiration date		7 years