Credit Facilities (Deerfield Warrants Narrative) (Details)	3 Months Ended
	Mar. 31, 2020 USD ($) $ / shares
2017 Deerfield Warrants
Line of Credit Facility [Line Items]
Fair value of warrants issued in connection with the Facility Agreement | $	$ 500,000.0
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
Class of warrant or right, exercise limitation threshold	4.985%
Second Amendment Exercise price
Line of Credit Facility [Line Items]
Exercise price (usd per share)	$ 6.61
Second Amendment Exercise price | 2017 Deerfield Warrants
Line of Credit Facility [Line Items]
Exercise price (usd per share)	6.61
Second Amendment Exercise price | 2018 Deerfield Warrants
Line of Credit Facility [Line Items]
Exercise price (usd per share)	6.61
Upon Satisfaction of Initial Note Exchange Condition
Line of Credit Facility [Line Items]
Exercise price (usd per share)	$ 1.50