Collaboration Agreements And Other Contractual Arrangements (Details) $ in Millions					1 Months Ended	6 Months Ended		12 Months Ended
	Dec. 20, 2017 product	Mar. 01, 2016 USD ($)	May 15, 2015 USD ($) product	May 01, 2015 USD ($) product	Dec. 31, 2017 USD ($)	Dec. 31, 2015 USD ($)	Dec. 27, 2014 USD ($)	Dec. 31, 2021 product	Dec. 31, 2019 product	Dec. 31, 2017 USD ($) product	Dec. 31, 2016 USD ($) product	Jun. 27, 2015 USD ($) product	Dec. 31, 2020 USD ($)	Dec. 31, 2018 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development						$ 88.2	$ 89.8			$ 167.7	$ 184.0	$ 187.8
Royalty Pharma contingent milestone payments		$ 30.0
Business combination, number of products purchased | product										3	2	2
May 2015 agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of products added to agreement | product											3
Business combination, number of products purchased | product			2
May 2015 agreement | Minimum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty Pharma contingent milestone payments			$ 78.0								$ 126.0
May 2015 agreement | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty Pharma contingent milestone payments			$ 105.0								$ 174.0
Development-Stage Rx Products
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development				$ 18.0
Business combination, number of products purchased | product				2
Number of products sold | product	1
Development-Stage Rx Products | Minimum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty payment period		7 years
Development-Stage Rx Products | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty payment period		10 years
Forecast
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty Pharma contingent milestone payments													$ 54.8	$ 79.7
Forecast | May 2015 agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Business combination, number of products purchased | product								2	1
ANDA
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development					$ 2.5
ANDA | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty Pharma contingent milestone payments					$ 14.5					$ 14.5