Collaborative Arrangements and Acquisitions - Parion Sciences, Inc. (Details) - USD ($)		1 Months Ended	3 Months Ended		9 Months Ended		28 Months Ended
	Jun. 04, 2015	Jun. 30, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2015
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative revenues			$ 26,292,000	$ 259,000	$ 286,123,000	$ 1,008,000
(Benefit from) provision for income taxes			(125,903,000)	503,000	(117,581,000)	24,118,000
Business Combination, Consideration Transferred [Abstract]
Intangible assets			29,000,000		29,000,000		$ 29,000,000	$ 284,340,000
Deconsolidation of VIE					7,100,000
Intangible asset impairment charge			255,340,000	0	255,340,000	0
Parion Sciences, Inc.
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative arrangement, up-front payment	$ 80,000,000	$ 80,000,000					85,000,000
Prior to marketing approval, time period of notice required to terminate (in days)		90 days
Subsequent to marketing approval, time period of notice required to terminate (in days)		180 days
Change of control prior to clinical trial, time period of notice required to terminate (in days)		30 days
Term of agreement following first commercial sale (in years)		10 years
(Benefit from) provision for income taxes			(126,200,000)
(Benefit from) provision for income taxes, attributable to intangible asset impairment			(97,700,000)
(Benefit from) provision for income taxes, attributable to decrease in the fair value of contingent consideration liability			(28,500,000)
Business Combination, Consideration Transferred [Abstract]
Intangible assets	255,300,000
Noncontrolling interest, fair value	164,300,000
Deferred tax liabilities, net	91,000,000
Other liabilities / assets, net	$ 10,500,000
Deconsolidation of VIE			7,100,000
Intangible asset impairment charge			255,300,000
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability			(69,600,000)
ENaC Inhibitors in CF | Parion Sciences, Inc.
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative arrangement, development and regulatory potential milestone payments maximum		$ 490,000,000
Collaborative arrangement regulatory potential milestone payments maximum, global filling and approval		360,000,000
Enac Inhibitors in Non Cf | Parion Sciences, Inc.
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative arrangement, development and regulatory potential milestone payments maximum		370,000,000
Additional Enac Inhibitors | Parion Sciences, Inc.
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative arrangement, development and regulatory potential milestone payments maximum		$ 230,000,000
Variable Interest Entity, Primary Beneficiary
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
(Benefit from) provision for income taxes			(120,181,000)	(510,000)	(111,658,000)	20,063,000
Business Combination, Consideration Transferred [Abstract]
Intangible assets			29,000,000		29,000,000		$ 29,000,000	$ 284,340,000
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability			(69,550,000)	1,200,000	(62,560,000)	59,350,000
Variable Interest Entity, Primary Beneficiary | Parion Sciences, Inc.
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative revenues			20,000,000		40,000,000
(Benefit from) provision for income taxes			7,400,000		14,800,000
Business Combination, Consideration Transferred [Abstract]
Intangible assets									$ 255,300,000
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability			$ (69,550,000)	$ 1,100,000	$ (63,460,000)	$ 58,500,000