Revenue - Revenue from Collaborative Arrangements (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Collaborative Arrangements and Co-Promote Agreement
Revenue	$ 29,499	$ 12,427	$ 26,150	$ 5,338	$ 15,737	$ 12,838	$ 23,476	$ 8,319	$ 73,414	$ 60,370	$ 15,386
Collaboration revenue recognized in the period from:
Amounts included in deferred revenue at the beginning of the period									31,245	130
Janssen
Collaborative Arrangements and Co-Promote Agreement
Revenue									31,096	31,053
Collaboration revenue recognized in the period from:
Amounts included in deferred revenue at the beginning of the period									37,900
Alfasigma
Collaborative Arrangements and Co-Promote Agreement
Revenue									125	10,678
Other
Collaborative Arrangements and Co-Promote Agreement
Revenue									29	60	598
Collaborative revenue
Collaborative Arrangements and Co-Promote Agreement
Revenue									$ 31,250	$ 41,791	$ 598