Revenue - Development and Commercialization Agreement (Details) $ in Thousands	1 Months Ended				3 Months Ended			6 Months Ended		12 Months Ended		24 Months Ended
	Dec. 31, 2019 USD ($) plan	Jun. 30, 2019 USD ($)	Feb. 28, 2018	Jan. 31, 2015 plan	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Mar. 31, 2020 USD ($)
Collaborative Arrangements and Co-Promote Agreement
Milestone payment					$ 15,008		$ 26,150	$ 34,870	$ 31,488
Percentage of profit share			33.00%					35.00%
Mylan
Collaborative Arrangements and Co-Promote Agreement
Upfront payment receivable		$ 18,500
Potential milestone or contingent payments													$ 1,500
Transaction price					34,200			$ 34,200
Number of performance obligations | plan				2
Performance period (in years)				17 years				12 years
Deferred revenue					300			$ 300
Percentage of profit share								65.00%
Mylan | Purchase Agreement
Collaborative Arrangements and Co-Promote Agreement
Premium proceeds from sale of ordinary shares											$ 4,200
Mylan | Development and Commercialization Agreement
Collaborative Arrangements and Co-Promote Agreement
Initial cash payment											$ 15,000	$ 30,000
Mylan | YUPELRI Monotherapy
Collaborative Arrangements and Co-Promote Agreement
Potential milestone or contingent payments		9,000					9,000		9,000
Mylan | YUPELRI Monotherapy | Development and Commercialization Agreement
Collaborative Arrangements and Co-Promote Agreement
Potential milestone or contingent payments					160,000			$ 160,000
Mylan | Future potential combination products
Collaborative Arrangements and Co-Promote Agreement
Potential milestone or contingent payments		7,500			45,000		7,500	45,000	7,500
Mylan | Milestone - 50% enrollment in Phase 3 twelve-month safety study | Development and Commercialization Agreement
Collaborative Arrangements and Co-Promote Agreement
Milestone payment										$ 15,000
Mylan | Sales milestones
Collaborative Arrangements and Co-Promote Agreement
Potential milestone or contingent payments		$ 37,500					$ 37,500		$ 37,500
Mylan | Sales milestones | YUPELRI Monotherapy
Collaborative Arrangements and Co-Promote Agreement
Potential milestone or contingent payments					$ 150,000			$ 150,000
Pfizer
Collaborative Arrangements and Co-Promote Agreement
Upfront payment receivable	$ 10,000					$ 10,000
Number of performance obligations | plan	2
Pfizer | Sales milestones
Collaborative Arrangements and Co-Promote Agreement
Milestone payment	$ 240,000