Revenue recognition - Collaboration and Royalty Revenue (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) payment	Dec. 31, 2019 USD ($)	Aug. 31, 2021 USD ($)	Mar. 31, 2021 USD ($)	Oct. 31, 2020 USD ($)	Aug. 31, 2020 USD ($)	Nov. 30, 2019 USD ($)	Nov. 30, 2011 USD ($)
Collaboration and royalty revenue
Remaining potential milestones that can be achieved	$ 300,000	$ 300,000
Revenue		538,593	$ 380,766	$ 306,980
Collaboration revenue
Collaboration and royalty revenue
Revenue		55,046	42,579	15,674
Royalty revenue
Collaboration and royalty revenue
Revenue		54,643	4,786
SMA License Agreement \| Collaboration revenue
Collaboration and royalty revenue
Revenue		55,000	42,600	15,200
SMA License Agreement \| Royalty revenue
Collaboration and royalty revenue
Revenue		54,600	$ 4,800	$ 0
Research and Development and Sales Milestones \| Collaboration revenue
Collaboration and royalty revenue
Number of milestone payments. \| payment			3
Research And Development Event Milestones \| SMA License Agreement
Collaboration and royalty revenue
Remaining potential milestones that can be achieved	0	0
Milestone payments received					$ 10,000	$ 20,000	$ 7,500		$ 15,000
Research And Development Event Milestones, Period Payment 1 \| SMA License Agreement
Collaboration and royalty revenue
Milestone payments received								$ 20,000
Research And Development Event Milestones, Period Payment 2 \| SMA License Agreement
Collaboration and royalty revenue
Milestone payments received								$ 15,000
Sales Milestones \| SMA License Agreement
Collaboration and royalty revenue
Remaining potential milestones that can be achieved	300,000	300,000
Net sales milestone threshold achieved		$ 500,000
Sales Milestones \| SMA License Agreement \| Prepaids and other current assets
Collaboration and royalty revenue
Milestone payments due	$ 25,000
Maximum \| Research And Development Event Milestones \| SMA License Agreement \| Roche
Collaboration and royalty revenue
Remaining potential milestones that can be achieved										$ 135,000
Maximum \| Sales Milestones \| SMA License Agreement \| Roche
Collaboration and royalty revenue
Remaining potential milestones that can be achieved										$ 325,000