Fair value of financial instruments and marketable securities - Hierarchy (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Financial assets and liabilities measured at fair value on recurring basis
Marketable securities - available for sale	$ 154,973	$ 376,685
Contingent consideration payable	163,000	239,900
Recurring basis
Financial assets and liabilities measured at fair value on recurring basis
ClearPoint Equity Investments	16,894	14,525
ClearPoint convertible debt security	22,966	20,971
Recurring basis | Quoted prices in active markets for identical assets (Level 1)
Financial assets and liabilities measured at fair value on recurring basis
ClearPoint Equity Investments	16,894	14,525
Recurring basis | Significant other observable inputs (Level 2)
Financial assets and liabilities measured at fair value on recurring basis
ClearPoint convertible debt security	22,966	20,971
Recurring basis | Development and Regulatory Milestones
Financial assets and liabilities measured at fair value on recurring basis
Contingent consideration payable	78,700	139,300
Recurring basis | Development and Regulatory Milestones | Significant unobservable inputs (Level 3)
Financial assets and liabilities measured at fair value on recurring basis
Contingent consideration payable	78,700	139,300
Recurring basis | Net Sales Milestones and Royalties
Financial assets and liabilities measured at fair value on recurring basis
Contingent consideration payable	84,300	100,600
Recurring basis | Net Sales Milestones and Royalties | Significant unobservable inputs (Level 3)
Financial assets and liabilities measured at fair value on recurring basis
Contingent consideration payable	84,300	100,600
Recurring basis | Marketable securities
Financial assets and liabilities measured at fair value on recurring basis
Marketable securities - available for sale	154,973	376,685
Marketable securities - equity investments	192,414	206,973
Recurring basis | Marketable securities | Quoted prices in active markets for identical assets (Level 1)
Financial assets and liabilities measured at fair value on recurring basis
Marketable securities - equity investments	192,414	206,973
Recurring basis | Marketable securities | Significant other observable inputs (Level 2)
Financial assets and liabilities measured at fair value on recurring basis
Marketable securities - available for sale	$ 154,973	$ 376,685