Commitments and Contingencies Schedules of Unfunded Commitments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)
Healthcare Royalty Partners | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 7,571	[1]
Healthcare Royalty Partners | Commitment to Invest
Other Commitments [Line Items]
Commitments term	4 years
Eclipse Ventures Fund I, L.P. | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 59
Eclipse Ventures Fund I, L.P. | Commitment to Invest
Other Commitments [Line Items]
Commitments term	4 years
Eclipse Fund II, L.P. | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 100
Eclipse Fund II, L.P. | Commitment to Invest
Other Commitments [Line Items]
Commitments term	5 years
Eclipse Continuity Fund I, L.P. | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 58
Eclipse Continuity Fund I, L.P. | Commitment to Invest
Other Commitments [Line Items]
Commitments term	6 years
Cowen Healthcare Investments II LP | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 1,202
Cowen Healthcare Investments II LP | Commitment to Invest
Other Commitments [Line Items]
Commitments term	1 year
Cowen Healthcare Investments III LP | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 5,094
Cowen Healthcare Investments III LP | Commitment to Invest
Other Commitments [Line Items]
Commitments term	6 years
Cowen Sustainable Investments I LP | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 10,639
Cowen Sustainable Investments I LP | Commitment to Invest
Other Commitments [Line Items]
Commitments term	9 years

[1] The Company is a limited partner of the HealthCare Royalty Partners funds (which are managed by Healthcare Royalty Management) and is a member of HealthCare Royalty Partners General Partners. The Company will make its pro-rata investment in the HealthCare Royalty Partners funds along with the other limited partners.