Commitments and Contingencies Schedules of Unfunded Commitments (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($)
Healthcare Royalty Partners | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 6,093	[1]
Healthcare Royalty Partners | Commitment to Invest
Other Commitments [Line Items]
Commitments term	3 years 3 months 18 days
Eclipse Ventures Fund I, L.P. | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 28
Eclipse Ventures Fund I, L.P. | Commitment to Invest
Other Commitments [Line Items]
Commitments term	3 years 3 months 18 days
Eclipse Fund II, L.P. | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 33
Eclipse Fund II, L.P. | Commitment to Invest
Other Commitments [Line Items]
Commitments term	4 years 3 months 18 days
Eclipse Continuity Fund I, L.P. | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 34
Eclipse Continuity Fund I, L.P. | Commitment to Invest
Other Commitments [Line Items]
Commitments term	5 years 3 months 18 days
Cowen Healthcare Investments III LP | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 3,207
Cowen Healthcare Investments III LP | Commitment to Invest
Other Commitments [Line Items]
Commitments term	5 years 3 months 18 days
Cowen Healthcare Investments IV LP | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 6,868
Cowen Healthcare Investments IV LP | Commitment to Invest
Other Commitments [Line Items]
Commitments term	6 years 3 months 18 days
Cowen Sustainable Investments I LP | Unfunded Commitments
Other Commitments [Line Items]
Other commitments, unfunded amount	$ 15,715
Cowen Sustainable Investments I LP | Commitment to Invest
Other Commitments [Line Items]
Commitments term	8 years 3 months 18 days

[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.