Note 10 - Concentrations of Credit Risk	12 Months Ended
Dec. 31, 2022
Notes to Financial Statements
Concentration Risk Disclosure [Text Block]	Note *10.* Concentrations of credit risk The Company’s debt investments consist primarily of loans to development-stage companies at various stages of development in the technology, life science, healthcare information and services and sustainability industries. Many of these companies may have relatively limited operating histories and also may experience variation in operating results. Many of these companies conduct business in regulated industries and could be affected by changes in government regulations. Most of the Company’s borrowers will need additional capital to satisfy their continuing working capital needs and other requirements, and in many instances, to service the interest and principal payments on the loans. The Company’s largest debt investments may vary from year to year as new debt investments are recorded and existing debt investments are repaid. The Company’s five largest debt investments, at cost and fair value, represented 23% and 26% of total debt investments outstanding as of December 31, 2022 and 2021, respectively. No single debt investment represented more than 10% of the total debt investments at cost or fair value as of December 31, 2022 or 2021. Investment income, consisting of interest and fees, can fluctuate significantly upon repayment of large debt investments. Interest income from the five largest debt investments accounted for 15%, 17% and 23% of total interest and fee income on investments for the years ended December 31, 2022, 2021 and 2020, respectively.

Note 10 - Concentrations of Credit Risk

12 Months Ended

Dec. 31, 2022

Concentration Risk Disclosure [Text Block]

Note 10. Concentrations of credit risk

The Company’s debt investments consist primarily of loans to development-stage companies at various stages of development in the technology, life science, healthcare information and services and sustainability industries. Many of these companies may have relatively limited operating histories and also may experience variation in operating results. Many of these companies conduct business in regulated industries and could be affected by changes in government regulations. Most of the Company’s borrowers will need additional capital to satisfy their continuing working capital needs and other requirements, and in many instances, to service the interest and principal payments on the loans.

The Company’s largest debt investments may vary from year to year as new debt investments are recorded and existing debt investments are repaid. The Company’s five largest debt investments, at cost and fair value, represented 23% and 26% of total debt investments outstanding as of December 31, 2022 and 2021, respectively. No single debt investment represented more than 10% of the total debt investments at cost or fair value as of December 31, 2022 or 2021. Investment income, consisting of interest and fees, can fluctuate significantly upon repayment of large debt investments. Interest income from the five largest debt investments accounted for 15%, 17% and 23% of total interest and fee income on investments for the years ended December 31, 2022, 2021 and 2020, respectively.