Hercules Capital, Inc. Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Investments - Schedule of Fair Value Portfolio by Industry Sector (Details)

Investments - Schedule of Fair Value Portfolio by Industry Sector (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Schedule Of Investments [Line Items]
Investments at Fair Value	$ 3,568,539	$ 3,248,046
Industry Sector Concentration Risk \| Total Industry Sectors
Schedule Of Investments [Line Items]
Investments at Fair Value	3,568,539	3,248,046
Industry Sector Concentration Risk \| Drug Discovery & Development
Schedule Of Investments [Line Items]
Investments at Fair Value	1,244,782	1,257,699
Industry Sector Concentration Risk \| Software
Schedule Of Investments [Line Items]
Investments at Fair Value	948,141	764,985
Industry Sector Concentration Risk \| Consumer & Business Services
Schedule Of Investments [Line Items]
Investments at Fair Value	351,632	525,973
Industry Sector Concentration Risk \| Healthcare Services, Other
Schedule Of Investments [Line Items]
Investments at Fair Value	568,751	300,079
Industry Sector Concentration Risk \| Information Services
Schedule Of Investments [Line Items]
Investments at Fair Value	77,434	126,605
Industry Sector Concentration Risk \| Diversified Financial Services
Schedule Of Investments [Line Items]
Investments at Fair Value	111,312	114,722
Industry Sector Concentration Risk \| Electronics & Computer Hardware
Schedule Of Investments [Line Items]
Investments at Fair Value	76,191	20,324
Industry Sector Concentration Risk \| Medical Devices & Equipment
Schedule Of Investments [Line Items]
Investments at Fair Value	55,653	22,096
Industry Sector Concentration Risk \| Space Technologies
Schedule Of Investments [Line Items]
Investments at Fair Value	45,498	0
Industry Sector Concentration Risk \| Biotechnology Tools
Schedule Of Investments [Line Items]
Investments at Fair Value	35,149	48,381
Industry Sector Concentration Risk \| Communications & Networking
Schedule Of Investments [Line Items]
Investments at Fair Value	29,778	29,400
Industry Sector Concentration Risk \| Sustainable and Renewable Technology
Schedule Of Investments [Line Items]
Investments at Fair Value	20,301	9,581
Industry Sector Concentration Risk \| Media/Content/Info
Schedule Of Investments [Line Items]
Investments at Fair Value	94	12,704
Industry Sector Concentration Risk \| Manufacturing Technology
Schedule Of Investments [Line Items]
Investments at Fair Value	1,680	11,006
Industry Sector Concentration Risk \| Consumer & Business Products
Schedule Of Investments [Line Items]
Investments at Fair Value	1,223	2,589
Industry Sector Concentration Risk \| Semiconductors
Schedule Of Investments [Line Items]
Investments at Fair Value	903	1,205
Industry Sector Concentration Risk \| Surgical Devices
Schedule Of Investments [Line Items]
Investments at Fair Value	0	676
Industry Sector Concentration Risk \| Drug Delivery
Schedule Of Investments [Line Items]
Investments at Fair Value	$ 17	$ 21
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Total Industry Sectors
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	100.00%	100.00%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Drug Discovery & Development
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	34.90%	38.70%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Software
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	26.60%	23.60%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Consumer & Business Services
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	9.90%	16.20%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Healthcare Services, Other
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	15.90%	9.30%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Information Services
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	2.20%	3.90%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Diversified Financial Services
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	3.10%	3.50%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Electronics & Computer Hardware
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	2.10%	0.60%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Medical Devices & Equipment
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	1.60%	0.70%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Space Technologies
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	1.30%	0.00%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Biotechnology Tools
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	1.00%	1.50%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Communications & Networking
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	0.80%	0.90%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Sustainable and Renewable Technology
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	0.60%	0.30%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Media/Content/Info
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	0.00%	0.40%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Manufacturing Technology
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	0.00%	0.30%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Consumer & Business Products
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	0.00%	0.10%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Semiconductors
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	0.00%	0.00%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Surgical Devices
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	0.00%	0.00%
Industry Sector Concentration Risk \| Industry Sub Sector Investments Benchmark \| Drug Delivery
Schedule Of Investments [Line Items]
Percentage of Total Portfolio	0.00%	0.00%