Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

Document and Entity Information - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2022
Feb. 09, 2023
Jun. 30, 2022
Document Information [Line Items]      
Document Type 10-K    
Document Annual Report true    
Amendment Flag false    
Document Period End Date Dec. 31, 2022    
Document Fiscal Year Focus 2022    
Document Fiscal Period Focus FY    
Entity Registrant Name HERCULES CAPITAL, INC.    
Entity Central Index Key 0001280784    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Public Float     $ 1,680
Entity Common Stock, Shares Outstanding   136,480,361  
Entity Current Reporting Status Yes    
Entity Shell Company false    
Entity File Number 814-00702    
Entity Tax Identification Number 74-3113410    
Entity Address, Address Line One 400 Hamilton Avenue    
Entity Address, Address Line Two Suite 310    
Entity Address, City or Town Palo Alto    
Entity Address, State or Province CA    
Entity Address, Postal Zip Code 94301    
City Area Code 650    
Local Phone Number 289-3060    
Entity Interactive Data Current Yes    
Entity Incorporation, State or Country Code MD    
Document Transition Report false    
ICFR Auditor Attestation Flag true    
Documents Incorporated By Reference

Portions of the registrant’s Proxy Statement for its 2023 Annual Meeting of Stockholders to be filed within 120 days after the close of the registrant’s year end are incorporated by reference into Part III of this Annual Report on Form 10-K.

Auditor Firm ID 238    
Auditor Name PricewaterhouseCoopers, LLP    
Auditor Location San Francisco, CA    
Common Stock Par Value $0.001 Per Share      
Document Information [Line Items]      
Title of 12(b) Security Common Shares, par value $0.001 per share    
Trading Symbol HTGC    
Security Exchange Name NYSE    
6.25% Notes Due 2033      
Document Information [Line Items]      
Title of 12(b) Security 6.25% Notes due 2033    
Trading Symbol HCXY    
Security Exchange Name NYSE