Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2025	Mar. 01, 2026
Document Information [Line Items]
Entity Central Index Key	0001495584
Entity Registrant Name	Firsthand Technology Value Fund, Inc.
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2025
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2025
Document Transition Report	false
Entity File Number	814-00830
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	27-3008946
Entity Address, Address Line One	150 Almaden Boulevard, Suite 1250
Entity Address, City or Town	San Jose
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95113
City Area Code	408
Local Phone Number	886-7096
Title of 12(b) Security	Common Stock, $0.001 par value
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float	$ 84,000
Entity Common Stock, Shares Outstanding		6,892,540
No Trading Symbol Flag	true
Auditor Name	TAIT, WELLER & BAKER LLP
Auditor Firm ID	445
Auditor Location	Philadelphia, Pennsylvania