Consolidated Schedule of Investments - Schedule of Investments (Details) (Parentheticals) - USD ($)	Jun. 30, 2025	Dec. 31, 2024
Investment, percent of net assets	96.80%	100.00%
Investment Owned, Net Assets, Percentage	96.80%	100.00%
Investment, cost	$ 92,313,380	$ 116,682,498
Asset Less Noninvestment Liability, Percent of Net Asset	3.20%	0.00%
Total percentage of net asset value	100.00%	100.00%
Asset Less Noninvestment Liability, Percent of Net Asset	3.20%	0.00%
Total percentage of net asset value	100.00%	100.00%
Equipment Leasing Sector [Member] \| EQX Capital, Inc [Member]
Investment, percent of net assets	3.50%	2.80%
Investment Owned, Net Assets, Percentage	3.50%	2.80%
Semiconductor Equipment Sector [Member] \| Lyncean Technologies, Inc. [Member] \| Series B Preferred Stock [Member]
Investment, percent of net assets	0.00%	0.00%
Investment Owned, Net Assets, Percentage	0.00%	0.00%
Semiconductor Equipment Sector [Member] \| Revasum, Inc [Member] \| Chess Depositary Interests (CDIs) [Member]
Investment, percent of net assets	0.00%	0.00%
Investment Owned, Net Assets, Percentage	0.00%	0.00%
Investment Sector [Member] \| Fidelity Investments [Member]
Investment, percent of net assets	67.60%	70.30%
Investment Owned, Net Assets, Percentage	67.60%	70.30%
Medical Devices Sector [Member] \| IntraOp Medical Corp. [Member]
Investment, percent of net assets	0.60%	2.40%
Investment Owned, Net Assets, Percentage	0.60%	2.40%
Advanced Materials Sector [Member] \| UCT Coatings, Inc. [Member] \| Common Stock [Member]
Investment, percent of net assets	25.10%	24.50%
Investment Owned, Net Assets, Percentage	25.10%	24.50%
Automotive Sector [Member] \| Wrightspeed Inc [Member]
Investment, percent of net assets	0.00%	0.00%
Investment Owned, Net Assets, Percentage	0.00%	0.00%

Firsthand Technology Value Fund, Inc. 10-Q