Shareholder Report, Average Annual Return (Details) 74200010800_Franklin Biotechnology Discovery Fund_Class C_TSR Annual {Class C} |
12 Months Ended | 60 Months Ended | 120 Months Ended |
|---|---|---|---|
Apr. 30, 2026 |
Apr. 30, 2026 |
Apr. 30, 2026 |
|
| Class C | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Class C | ||
| Average Annual Return, Percent | 63.82% | 7.35% | 9.28% |
| Russell 3000 Index [Member] | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Russell 3000 Index | ||
| Average Annual Return, Percent | 31.01% | 11.91% | 14.76% |
| NASDAQ Biotechnology Index [Member] | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | NASDAQ Biotechnology Index | ||
| Average Annual Return, Percent | 37.61% | 3.80% | 7.65% |
| S&P 500 Index [Member] | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | S&P 500 Index | ||
| Average Annual Return, Percent | 31.05% | 13.14% | 15.26% |