Anti Takeover Provisions Risk [Member] This member stands for Anti-Takeover Provisions Risk. Biotechnology Industry Risk [Member] This member stands for Biotechnology Industry Risk. Concentration In Healthcare Industries [Member] This member stands for Concentration in the Healthcare Industries. Concentration in the Healthcare Industries [Member] Convertible Securities Risk [Member] This member stands for Convertible Securities Risk. This member stands for Counterparty Risk. Counterparty Risk [Member] Credit Default Risk [Member] This member stands for Credit/Default Risk. This member stands for Derivatives Risk. Derivatives Risk [Member] Effects Of Leverage Risk [Member] Effects Of Leverage Risk [Member] Equity-linked Notes [Member] This member stands for Equity-Linked Notes. Equity Linked Notes [Member] This member stands for Equity Securities Risk. Equity Securities Risk [Member] Example Assumes Transaction Fee Of As Percentage Of Offering Price [Member] Example assumes transaction fee of percentage of offering price [Member] It represents as a example assumes transaction fee of as percentage of offering price. Example Does Not Include Sales Load [Member] Example does not include the sales load [Member] It represents as a example does not include the sales load. This member stands for ETFs Risk. Exchange Traded Funds Risk [Member] ETFs Risk [Member] Failure Of Futures Commission Merchants And Clearing Organizations [Member] Represents information of failure of futures commission merchants and clearing organizations. Fee For Open Market Purchase Of Common Shares [Member] Represents the fee for open market purchase of common shares member. Fee for open market purchase of common shares [Member] Fee For Optional Shares Purchase [Member] Represents the fee for optional shares purchases member. Fee for optional shares purchases [Member] Foreign Securities Risk [Member] This member stands for Foreign Securities Risk. This member stands for Forward Contract Risk. Forward Contract Risk [Member] Government Intervention [Member] This member stands for Government Intervention. Healthcare Distributors Sector Risk [Member] This member stands for Healthcare Distributors Sector Risk. Healthcare Equipment Sector Risk [Member] This member stands for Healthcare Equipment Sector Risk. Healthcare Facilities Sector Risk [Member] This member stands for Healthcare Facilities Sector Risk. This member stands for Healthcare Services Sector Risk. Healthcare Services Sector Risk [Member] This member stands for Healthcare Supplies Sector Risk. Healthcare Supplies Sector Risk [Member] This member stands for Healthcare Technology Sector Risk. Healthcare Technology Sector Risk [Member] Interest Rates Risk [Member] Interest Rates Risk [Member] Interest Rate Risk [Member] This member stands for Key Personnel Risk. Key Personnel Risk [Member] This member stands for Leverage Risk. Leverage Risk [Member] This member stands for Life Science and Tools Industry Risk. Life Science And Tools Industry Risk [Member] This member stands for Liquidity Risk. Liquidity Risk [Member] Loan Facility 2016 [Member] Loan Facility 2016 [Member] Loan Facility 2017 [Member] Loan Facility 2017 [Member] Loan Facility 2018 [Member] Loan Facility 2018 [Member] Loan Facility 2019 [Member] Loan Facility 2019 [Member] Loan Facility 2020 [Member] Loan Facility 2020 [Member] Loan Facility 2021 [Member] Loan Facility 2021 [Member] Loan Facility 2022 [Member] Loan Facility 2022 [Member] Loan Facility 2023 [Member] Loan Facility 2023 [Member] Loan Facility 2024 [Member] Loan Facility 2024 [Member]. Loan Facility 2025 [Member] Loan Facility 2025 [Member]. Managed Care Sector Risk [Member] This member stands for Managed Care Sector Risk. Management Risk [Member] Management Risk [Member] Market Disruption And Geopolitical Risk [Member] This member stands for Market Disruption and Geopolitical Risk. Market Events Risk [Member] Market Events Risk [Member] Non Diversification Risk [Member] This member stands for Non-Diversification Risk. This member stands for Non-Investment Grade Securities Risk. Non Investment Grade Securities Risk [Member] This member stands for Pharmaceutical Sector Risk. Pharmaceutical Sector Risk [Member] This member stands for Portfolio Market Risk. Portfolio Market Risk [Member] This member stands for Potential Conflicts of Interest Risk. Potential Conflicts Of Interest Risk [Member] Preferred Shares [Member] Represent the preferred shares member. Private Investment In Public Equity Risk [Member] This member stands for private investments in public equity ("PIPEs") Risk. PIPEs Risk [Member] REIT Risk [Member] Real Estate Investment Trusts Risk [Member] This member stands for Real Estate Investment Trusts Risk. Represents information of regulation as commodity pool. Regulation As Commodity Pool [Member] This member stands for Related Party Transactions Risk. Related Party Transactions Risk [Member] This member stands for Restricted Securities and Valuation Risk. Restricted Securities And Valuation Risk [Member] This member stands for Risks Associated with the Fund's Option Strategy. Risks Associated With Funds Option Strategy [Member] Risks Associated with the Fund's Option Strategy [Member] Risks Associated With Regulatory And Policy Changes [Member] This member stands for Risks Associated with Regulatory and Policy Changes. Sales Of Shares Held In Dividend Reinvestment Accounts [Member] Represents the sales of shares held In dividend reinvestment accounts member. Sales of shares held In dividend reinvestment accounts [Member] This member stands for security market risk-discount to net asset value. Security Market Risk - Discount to NAV [Member] Security Market Risk Discount To Net Asset Value [Member] Selection Risk [Member] This member stands for Selection Risk. This member stands for Special Purpose Acquisition Company Risk. Special Purpose Acquisition Company Risk [Member] This member stands for Venture Capital Investments Risk. Venture Capital Investments Risk [Member] Class of Stock [Domain] Debt Instrument Name [Domain]