The table below describes the fees and expenses that you pay if you buy and hold shares of the Fund (“Shares”). Investors may pay brokerage commissions on their purchases and sales of Shares.

Shareholder Fees Caption [Text]

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Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

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Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

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2015-09-30

Portfolio Turnover [Heading]

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Portfolio Turnover

Portfolio Turnover [Text Block]

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The Fund pays transaction costs, such as commissions, when it purchases and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may result in higher transaction costs and higher taxes when Shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, may affect the Fund’s performance. This Fund is newly offered. Therefore, it does not have a turnover rate to report for the most recent fiscal year.

Expense Exchange Traded Fund Commissions [Text]

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This example does not take into account brokerage commissions that you pay when purchasing or selling Shares.

Other Expenses, New Fund, Based on Estimates [Text]

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“Other Expenses” are based on estimated amounts for the current fiscal year.

Expense Example [Heading]

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Example

Expense Example Narrative [Text Block]

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This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds. This example does not take into account brokerage commissions that you pay when purchasing or selling Shares.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your Shares at the end of those periods. The example also assumes that your investment has a 5% annual return and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Strategy [Heading]

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Principal Investment Strategies

Strategy Narrative [Text Block]

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The Fund is an actively-managed exchange-traded fund (“ETF”) that will invest under normal circumstances primarily (at least 80% of its assets) in domestic and foreign equity securities of companies that are relevant to the Fund’s investment theme of industrial innovation.

Companies that are expected to focus on and benefit from the development of new products or services, technological improvements and advancements in scientific research related to, among other things, disruptive innovation in energy (“energy transformation companies”), automation and manufacturing (“automation transformation companies” ) , materials, and transportation.

The Adviser considers a company to be an energy transformation company if it seeks to capitalize on innovations or evolutions in: (i) ways that energy is stored or used; (ii) the discovery, collection and/or implementation of new sources of energy, including unconventional sources of oil or natural gas and/or (iii) the production or development of new materials for use in commercial applications of energy production, use or storage.

The Adviser considers a company to be an automation transformation company if it is focused on man capitalizing on the productivity of machines, such as through the automation of functions, processes or activities previously performed by human labor or the use of robotics to perform other functions, activities or processes.

In selecting companies that the Adviser believes are relevant to a particular investment theme, it seeks to identify, using its own internal research and analysis, companies capitalizing on disruptive innovation or that are enabling the further development of a theme in the markets in which they operate. The Adviser’s internal research and analysis leverages insights from diverse sources, including external research, to develop and refine its investment themes and identify and take advantage of trends that have ramifications for individual companies or entire industries. The Adviser will use both “top down” (macro-economic and business cycle analysis) and “bottom up” (valuation, fundamental and quantitative measures) approaches to select investments for the Fund.

Under normal circumstances, substantially all of the Fund’s assets will be invested in equity securities, including common stocks, partnership interests, business trust shares and other equity investments or ownership interests in business enterprises. The Fund’s investments will include issuers of micro-, small-, medium- and large-capitalizations. The Fund’s investments in foreign equity securities will be in both developed and emerging markets. The Fund currently intends to use only ADRs when purchasing foreign securities.

The Fund will be concentrated in issuers in groups of industries in the industrials and information technology sectors, although it will not concentrate in any specific industry.

Strategy Portfolio Concentration [Text]

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The Fund will be concentrated in issuers in groups of industries in the industrials and information technology sectors, although it will not concentrate in any specific industry.

Risk [Heading]

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Principal Risks

Risk Narrative [Text Block]

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There is no assurance that the Fund will meet its investment objective. The value of your investment in the Fund, as well as the amount of return you receive on your investment in the Fund, may fluctuate significantly. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. Therefore, you should consider carefully the following risks before investing in the Fund.

Emerging Market Securities Risk . Investment in securities of emerging market issuers may present risks that are greater than or different from those associated with foreign securities due to less developed and liquid markets and such factors as increased economic, political, regulatory, or other uncertainties.

Equity Securities Risk. The value of the equity securities the Fund holds may fall due to general market and economic conditions, perceptions regarding the industries in which the issuers of securities the Fund holds participate or factors relating to specific companies in which the Fund invests. Equity securities may also be particularly sensitive to general movements in the stock market, and a decline in the broader market may affect the value of the Fund’s equity investments.

Foreign Securities Risk. Investments in the securities of foreign issuers involve risks beyond those associated with investments in U.S. securities. These additional risks include greater market volatility, the availability of less reliable financial information, higher transactional costs, potentially higher custody costs, taxation by foreign governments, decreased market liquidity and political and economic instability. Because the Fund investments in foreign securities currently are made through the purchase of ADRs, the Fund normally will not be hedging any foreign currency exposure (since ADRs are denominated and pay dividends in US dollars).

Industrials Sector Risk. The industrials sector includes companies engaged in the aerospace and defense industry, electrical engineering, machinery, and professional services. Companies in the industrials sector may be adversely affected by changes in government regulation, world events and economic conditions. In addition, companies in the industrials sector may be adversely affected by environmental damages, product liability claims and exchange rates.

Aerospace and Defense Company Risk. Companies in the aerospace and defense industry rely to a large extent on U.S. (and other) Government demand for their products and services and may be significantly affected by changes in government regulations and spending, as well as economic conditions and industry consolidation.

Professional Services Company Risk. Professional services companies may be materially impacted by economic conditions and related fluctuations in client demand for marketing, business, technology and other consulting services. Professional services companies’ success depends in large part upon attracting and retaining key employees and a failure to do so could adversely affect a company’s business. There are relatively few barriers to entry into the professional services market, and new competitors could readily seek to compete in one or more market segments, which could adversely affect company’s operating results through pricing pressure and loss of market share.

Information Technology Sector Risk. The information technology sector includes companies engaged in internet software and services, technology hardware and storage peripherals, electronic equipment instruments and components, and semiconductors and semiconductor equipment. Information technology companies face intense competition, both domestically and internationally, which may have an adverse affect on profit margins. Information technology companies may have limited product lines, markets, financial resources or personnel. The products of information technology companies may face product rapid obsolescence due to technological developments and frequent new product introduction, unpredictable changes in growth rates and competition for the services of qualified personnel. Failure to introduce new products, develop and maintain a loyal customer base or achieve general market acceptance for their products could have a material adverse effect on a company’s business. Companies in the information technology sector are heavily dependent on intellectual property and the loss of patent, copyright and trademark protections may adversely affect the profitability of these companies.

Internet Company Risk. Many Internet-related companies have incurred large losses since their inception and may continue to incur large losses in the hope of capturing market share and generating future revenues. Accordingly, many such companies expect to incur significant operating losses for the foreseeable future, and may never be profitable. The markets in which many Internet companies compete face rapidly evolving industry standards, frequent new service and product announcements, introductions and enhancements and changing customer demands. The failure of an Internet company to adapt to such changes could have a material adverse effect on the company’s business. In addition, the widespread adoption of new Internet, networking, telecommunications technologies, or other technological changes could require substantial expenditures by an Internet company to modify or adapt its services or infrastructure, which could have a material adverse effect on an Internet company’s business.

Semiconductor Company Risk. Competitive pressures may have a significant effect on the financial condition of semi-conductor companies and, as product cycles shorten and manufacturing capacity increases, these companies may become increasingly subject to aggressive pricing, which hampers profitability. Reduced demand for end-user products, under-utilization of manufacturing capacity, and other factors could adversely impact the operating results of companies in the semiconductor sector. Semiconductor companies typically face high capital costs and may be heavily dependent on intellectual property rights. The semiconductor sector is highly cyclical, which may cause the operating results of many semiconductor companies to vary significantly. The stock prices of companies in the semiconductor sector have been and likely will continue to be extremely volatile.

Issuer Risk. Because a Fund may invest in approximately 40 to 50 issuers, it is subject to the risk that the value of the Fund’s portfolio may decline due to a decline in value of the equity securities of particular issuers. The value of an issuer’s equity securities may decline for reasons directly related to the issuer, such as management performance and reduced demand for the issuer’s goods or services.

Large-Capitalization Companies Risk. Large-capitalization companies tend to be less volatile than companies with smaller market capitalizations. In exchange for this potentially lower risk, the value of a large-capitalization company may not rise as much as that of a company with a smaller market capitalization.

Management Risk. As an actively-managed ETF, the Fund is subject to management risk. Although the portfolio manager has significant investment management experience, the Adviser is newly-formed and has no prior experience managing actively-managed ETFs. The ability of the Adviser to successfully implement the Fund’s investment strategies will significantly influence the Fund’s performance.

Market Risk . The value of the Fund’s assets will fluctuate as the markets in which the Fund invests fluctuate. The value of the Fund’s investments may decline, sometimes rapidly and unpredictably, because of economic changes or other events that affect the securities markets.

Market Trading Risk. The Fund faces numerous market trading risks, including disruptions to the creation and redemption processes of the Fund, losses from trading in secondary markets, the existence of extreme market volatility or potential lack of an active trading market for Shares, which may result in Shares trading at a significant premium or discount to their net asset value (“NAV”). If a shareholder purchases Shares at a time when the market price is at a premium to the NAV or sells Shares at a time when the market price is at a discount to the NAV, the shareholder may sustain losses.

Micro-Capitalization Companies Risk. Micro-capitalization companies are subject to substantially greater risks of loss and price fluctuations because their earnings and revenues tend to be less predictable (and some companies may be experiencing significant losses). Their share prices tend to be more volatile and their markets less liquid than companies with larger market capitalizations. The shares of micro-capitalization companies tend to trade less frequently than those of larger, more established companies, which can adversely affect the pricing of these securities and the future ability to sell these securities.

New Fund Risk. There can be no assurance that the Fund will grow to or maintain an economically viable size. The Fund may liquidate and terminate at any time without shareholder approval.

Non-Diversified Risk. The Fund is classified as a “non-diversified” investment company under the Investment Company Act of 1940, as amended (“1940 Act”). Therefore, the Fund may invest a relatively higher percentage of its assets in a relatively smaller number of issuers or may invest a larger proportion of its assets in a single issuer. As a result, the gains and losses on a single investment may have a greater impact on the Fund’s NAV and may make the Fund more volatile than more diversified funds.

Small- and Medium-Capitalization Companies Risk . Small- and medium-capitalization companies may be more volatile and more likely than large-capitalization companies to have narrower product lines, fewer financial resources, less management depth and experience and less competitive strength. Returns on investments in securities of small- and medium-capitalization companies could trail the returns on investments in securities of large-capitalization companies.

Risk Lose Money [Text]

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You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments.

Risk Nondiversified Status [Text]

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The Fund is classified as a “non-diversified” investment company under the Investment Company Act of 1940, as amended (“1940 Act”). Therefore, the Fund may invest a relatively higher percentage of its assets in a relatively smaller number of issuers or may invest a larger proportion of its assets in a single issuer. As a result, the gains and losses on a single investment may have a greater impact on the Fund’s NAV and may make the Fund more volatile than more diversified funds.

Bar Chart and Performance Table [Heading]

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Performance

Performance One Year or Less [Text]

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The Fund has not yet commenced operations and therefore does not have a performance history. Once available, the Fund’s performance information will be accessible on the Fund’s website at http://ark-invest.com.

Performance Availability Website Address [Text]

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http://ark-invest.com

Performance Narrative [Text Block]

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ARK Industrial Innovation ETF (Prospectus Summary) | ARK Industrial Innovation ETF | ARK Industrial Innovation ETF

Risk/Return:

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Shareholder Fees (fees paid directly from your investment)

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None

Management Fee

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0.95%

Distribution and Service (12b-1) Fees

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none

Other Expenses

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0.50%

^[1]

Total Annual Fund Operating Expenses

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1.45%

Expense Reduction

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0.50%

^[2]

Net Annual Fund Operating Expenses

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0.95%

Expense Example, with Redemption, 1 Year

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$ 97

Expense Example, with Redemption, 3 Years

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$ 409

[1]

The Fund bears other expenses that are not covered under the management fee, which may vary and affect the total level of expenses paid by the Fund, such as taxes and governmental fees, brokerage fees, commissions and other transaction expenses, certain custodial fees and expenses, costs of borrowing money, including interest expenses, and extraordinary expenses (such as litigation and indemnification expenses) (“Fund Expenses”). “Other Expenses” are based on estimated amounts for the current fiscal year.

[2]

ARK Investment Management LLC (“Adviser”) has contractually agreed, until September 30, 2015, to waive or limit its management fee or reimburse the Fund to the extent that various organizational and other expenses of the Fund (excluding Fund Expenses detailed in footnote (a) above) exceed 0.95% (“Expense Limit”) of the Fund’s average net assets. Under the Expense Limitation Agreement, which, after the initial term, renews annually for a full year unless terminated by the Adviser upon at least 30 days’ notice prior to the end of the contract term, the Adviser may recoup these waivers and reimbursements in future periods, not exceeding three years, provided organizational and other Fund expenses plus such recoupment, do not exceed the Expense Limit.