v3.8.0.1

Significant Accounting Policies (Tables) | 9 Months Ended
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Sep. 30, 2017
Accounting Policies [Abstract] |
Cut-off Times and Times of Calculation of Funds' Final Net Asset Value for Creation and Redemption of Fund Shares | The cut-off times and the times of the calculation of the Funds’ final net asset value for creation and redemption of fund Shares for the nine months ended September 30, 2017 were as follows. All times are Eastern Standard Time:
|  | Create/Redeem Cut-off* |  |  | NAV Calculation Time |  |  | NAV Calculation Date |
UltraShort Silver, Ultra Silver |  |  | 6:30 a.m. |  |  |  | 7:00 a.m. |  |  |  | September 30, 2017 |
UltraShort Gold, Ultra Gold |  |  | 9:30 a.m. |  |  |  | 10:00 a.m. |  |  |  | September 30, 2017 |
UltraShort Bloomberg Crude Oil, Ultra Bloomberg Crude Oil |  |  | 2:00 p.m. |  |  |  | 2:30 p.m. |  |  |  | September 30, 2017 |
UltraPro 3x Short Crude Oil ETF |  |  |  |  |  |  |  |  |  |  |  |
UltraPro 3x Crude Oil ETF |  |  |  |  |  |  |  |  |  |  |  |
UltraShort Bloomberg Natural Gas, Ultra Bloomberg Natural Gas |  |  | 2:00 p.m. |  |  |  | 2:30 p.m. |  |  |  | September 30, 2017 |
UltraShort Australian Dollar |  |  | 3:00 p.m. |  |  |  | 4:00 p.m. |  |  |  | September 30, 2017 |
Short Euro |  |  | 3:00 p.m. |  |  |  | 4:00 p.m. |  |  |  | September 30, 2017 |
UltraShort Euro, Ultra Euro |  |  |  |  |  |  |  |  |  |  |  |
UltraShort Yen, Ultra Yen |  |  | 3:00 p.m. |  |  |  | 4:00 p.m. |  |  |  | September 30, 2017 |
VIX Short-Term Futures ETF, Ultra VIX Short-Term Futures ETF, Short VIX Short-Term Futures ETF |  |  | 2:00 p.m. |  |  |  | 4:15 p.m. |  |  |  | September 30, 2017 |
VIX Mid-Term Futures ETF |  |  | 2:00 p.m. |  |  |  | 4:15 p.m. |  |  |  | September 30, 2017 |
* | Although the Funds’ shares may continue to trade on secondary markets subsequent to the calculation of the final NAV, these times represent the final opportunity to transact in creation or redemption units for the nine months ended September 30, 2017.
Valuation of Investments using Fair Value Hierarchy | The following table summarizes the valuation of investments at September 30, 2017 using the fair value hierarchy:
|  | Level I - Quoted Prices |  |  | Level II - Other Significant Observable Inputs |  |  |  |
|  | Short-Term U.S. Government and Agencies |  |  | Futures Contracts* |  |  | Forward Agreements |  |  | Foreign Currency Forward Contracts |  |  | Swap Agreements |  |  | Total |
VIX Short-Term Futures ETF |  | $ | 186,716,429 |  |  | $ | (18,329,321 | ) |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 168,387,108 |
VIX Mid-Term Futures ETF |  |  | 35,955,278 |  |  |  | (1,941,640 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 34,013,638 |
Short VIX Short-Term Futures ETF |  |  | 770,134,521 |  |  |  | 94,244,035 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 864,378,556 |
Ultra VIX Short-Term Futures ETF |  |  | 521,315,100 |  |  |  | (101,763,031 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 419,552,069 |
UltraShort Bloomberg Crude Oil |  |  | 246,666,306 |  |  |  | (5,367,489 | ) |  |  | — |  |  |  | — |  |  |  | (13,678,377 | ) |  |  | 227,620,440 |
UltraPro 3X Short Crude Oil ETF |  |  | — |  |  |  | (2,423,370 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | (2,423,370 | )
UltraShort Bloomberg Natural Gas |  |  | 2,998,697 |  |  |  | 348,521 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 3,347,218 |
UltraShort Gold |  |  | 34,940,087 |  |  |  | (9,540 | ) |  |  | 2,961,605 |  |  |  | — |  |  |  | — |  |  |  | 37,892,152 |
UltraShort Silver |  |  | 17,966,229 |  |  |  | 4,940 |  |  |  | 2,152,433 |  |  |  | — |  |  |  | — |  |  |  | 20,123,602 |
Short Euro |  |  | 5,998,433 |  |  |  | 106,206 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 6,104,639 |
UltraShort Australian Dollar |  |  | 7,997,911 |  |  |  | 379,490 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 8,377,401 |
UltraShort Euro |  |  | 219,684,550 |  |  |  | — |  |  |  | — |  |  |  | 3,899,693 |  |  |  | — |  |  |  | 223,584,243 |
UltraShort Yen |  |  | 137,818,917 |  |  |  | — |  |  |  | — |  |  |  | 9,246,879 |  |  |  | — |  |  |  | 147,065,796 |
Ultra Bloomberg Crude Oil |  |  | 562,359,737 |  |  |  | 13,817,653 |  |  |  | — |  |  |  | — |  |  |  | 40,796,900 |  |  |  | 616,974,290 |
UltraPro 3X Crude Oil ETF |  |  | — |  |  |  | 1,272,779 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 1,272,779 |
Ultra Bloomberg Natural Gas |  |  | 42,919,932 |  |  |  | (971,690 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 41,948,242 |
Ultra Gold |  |  | 101,900,580 |  |  |  | 9,520 |  |  |  | (8,453,427 | ) |  |  | — |  |  |  | — |  |  |  | 93,456,673 |
Ultra Silver |  |  | 270,629,525 |  |  |  | (4,940 | ) |  |  | (28,243,802 | ) |  |  | — |  |  |  | — |  |  |  | 242,380,783 |
Ultra Euro |  |  | 10,995,765 |  |  |  | — |  |  |  | — |  |  |  | (209,360 | ) |  |  | — |  |  |  | 10,786,405 |
Ultra Yen |  |  | 4,662,411 |  |  |  | — |  |  |  | — |  |  |  | (395,309 | ) |  |  | — |  |  |  | 4,267,102 |
Total Trust |  | $ | 3,181,660,408 |  |  | $ | (20,627,877 | ) |  | $ | (31,583,191 | ) |  | $ | 12,541,903 |  |  | $ | 27,118,523 |  |  | $ | 3,169,109,766 |
* | Includes cumulative appreciation/depreciation of futures contracts as reported in the Schedules of Investments. Only current day’s variation margin is reported within the Statements of Financial Condition in receivable/payable on open futures.
At September 30, 2017, there were no Level III portfolio investments for which significant unobservable inputs were used to determine fair value. The Funds’ policy is to recognize transfers between valuation levels at the end of the reporting period. At September 30, 2017, there were no significant transfers in or out of Level I and Level II fair value measurements. The inputs or methodology used for valuing investments are not necessarily an indication of the risk associated with investing in those securities. The following table summarizes the valuation of investments at December 31, 2016 using the fair value hierarchy:
|  | Level I - Quoted Prices |  |  | Level II - Other Significant Observable Inputs |  |  |  |
|  | Short-Term U.S. Government and Agencies |  |  | Futures Contracts* |  |  | Forward Agreements |  |  | Foreign Currency Forward Contracts |  |  | Swap Agreements |  |  | Total |
VIX Short-Term Futures ETF |  | $ | 147,991,233 |  |  | $ | (468,652 | ) |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | 147,522,581 |
VIX Mid-Term Futures ETF |  |  | 45,486,235 |  |  |  | (1,288,245 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 44,197,990 |
Short VIX Short-Term Futures ETF |  |  | 170,396,436 |  |  |  | (10,309,611 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 160,086,825 |
Ultra VIX Short-Term Futures ETF |  |  | 434,671,795 |  |  |  | (7,972,237 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 426,699,558 |
UltraShort Bloomberg Crude Oil |  |  | 205,694,385 |  |  |  | (1,426,815 | ) |  |  | — |  |  |  | — |  |  |  | (12,206,881 | ) |  |  | 192,060,689 |
UltraShort Bloomberg Natural Gas |  |  | 2,899,151 |  |  |  | (482,031 | ) |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 2,417,120 |
UltraShort Gold |  |  | 60,540,555 |  |  |  | 18,980 |  |  |  | 3,033,566 |  |  |  | — |  |  |  | — |  |  |  | 63,593,101 |
UltraShort Silver |  |  | 21,550,319 |  |  |  | 27,310 |  |  |  | 1,384,246 |  |  |  | — |  |  |  | — |  |  |  | 22,961,875 |
Short Euro |  |  | 13,164,828 |  |  |  | 132,900 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 13,297,728 |
UltraShort Australian Dollar |  |  | 12,909,619 |  |  |  | 1,182,340 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 14,091,959 |
UltraShort Euro |  |  | 337,375,787 |  |  |  | — |  |  |  | — |  |  |  | 16,162,931 |  |  |  | — |  |  |  | 353,538,718 |
UltraShort Yen |  |  | 257,102,313 |  |  |  | — |  |  |  | — |  |  |  | 16,744,937 |  |  |  | — |  |  |  | 273,847,250 |
Ultra Bloomberg Crude Oil |  |  | 885,050,007 |  |  |  | 5,537,165 |  |  |  | — |  |  |  | — |  |  |  | 55,358,571 |  |  |  | 945,945,743 |
Ultra Bloomberg Natural Gas |  |  | 36,183,648 |  |  |  | 2,536,720 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 38,720,368 |
Ultra Gold |  |  | 95,356,621 |  |  |  | (18,960 | ) |  |  | (4,431,107 | ) |  |  | — |  |  |  | — |  |  |  | 90,906,554 |
Ultra Silver |  |  | 295,300,799 |  |  |  | (27,360 | ) |  |  | (20,976,189 | ) |  |  | — |  |  |  | — |  |  |  | 274,297,250 |
Ultra Euro |  |  | 11,891,831 |  |  |  | — |  |  |  | — |  |  |  | (574,010 | ) |  |  | — |  |  |  | 11,317,821 |
Ultra Yen |  |  | 5,282,879 |  |  |  | — |  |  |  | — |  |  |  | (342,076 | ) |  |  | — |  |  |  | 4,940,803 |
Total Trust |  | $ | 3,038,848,441 |  |  | $ | (12,558,496 | ) |  | $ | (20,989,484 | ) |  | $ | 31,991,782 |  |  | $ | 43,151,690 |  |  | $ | 3,080,443,933 |
* | Includes cumulative appreciation/depreciation of futures contracts as reported in the Schedules of Investments. Only current day’s variation margin is reported within the Statements of Financial Condition in receivable/payable on open futures.

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