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Debt - Schedule of Convertible Senior Notes (Detail) - USD ($) | 3 Months Ended | 9 Months Ended |  |  |
--- | --- | --- | --- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019 | May 19, 2020 | May 15, 2020 | Dec. 31, 2019
Debt Instrument [Line Items] |  |  |  |  |  |  |
Interest Expense | $ 39,470,000 | $ 26,502,000 | $ 114,652,000 | $ 61,865,000 |  |  |
Convertible Debt |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Aggregate Principal Amount | 2,384,664,000 |  | 2,384,664,000 |  |  |  |
Unamortized Debt Discount and Debt Issuance Costs | 539,070,000 |  | 539,070,000 |  |  |  | $ 463,348,000
Fair Value | 4,829,067,000 |  | 4,829,067,000 |  |  |  | 2,304,376,000
Contractual Coupon Interest | 9,652,000 | 4,464,000 | 24,646,000 | 12,000,000 |  |  |
Accretion of bond discount | 26,252,000 | 11,143,000 | 71,404,000 | 27,288,000 |  |  |
Amortization of Debt Issuance Costs | 1,416,000 | 926,000 | 4,010,000 | 2,563,000 |  |  |
Interest Expense | 37,320,000 | 16,533,000 | 100,060,000 | 41,851,000 |  |  |
Convertible Debt | 1.375% convertible senior notes due 2026 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Aggregate Principal Amount | $ 500,000,000 |  | $ 500,000,000 |  |  |  |
Stated Interest Rate | 1.375% |  | 1.375% |  |  |  |
Effective Interest Rate | 8.10% |  | 8.10% |  |  |  |
Unamortized Debt Discount and Debt Issuance Costs | $ 157,684,000 |  | $ 157,684,000 |  |  |  | 172,813,000
Fair Value | 1,190,750,000 |  | 1,190,750,000 |  |  |  | 597,380,000
Contractual Coupon Interest | 1,719,000 | 420,000 | 5,157,000 | 420,000 |  |  |
Accretion of bond discount | 5,022,000 | 1,142,000 | 14,768,000 | 1,142,000 |  |  |
Amortization of Debt Issuance Costs | 123,000 | 28,000 | 361,000 | 28,000 |  |  |
Interest Expense | 6,864,000 | 1,590,000 | 20,286,000 | 1,590,000 |  |  |
Convertible Debt | 2.75% convertible senior notes due 2025 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Aggregate Principal Amount | $ 565,000,000 |  | $ 565,000,000 |  | $ 65,000,000.0 | $ 500,000,000.0 |
Stated Interest Rate | 2.75% |  | 2.75% |  | 2.75% | 2.75% |
Effective Interest Rate | 10.32% |  | 10.32% |  |  |  |
Unamortized Debt Discount and Debt Issuance Costs | $ 156,677,000 |  | $ 156,677,000 |  |  | $ 3,300,000 | 0
Fair Value | 978,863,000 |  | 978,863,000 |  |  |  | 0
Contractual Coupon Interest | 3,884,000 | 0 | 5,891,000 | 0 |  |  |
Accretion of bond discount | 6,205,000 | 0 | 9,353,000 | 0 |  |  |
Amortization of Debt Issuance Costs | 331,000 | 0 | 499,000 | 0 |  |  |
Interest Expense | 10,420,000 | 0 | 15,743,000 | 0 |  |  |
Convertible Debt | 0.75% convertible senior notes due 2024 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Aggregate Principal Amount | $ 673,000,000 |  | $ 673,000,000 |  |  |  |
Stated Interest Rate | 0.75% |  | 0.75% |  |  |  |
Effective Interest Rate | 7.68% |  | 7.68% |  |  |  |
Unamortized Debt Discount and Debt Issuance Costs | $ 157,427,000 |  | $ 157,427,000 |  |  |  | 182,462,000
Fair Value | 1,597,480,000 |  | 1,597,480,000 |  |  |  | 819,378,000
Contractual Coupon Interest | 1,262,000 | 275,000 | 3,772,000 | 275,000 |  |  |
Accretion of bond discount | 8,251,000 | 1,681,000 | 24,207,000 | 1,681,000 |  |  |
Amortization of Debt Issuance Costs | 283,000 | 57,000 | 828,000 | 57,000 |  |  |
Interest Expense | 9,796,000 | 2,013,000 | 28,807,000 | 2,013,000 |  |  |
Convertible Debt | 1.50% convertible senior notes due 2023 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Aggregate Principal Amount | $ 373,750,000 |  | $ 373,750,000 |  |  |  |
Stated Interest Rate | 1.50% |  | 1.50% |  |  |  |
Effective Interest Rate | 6.99% |  | 6.99% |  |  |  |
Unamortized Debt Discount and Debt Issuance Costs | $ 51,215,000 |  | $ 51,215,000 |  |  |  | 63,575,000
Fair Value | 535,771,000 |  | 535,771,000 |  |  |  | 356,464,000
Contractual Coupon Interest | 1,402,000 | 1,402,000 | 4,206,000 | 4,206,000 |  |  |
Accretion of bond discount | 3,814,000 | 3,557,000 | 11,260,000 | 10,441,000 |  |  |
Amortization of Debt Issuance Costs | 373,000 | 348,000 | 1,100,000 | 1,026,000 |  |  |
Interest Expense | 5,589,000 | 5,307,000 | 16,566,000 | 15,673,000 |  |  |
Convertible Debt | 2.00% convertible senior notes due 2021 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Aggregate Principal Amount | $ 265,330,000 |  | $ 265,330,000 |  |  |  |
Stated Interest Rate | 2.00% |  | 2.00% |  |  |  |
Effective Interest Rate | 7.43% |  | 7.43% |  |  |  |
Unamortized Debt Discount and Debt Issuance Costs | $ 16,067,000 |  | $ 16,067,000 |  |  |  | 44,498,000
Fair Value | 512,949,000 |  | 512,949,000 |  |  |  | 514,312,000
Contractual Coupon Interest | 1,326,000 | 2,300,000 | 5,429,000 | 6,900,000 |  |  |
Accretion of bond discount | 2,960,000 | 4,763,000 | 11,816,000 | 14,024,000 |  |  |
Amortization of Debt Issuance Costs | 306,000 | 493,000 | 1,222,000 | 1,452,000 |  |  |
Interest Expense | 4,592,000 | 7,556,000 | 18,467,000 | 22,376,000 |  |  |
Convertible Debt | 2.75% convertible senior notes due 2020 |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |
Aggregate Principal Amount | $ 7,584,000 |  | $ 7,584,000 |  |  |  |
Stated Interest Rate | 2.75% |  | 2.75% |  |  |  |
Unamortized Debt Discount and Debt Issuance Costs | $ 0 |  | $ 0 |  |  |  | 0
Fair Value | 13,254,000 |  | 13,254,000 |  |  |  | $ 16,842,000
Contractual Coupon Interest | 59,000 | 67,000 | 191,000 | 199,000 |  |  |
Accretion of bond discount | 0 | 0 | 0 | 0 |  |  |
Amortization of Debt Issuance Costs | 0 | 0 | 0 | 0 |  |  |
Interest Expense | $ 59,000 | $ 67,000 | $ 191,000 | $ 199,000 |  |  |

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