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DEBT - Convertible Senior Notes due in 2025 Narrative (Details) |  |  | 1 Months Ended | 3 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Mar. 01, 2021 USD ($) | Mar. 09, 2020 USD ($) trading_day $ / shares shares | Apr. 27, 2021 USD ($) | Mar. 31, 2021 USD ($) $ / shares shares | Mar. 31, 2020 USD ($) | Dec. 31, 2020 USD ($) $ / shares shares | May 20, 2020 USD ($) $ / shares shares | May 19, 2020 shares
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Debt, current |  |  |  | $ 84,356,000 |  | $ 325,967,000 |  |
Common stock, par value (in usd per share) | $ / shares |  |  |  | $ 0.00001 |  | $ 0.00001 | $ 0.00001 |
Common stock, shares authorized (in shares) | shares |  |  |  | 200,000,000 |  | 200,000,000 | 200,000,000 | 150,000,000
Deferred tax assets, net |  |  |  | $ 132,231,000 |  | $ 92,904,000 |  |
Partial repurchase of convertible notes |  |  |  | 289,233,000 | $ 0 |  |  |
Loss on partial repurchase of convertible notes |  |  |  | 56,369,000 | 0 |  |  |
Payment for bonds hedge |  |  |  | 286,235,000 | 89,056,000 |  |  |
Proceeds from sale of warrants |  |  |  | 220,800,000 | $ 71,552,000 |  |  |
Warrants obligations measured at fair value |  |  |  |  |  |  | $ 96,400,000 |
Convertible Notes |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Convertible notes embedded derivative |  |  |  |  |  |  | 117,100,000 |
Convertible Notes | Convertible Senior Notes Due 2025 |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Debt instrument face amount |  | $ 320,000,000.0 |  |  |  |  |  |
Interest rate |  | 0.25% |  |  |  |  |  |
Debt conversion price (in USD per share) | $ / shares |  | $ 81.54 |  |  |  |  |  |
Proceeds from convertible debt |  | $ 313,000,000.0 |  |  |  |  |  |
Conversion ratio |  | 0.0122637 |  |  |  |  |  |
Debt, current |  |  |  | 102,300,000 |  |  |  |
Convertible notes embedded derivative |  | $ 68,700,000 |  |  |  |  | $ 116,300,000 |
Embedded derivative, host contract |  | 251,300,000 |  |  |  |  |  |
Deferred tax assets, net |  |  |  | $ 200,000 |  |  |  |
Debt issuance costs |  | $ 7,600,000 |  |  |  |  |  |
Partial repurchase of convertible notes | $ 217,700,000 |  |  |  |  |  |  |
Exercise of warrants (shares) | shares |  |  |  | 1,670,000 |  |  |  |
Equity component of convertible notes due 2025, net | 302,700,000 |  |  |  |  |  |  |
Convertible note, liability component | $ 184,500,000 |  |  |  |  |  |  |
Residual |  |  |  | $ 4,300,000 |  |  |  |
Induced conversion of convertible debt expense |  |  |  | $ 37,500,000 |  |  |  |
Remaining expected life |  |  |  | 4 years 1 month 6 days |  |  |  |
Write off of debt discount |  |  |  | $ 38,500,000 |  |  |  |
Write off of deferred debt issuance cost |  |  |  | 4,100,000 |  |  |  |
Loss on partial repurchase of convertible notes |  |  |  | $ 9,400,000 |  |  |  |
Effective percentage rate |  |  |  | 5.18% |  |  |  |
Unamortized discount |  |  |  | $ 17,700,000 |  | $ 58,600,000 |  |
Remaining discount amortization period |  |  |  | 3 years 10 months 24 days |  |  |  |
Conversion shares (in shares) | shares |  | 3,900,000 |  |  |  |  |  |
Payment for bonds hedge |  | $ 89,100,000 |  |  |  |  |  |
Warrants issued, strike price (in USD per share) | $ / shares |  | $ 106.94 |  |  |  |  |  |
Proceeds from sale of warrants |  | $ 71,600,000 |  |  |  |  |  |
Convertible notes hedge settlements, shares received (in shares) | shares |  |  |  | 1,900,000 |  |  |  |
Warrants unwound, shares issued (in shares) | shares |  |  |  | 1,800,000 |  |  |  |
Convertible notes hedge transaction, options outstanding (in shares) | shares |  |  |  | 1,300,000 |  |  |  |
Warrants outstanding (in shares) | shares |  |  |  | 1,300,000 |  |  |  |
Convertible Notes | Convertible Senior Notes Due 2025 | Subsequent Event |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Amount to be converted |  |  | $ 100,000 |  |  |  |  |
Convertible Notes | Convertible Senior Notes Due 2025 | Discount rate |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Measurement input |  |  |  | 0.0435 |  |  |  |
Period One | Convertible Notes | Convertible Senior Notes Due 2025 |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Number of threshold trading days | trading_day |  | 20 |  |  |  |  |  |
Number of consecutive trading days | trading_day |  | 30 |  |  |  |  |  |
Threshold percentage |  | 130.00% |  |  |  |  |  |
Stock trigger price (in USD per share) | $ / shares |  |  |  | $ 106.00 |  |  |  |
Period Two | Convertible Notes | Convertible Senior Notes Due 2025 |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Number of consecutive trading days | trading_day |  | 5 |  |  |  |  |  |
Threshold percentage |  | 100.00% |  |  |  |  |  |
Measurement period percentage of stock price trigger |  | 98.00% |  |  |  |  |  |

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