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Stock-Based Compensation - Performance-based Awards (Details) - USD ($) shares in Thousands, $ in Thousands | 3 Months Ended | 9 Months Ended
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Sep. 30, 2021 | Jun. 30, 2021 | Mar. 31, 2021 | Dec. 31, 2020 | Sep. 30, 2020 | Jun. 30, 2020 | Mar. 31, 2020 | Sep. 30, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Sep. 30, 2021 | Sep. 30, 2020
Fair Market Value |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Valuation Method |  | Fair Market Value | Fair Market Value | Fair Market Value | Fair Market Value | Fair Market Value | Fair Market Value |  | Fair Market Value |  |  |
Black-Scholes Merton |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Valuation Method |  | Black-Scholes-Merton |  |  | Black-Scholes-Merton |  | Black-Scholes-Merton |  |  |  |  |
Monte-Carlo |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Valuation Method |  | Monte-Carlo Simulation | Monte-Carlo Simulation | Monte-Carlo Simulation |  |  | Monte-Carlo Simulation | Monte-Carlo Simulation |  | Monte-Carlo Simulation |  |
Performance-based awards |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Stock-based compensation expense | $ 9,600 |  |  |  | $ 6,600 |  |  |  |  |  | $ 39,500 | $ 11,800
Restricted stock units |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
RSUs Granted (in shares) |  |  |  |  |  |  |  |  |  |  | 1,528 |
Vested (in shares) |  |  |  |  |  |  |  |  |  |  | 1,707 |
Restricted stock units | Fair Market Value |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
RSUs Granted (in shares) |  | 7 | 279 | 22 | 27 | 21 | 436 |  | 188 |  |  |
Vested (in shares) |  |  | 10 | 2 | 17 | 21 | 406 |  | 81 |  |  |
Restricted stock units | Monte-Carlo |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
RSUs Granted (in shares) |  |  | 125 | 32 |  |  | 300 | 50 |  | 300 |  |
Vested (in shares) |  |  |  | 6 |  |  | 225 | 50 |  | 300 |  |
Employee and non-employee stock options |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Options Granted (in shares) |  |  |  |  |  |  |  |  |  |  | 391 |
RSUs Granted (in shares) |  |  |  |  |  |  |  |  |  |  | 1,528 |
Stock-based compensation expense | $ 26,459 |  |  |  | $ 15,032 |  |  |  |  |  | $ 84,797 | $ 34,406
Employee and non-employee stock options | Black-Scholes Merton |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Options Granted (in shares) |  | 29 |  |  | 10 |  | 129 |  |  |  |  |
Options Vested (in shares) |  |  |  |  | 10 |  | 129 |  |  |  |  |
Employee and non-employee stock options | Monte-Carlo |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Options Granted (in shares) |  | 163 | 150 |  |  |  | 150 |  |  | 200 |  |
Options Vested (in shares) |  |  |  |  |  |  | 113 |  |  | 201 |  |

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- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5047-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(2) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition Description of method used to estimate fair value of award under share-based payment arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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