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Stockholders' Equity - ESPP Activity (Details) - $ / shares shares in Thousands | 12 Months Ended
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Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Equity [Abstract] |  |  |
Number of shares issued (in thousands) | 131 | 116 | 130
Weighted average price (usd per share) | $ 195.44 | $ 175.69 | $ 136.73

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