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Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2020 | Sep. 30, 2020 | Jun. 30, 2020 | Mar. 31, 2020 | Dec. 31, 2019 | Sep. 30, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |  |
Revenues: | $ 25,337 | $ 23,409 | $ 26,106 | $ 47,488 | $ 47,667 | $ 65,690 | $ 67,941 | $ 51,775 | $ 122,340 | $ 233,073 | $ 212,470
Cost of goods sold | 32,999 | 18,227 | 11,906 | 41,089 | 29,793 | 38,555 | 43,068 | 40,605 | 104,221 | 152,021 | 143,103
Operating expenses | 13,294 | 6,431 | 5,546 | 5,865 | 13,995 | 12,687 | 5,668 | 5,219 | 31,136 | 37,569 | 41,688
Net income | $ (2,884) | $ 36,282 | $ 4,640 | $ (84) | $ 2,388 | $ 10,926 | $ 14,276 | $ 4,033 | $ 37,954 | $ 31,623 | $ 20,101
Basic (in dollars per share) | $ (0.07) | $ 0.91 | $ 0.12 | $ 0 | $ 0.06 | $ 0.27 | $ 0.36 | $ 0.10 | $ 0.94 | $ 0.79 | $ 0.50
Diluted (in dollars per share) | $ (0.07) | $ 0.91 | $ 0.12 | $ 0 | $ 0.05 | $ 0.27 | $ 0.36 | $ 0.10 | $ 0.94 | $ 0.78 | $ 0.50

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