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v3.19.1

Condensed Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands | Total | Common Stock [Member] | Additional Paid-in Capital [Member] | Accumulated Other Comprehensive Loss [Member] | Retained Earnings [Member]
--- | --- | --- | --- | --- | ---
Balance at Dec. 31, 2017 | $ 3,066,454 | $ 937 | $ 1,017,328 |  | $ 2,048,189
Balance, Shares at Dec. 31, 2017 |  | 93,721 |  |  |
Net income (loss) | 63,428 |  |  |  | 63,428
Common stock issued under employee stock option, employee stock purchase plan and stock purchase plan | 4,027 | $ 1 | 4,026 |  |
Common stock issued under employee stock option, employee stock purchase plan and stock purchase plan, shares |  | 97 |  |  |
Issuance of restricted stock |  | $ 6 | (6) |  |
Issuance of restricted stock, shares |  | 588 |  |  |
Forfeitures of restricted stock, shares |  | (13) |  |  |
Stock swaps | (296) |  | (296) |  |
Stock swaps,shares |  | (5) |  |  |
Stock-based compensation expense | 9,875 |  | 9,875 |  |
Balance at Mar. 31, 2018 | 3,143,488 | $ 944 | 1,030,927 |  | 2,111,617
Balance, Shares at Mar. 31, 2018 |  | 94,388 |  |  |
Balance at Dec. 31, 2017 | 3,066,454 | $ 937 | 1,017,328 |  | 2,048,189
Balance, Shares at Dec. 31, 2017 |  | 93,721 |  |  |
Repurchased common stock | (250,000) |  |  |  |
Balance at Dec. 31, 2018 | 3,087,884 | $ 878 | 992,647 |  | 2,094,359
Balance, Shares at Dec. 31, 2018 |  | 87,820 |  |  |
Net income (loss) | (242,872) |  |  |  | (242,872)
Unrealized holding loss on investments, net of tax | (194) |  |  | $ (194) |
Common stock issued under employee stock option, employee stock purchase plan and stock purchase plan | 3,542 | $ 1 | 3,541 |  |
Common stock issued under employee stock option, employee stock purchase plan and stock purchase plan, shares |  | 140 |  |  |
Issuance of restricted stock |  | $ 10 | (10) |  |
Issuance of restricted stock, shares |  | 978 |  |  |
Forfeitures of restricted stock, shares |  | (6) |  |  |
Stock swaps | (666) |  | (666) |  |
Stock swaps,shares |  | (20) |  |  |
Stock-based compensation expense | 11,100 |  | 11,100 |  |
Repurchased common stock | (78,982) | $ (25) | (28,740) |  | (50,217)
Repurchased common stock, shares |  | (2,525) |  |  |
Balance at Mar. 31, 2019 | $ 2,779,812 | $ 864 | $ 977,872 | $ (194) | $ 1,801,270
Balance, Shares at Mar. 31, 2019 |  | 86,387 |  |  |

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