Investments (Tables)
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12 Months Ended |
Dec. 31, 2019 |
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| Debt Securities, Available-for-sale [Abstract] |
|
| Summary of Investments |
The following is a summary of our available-for-sale debt securities recorded within short-term and long-term investments on the consolidated balance sheets (in thousands): | | | | | | | | | | | | | | | | | | December 31, 2019 | | Amortized Cost | | Gross Unrealized Gains | | Gross Unrealized Losses | | Estimated Fair Value | Available-for-sale securities: | | | | | | | | Commercial paper | $ | 101,416 |
| | $ | 83 |
| | $ | (9 | ) | | $ | 101,490 |
| Corporate notes and bonds | 1,654,166 |
| | 7,360 |
| | (196 | ) | | 1,661,330 |
| Certificates of deposit | 38,007 |
| | 38 |
| | — |
| | 38,045 |
| U.S. government and agency securities | 127,544 |
| | 254 |
| | (14 | ) | | 127,784 |
| Total available-for-sale securities | $ | 1,921,133 |
| | $ | 7,735 |
| | $ | (219 | ) | | $ | 1,928,649 |
|
| | | | | | | | | | | | | | | | | | December 31, 2018 | | Amortized Cost | | Gross Unrealized Gains | | Gross Unrealized Losses | | Estimated Fair Value | Available-for-sale securities: | | | | | | | | Commercial paper | $ | 108,061 |
| | $ | — |
| | $ | — |
| | $ | 108,061 |
| Corporate notes and bonds | 1,233,589 |
| | 343 |
| | (4,218 | ) | | 1,229,714 |
| Certificates of deposit | 73,584 |
| | 1 |
| | — |
| | 73,585 |
| U.S. government and agency securities | 102,549 |
| | 23 |
| | (358 | ) | | 102,214 |
| Total available-for-sale securities | $ | 1,517,783 |
| | $ | 367 |
| | $ | (4,576 | ) | | $ | 1,513,574 |
|
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| Investments Classified by Contractual Maturity Date |
The fair values of available-for-sale investment securities, by remaining contractual maturity, are as follows (in thousands): | | | | | | December 31, 2019 | Due within 1 year | $ | 915,317 |
| Due in 1 year through 5 years | 1,013,332 |
| Total | $ | 1,928,649 |
|
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| Fair Values and Gross Unrealized Losses of Available-for-Sale Securities Aggregated by Investment Category |
The following table shows the fair values and the gross unrealized losses of these available-for-sale debt securities, classified by the length of time that the securities have been in a continuous unrealized loss position, and aggregated by investment types, excluding those securities classified within cash and cash equivalents on the consolidated balance sheets (in thousands): | | | | | | | | | | | | | | | | | | | | | | | | | | December 31, 2019 | | Less than 12 Months | | 12 Months or Greater | | Total | | Fair Value | | Gross Unrealized Losses | | Fair Value | | Gross Unrealized Losses | | Fair Value | | Gross Unrealized Losses | Commercial paper | $ | 20,752 |
| | $ | (9 | ) | | $ | — |
| | $ | — |
| | $ | 20,752 |
| | $ | (9 | ) | Corporate notes and bonds | 242,012 |
| | (181 | ) | | 16,264 |
| | (15 | ) | | 258,276 |
| | (196 | ) | U.S. government and agency securities | 17,806 |
| | (14 | ) | | — |
| | — |
| | 17,806 |
| | (14 | ) | Total | $ | 280,570 |
| | $ | (204 | ) | | $ | 16,264 |
| | $ | (15 | ) | | $ | 296,834 |
| | $ | (219 | ) |
| | | | | | | | | | | | | | | | | | | | | | | | | | December 31, 2018 | | Less than 12 Months | | 12 Months or Greater | | Total | | Fair Value | | Gross Unrealized Losses | | Fair Value | | Gross Unrealized Losses | | Fair Value | | Gross Unrealized Losses | Corporate notes and bonds | $ | 714,605 |
| | $ | (2,603 | ) | | $ | 294,956 |
| | $ | (1,615 | ) | | $ | 1,009,561 |
| | $ | (4,218 | ) | Certificates of deposit | 1,000 |
| | — |
| | — |
| | — |
| | 1,000 |
| | — |
| U.S. government and agency securities | 11,756 |
| | (5 | ) | | 61,457 |
| | (353 | ) | | 73,213 |
| | (358 | ) | Total | $ | 727,361 |
| | $ | (2,608 | ) | | $ | 356,413 |
| | $ | (1,968 | ) | | $ | 1,083,774 |
| | $ | (4,576 | ) |
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