| Additional Balance Sheet Detail |
Additional Balance Sheet Detail Accrued expenses consisted of the following: | | | | | | | | | | As of December 31, | | 2019 | | 2018 | | (in thousands) | Payroll and benefits | $ | 159,464 |
| | $ | 124,753 |
| Research, development and commercial contract costs | 105,663 |
| | 115,300 |
| Product revenue allowances | 641,368 |
| | 550,002 |
| Royalty payable | 98,578 |
| | 101,108 |
| Tax related accruals | 72,293 |
| | 43,281 |
| Other | 39,546 |
| | 24,455 |
| Total | $ | 1,116,912 |
| | $ | 958,899 |
|
Other current liabilities consisted of the following: | | | | | | | | | | As of December 31, | | 2019 | | 2018 | | (in thousands) | Contract liabilities | $ | 62,332 |
| | $ | 24,870 |
| Finance lease liabilities | 30,293 |
| | 5,271 |
| Other | 37,680 |
| | 20,265 |
| Total | $ | 130,305 |
| | $ | 50,406 |
|
Other long-term liabilities consisted of the following: | | | | | | | | | | As of December 31, | | 2019 | | 2018 | | (in thousands) | Advance from collaborator | $ | 88,762 |
| | $ | 82,573 |
| Operating lease liabilities | 84,292 |
| | — |
| Other | 10,264 |
| | 26,280 |
| Total | $ | 183,318 |
| | $ | 108,853 |
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