Fair Value Measurements - Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value Measurements Recurring - USD ($) |
Mar. 31, 2022 |
Dec. 31, 2021 |
|---|---|---|
| Assets: | ||
| Total | $ 229,300,000 | $ 265,750,000 |
| Level 1 | ||
| Assets: | ||
| Total | 113,133,000 | 114,052,000 |
| Level 2 | ||
| Assets: | ||
| Total | 116,167,000 | 151,698,000 |
| Level 3 | ||
| Assets: | ||
| Total | 0 | 0 |
| Money Market Funds | ||
| Assets: | ||
| Total | 28,358,000 | 29,451,000 |
| Money Market Funds | Level 1 | ||
| Assets: | ||
| Total | 28,358,000 | 29,451,000 |
| Commercial Paper | ||
| Assets: | ||
| Total | 25,179,000 | 22,580,000 |
| Commercial Paper | Level 2 | ||
| Assets: | ||
| Total | 25,179,000 | 22,580,000 |
| Corporate Debt Securities | ||
| Assets: | ||
| Total | 49,511,000 | 74,861,000 |
| Corporate Debt Securities | Level 2 | ||
| Assets: | ||
| Total | 49,511,000 | 74,861,000 |
| Equity Securities | ||
| Assets: | ||
| Total | 37,744,000 | 37,181,000 |
| Equity Securities | Level 1 | ||
| Assets: | ||
| Total | 37,744,000 | 37,181,000 |
| Asset-backed Securities | ||
| Assets: | ||
| Total | 20,398,000 | 32,957,000 |
| Asset-backed Securities | Level 2 | ||
| Assets: | ||
| Total | 20,398,000 | 32,957,000 |
| U.S. Government Securities | ||
| Assets: | ||
| Total | 47,031,000 | 47,420,000 |
| U.S. Government Securities | Level 1 | ||
| Assets: | ||
| Total | 47,031,000 | 47,420,000 |
| Supranational Debt Securities | ||
| Assets: | ||
| Total | 21,079,000 | 21,300,000 |
| Supranational Debt Securities | Level 2 | ||
| Assets: | ||
| Total | $ 21,079,000 | $ 21,300,000 |