Fair Value Measurements - Fair Value of Financial Assets Measured on Recurring Basis (Details) - Fair Value Measurements Recurring - USD ($)	Mar. 31, 2023	Dec. 31, 2022
Assets:
Total	$ 275,125,000	$ 330,430,000
Level 1
Assets:
Total	165,564,000	159,757,000
Level 2
Assets:
Total	109,561,000	170,673,000
Level 3
Assets:
Total	0	0
Money Market Funds
Assets:
Total	46,137,000	36,486,000
Money Market Funds | Level 1
Assets:
Total	46,137,000	36,486,000
Commercial Paper
Assets:
Total	73,834,000	87,140,000
Commercial Paper | Level 2
Assets:
Total	73,834,000	87,140,000
Corporate Debt Securities
Assets:
Total	17,863,000	36,429,000
Corporate Debt Securities | Level 2
Assets:
Total	17,863,000	36,429,000
Equity Securities
Assets:
Total	25,028,000	32,020,000
Equity Securities | Level 1
Assets:
Total	25,028,000	32,020,000
Asset-backed Securities
Assets:
Total	6,562,000	14,016,000
Asset-backed Securities | Level 2
Assets:
Total	6,562,000	14,016,000
U.S. Government Securities
Assets:
Total	94,399,000	91,251,000
U.S. Government Securities | Level 1
Assets:
Total	94,399,000	91,251,000
U.S. Agency Securities
Assets:
Total	6,750,000	16,607,000
U.S. Agency Securities | Level 2
Assets:
Total	6,750,000	16,607,000
Supranational Debt Securities
Assets:
Total	4,552,000	16,481,000
Supranational Debt Securities | Level 2
Assets:
Total	$ 4,552,000	$ 16,481,000