Fair Value Measurements - Assets and Liabilities Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Financial assets:
Total financial assets	$ 338,491	$ 389,390
Cash, cash equivalents and restricted cash
Financial assets:
Total financial assets	46,397	94,172
U.S. agency securities
Financial assets:
Total financial assets		4,948
Corporate bonds
Financial assets:
Total financial assets	32,396	104,080
Commercial paper
Financial assets:
Total financial assets	93,916	125,187
Treasury bills
Financial assets:
Total financial assets	80,213	12,282
Treasury bonds
Financial assets:
Total financial assets	85,569	42,220
Yankee bonds
Financial assets:
Total financial assets	0	6,501
Level 1
Financial assets:
Total financial assets	46,397	94,172
Level 1 | Cash, cash equivalents and restricted cash
Financial assets:
Total financial assets	46,397	94,172
Level 1 | U.S. agency securities
Financial assets:
Total financial assets		0
Level 1 | Corporate bonds
Financial assets:
Total financial assets	0	0
Level 1 | Commercial paper
Financial assets:
Total financial assets	0	0
Level 1 | Treasury bills
Financial assets:
Total financial assets	0	0
Level 1 | Treasury bonds
Financial assets:
Total financial assets	0	0
Level 1 | Yankee bonds
Financial assets:
Total financial assets	0	0
Level 2
Financial assets:
Total financial assets	$ 292,094	$ 295,218
Derivative, average remaining maturity	7 months	7 months
Level 2 | Cash, cash equivalents and restricted cash
Financial assets:
Total financial assets	$ 0	$ 0
Level 2 | U.S. agency securities
Financial assets:
Total financial assets		4,948
Level 2 | Corporate bonds
Financial assets:
Total financial assets	32,396	104,080
Level 2 | Commercial paper
Financial assets:
Total financial assets	93,916	125,187
Level 2 | Treasury bills
Financial assets:
Total financial assets	80,213	12,282
Level 2 | Treasury bonds
Financial assets:
Total financial assets	85,569	42,220
Level 2 | Yankee bonds
Financial assets:
Total financial assets	0	6,501
Level 3
Financial assets:
Total financial assets	0	0
Level 3 | Cash, cash equivalents and restricted cash
Financial assets:
Total financial assets	0	0
Level 3 | U.S. agency securities
Financial assets:
Total financial assets		0
Level 3 | Corporate bonds
Financial assets:
Total financial assets	0	0
Level 3 | Commercial paper
Financial assets:
Total financial assets	0	0
Level 3 | Treasury bills
Financial assets:
Total financial assets	0	0
Level 3 | Treasury bonds
Financial assets:
Total financial assets	0	0
Level 3 | Yankee bonds
Financial assets:
Total financial assets	$ 0	$ 0