Fair Value Measurements - Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair value
Total investment securities	$ 73,835	$ 96,420
Commercial paper
Fair value
Total investment securities	14,930	15,986
Corporate notes / bonds
Fair value
Total investment securities	46,946	46,493
Money market funds
Fair value
Total investment securities	5,741	5,374
U.S. govt. agencies
Fair value
Total investment securities	3,459	18,165
U.S. treasuries
Fair value
Total investment securities	2,759	10,402
Recurring
Fair value
Total investment securities	73,835	96,420
Recurring | Commercial paper
Fair value
Total investment securities	14,930	15,986
Recurring | Corporate notes / bonds
Fair value
Total investment securities	46,946	46,493
Recurring | Money market funds
Fair value
Total investment securities	5,741	5,374
Recurring | U.S. govt. agencies
Fair value
Total investment securities	3,459	18,165
Recurring | U.S. treasuries
Fair value
Total investment securities	2,759	10,402
Recurring | Level 1
Fair value
Total investment securities	11,959	33,941
Recurring | Level 1 | Money market funds
Fair value
Total investment securities	5,741	5,374
Recurring | Level 1 | U.S. govt. agencies
Fair value
Total investment securities	3,459	18,165
Recurring | Level 1 | U.S. treasuries
Fair value
Total investment securities	2,759	10,402
Recurring | Level 2
Fair value
Total investment securities	61,876	62,479
Recurring | Level 2 | Commercial paper
Fair value
Total investment securities	14,930	15,986
Recurring | Level 2 | Corporate notes / bonds
Fair value
Total investment securities	$ 46,946	$ 46,493