Fair Value Measurements - Fair value hierarchy (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Financial Instruments Measurements
Transfers between Level 1, Level 2 and Level 3	$ 0	$ 0
Summary of assets measured at fair value on a recurring basis
Total	207,856	40,853
Level 1
Summary of assets measured at fair value on a recurring basis
Total	7,924	1,853
Level 2
Summary of assets measured at fair value on a recurring basis
Total	199,932	39,000
Money market funds
Summary of assets measured at fair value on a recurring basis
Cash and cash equivalents	1,944	1,853
Money market funds | Level 1
Summary of assets measured at fair value on a recurring basis
Cash and cash equivalents	1,944	1,853
Corporate debt securities
Summary of assets measured at fair value on a recurring basis
Short term investments	16,445
Corporate debt securities | Level 2
Summary of assets measured at fair value on a recurring basis
Short term investments	16,445
Yankee securities
Summary of assets measured at fair value on a recurring basis
Short term investments	1,999
Yankee securities | Level 2
Summary of assets measured at fair value on a recurring basis
Short term investments	1,999
Bonds
Summary of assets measured at fair value on a recurring basis
Short term investments	2,988
Bonds | Level 2
Summary of assets measured at fair value on a recurring basis
Short term investments	2,988
Treasury bill
Summary of assets measured at fair value on a recurring basis
Short term investments	5,980
Treasury bill | Level 1
Summary of assets measured at fair value on a recurring basis
Short term investments	5,980
Reverse repurchase agreements
Summary of assets measured at fair value on a recurring basis
Short term investments	178,500	39,000
Reverse repurchase agreements | Level 2
Summary of assets measured at fair value on a recurring basis
Short term investments	$ 178,500	$ 39,000