Significant Accounting Policies - Estimated Fair Value of Assets and Liability (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Asset:
Asset, fair value	$ 192,307	$ 374,911
Level 1
Asset:
Asset, fair value	86,541	118,282
Level 2
Asset:
Asset, fair value	105,766	256,629
Money Market Fund
Asset:
Asset, fair value	81,870	95,063
Money Market Fund | Level 1
Asset:
Asset, fair value	81,870	95,063
U.S. Treasury Shares
Asset:
Asset, fair value	3,117	23,219
U.S. Treasury Shares | Level 1
Asset:
Asset, fair value	3,117	23,219
Agency Securities
Asset:
Asset, fair value	1,554
Agency Securities | Level 1
Asset:
Asset, fair value	1,554
Corporate Bonds
Asset:
Asset, fair value	28,416	83,587
Corporate Bonds | Level 2
Asset:
Asset, fair value	28,416	83,587
Commercial Paper
Asset:
Asset, fair value	62,347	121,773
Commercial Paper | Level 2
Asset:
Asset, fair value	62,347	121,773
Repo Securities
Asset:
Asset, fair value	3,250	8,000
Repo Securities | Level 2
Asset:
Asset, fair value	3,250	8,000
Asset Backed Securities
Asset:
Asset, fair value	1,260	8,816
Asset Backed Securities | Level 2
Asset:
Asset, fair value	1,260	8,816
Certificate of Deposit
Asset:
Asset, fair value	9,100	21,553
Certificate of Deposit | Level 2
Asset:
Asset, fair value	9,100	21,553
Non-US Government
Asset:
Asset, fair value	1,393	12,900
Non-US Government | Level 2
Asset:
Asset, fair value	$ 1,393	$ 12,900