Short-term Investments - Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Amortized cost	$ 242,140	$ 28,800
Gross unrealized gains	5	83
Gross unrealized losses	(324)	0
Fair value	241,821	28,883
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	70,393
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(59)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	67,287
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(265)
Debt Securities, Available-for-sale, Unrealized Loss Position	137,680
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(324)
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized cost	177,375	22,338
Gross unrealized gains	3	71
Gross unrealized losses	(195)	0
Fair value	177,183	22,409
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	28,720
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(8)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	49,347
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(187)
Debt Securities, Available-for-sale, Unrealized Loss Position	78,067
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(195)
U.S. government-related debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized cost	33,134	5,000
Gross unrealized gains	2	3
Gross unrealized losses	(97)	0
Fair value	33,039	5,003
Asset-backed Securities
Debt Securities, Available-for-sale [Line Items]
Amortized cost	31,631	1,462
Gross unrealized gains	0	9
Gross unrealized losses	(32)	0
Fair value	31,599	$ 1,471
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	31,599
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(32)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0
Debt Securities, Available-for-sale, Unrealized Loss Position	31,599
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(32)
US Government Debt Securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	10,074
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(19)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	17,940
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(78)
Debt Securities, Available-for-sale, Unrealized Loss Position	28,014
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (97)