Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	$ 552,630	$ 390,323
Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents maturity term	3 months
U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	$ 221,724	143,254
Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	218,381	108,896
Corporate debt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	58,836	85,823
Supranational bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	3,003
Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	600,916	477,623
Common stock warrants	147	14,261
Total liabilities	147	14,261
Fair Value, Measurements, Recurring | Cash equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	48,286	87,300
Fair Value, Measurements, Recurring | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	221,724	143,254
Fair Value, Measurements, Recurring | Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	218,381	108,896
Fair Value, Measurements, Recurring | U.S. Government-sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	50,686	52,350
Fair Value, Measurements, Recurring | Corporate debt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	58,836	85,823
Fair Value, Measurements, Recurring | Supranational bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	3,003
Fair Value, Measurements, Recurring | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	270,010	230,554
Common stock warrants	0	0
Total liabilities	0	0
Fair Value, Measurements, Recurring | Level 1 | Cash equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	48,286	87,300
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	221,724	143,254
Fair Value, Measurements, Recurring | Level 1 | Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 1 | U.S. Government-sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	0	0
Fair Value, Measurements, Recurring | Level 1 | Corporate debt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	0	0
Fair Value, Measurements, Recurring | Level 1 | Supranational bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	330,906	247,069
Common stock warrants	0	0
Total liabilities	0	0
Fair Value, Measurements, Recurring | Level 2 | Cash equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 2 | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	0	0
Fair Value, Measurements, Recurring | Level 2 | Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	218,381	108,896
Fair Value, Measurements, Recurring | Level 2 | U.S. Government-sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	50,686	52,350
Fair Value, Measurements, Recurring | Level 2 | Corporate debt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	58,836	85,823
Fair Value, Measurements, Recurring | Level 2 | Supranational bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	3,003
Fair Value, Measurements, Recurring | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total assets	0	0
Common stock warrants	147	14,261
Total liabilities	147	14,261
Fair Value, Measurements, Recurring | Level 3 | Cash equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. Treasury securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	0	0
Fair Value, Measurements, Recurring | Level 3 | Commercial paper
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Level 3 | U.S. Government-sponsored enterprises
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	0	0
Fair Value, Measurements, Recurring | Level 3 | Corporate debt securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	0	$ 0
Fair Value, Measurements, Recurring | Level 3 | Supranational bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt securities, available for sale	$ 0