Fair value measurements - Recorded Amount of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Assets:
Marketable securities:	$ 231,767,000	$ 0
U.S. government agency securities and treasuries
Assets:
Marketable securities:	128,392,000
Corporate bonds
Assets:
Marketable securities:	49,310,000
Commercial paper
Assets:
Marketable securities:	54,065,000
Fair value, measurements, recurring
Assets:
Cash and cash equivalents	130,414,000
Total assets	362,181,000	0
Liabilities:
Contingent consideration	1,948,000	1,509,000
Total liabilities	1,948,000	1,509,000
Fair value, measurements, recurring | U.S. government agency securities and treasuries
Assets:
Marketable securities:	128,392,000
Fair value, measurements, recurring | Corporate bonds
Assets:
Marketable securities:	49,310,000
Fair value, measurements, recurring | Commercial paper
Assets:
Marketable securities:	54,065,000
Fair value, measurements, recurring | Quoted prices in active markets (Level 1)
Assets:
Cash and cash equivalents	130,414,000
Total assets	130,414,000
Liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Fair value, measurements, recurring | Quoted prices in active markets (Level 1) | U.S. government agency securities and treasuries
Assets:
Marketable securities:	0
Fair value, measurements, recurring | Quoted prices in active markets (Level 1) | Corporate bonds
Assets:
Marketable securities:	0
Fair value, measurements, recurring | Quoted prices in active markets (Level 1) | Commercial paper
Assets:
Marketable securities:	0
Fair value, measurements, recurring | Significant other observable inputs (Level 2)
Assets:
Cash and cash equivalents	0
Total assets	231,767,000
Liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Fair value, measurements, recurring | Significant other observable inputs (Level 2) | U.S. government agency securities and treasuries
Assets:
Marketable securities:	128,392,000
Fair value, measurements, recurring | Significant other observable inputs (Level 2) | Corporate bonds
Assets:
Marketable securities:	49,310,000
Fair value, measurements, recurring | Significant other observable inputs (Level 2) | Commercial paper
Assets:
Marketable securities:	54,065,000
Fair value, measurements, recurring | Significant unobservable inputs (Level 3)
Assets:
Cash and cash equivalents	0
Total assets	0
Liabilities:
Contingent consideration	1,948,000	1,509,000
Total liabilities	1,948,000	$ 1,509,000
Fair value, measurements, recurring | Significant unobservable inputs (Level 3) | U.S. government agency securities and treasuries
Assets:
Marketable securities:	0
Fair value, measurements, recurring | Significant unobservable inputs (Level 3) | Corporate bonds
Assets:
Marketable securities:	0
Fair value, measurements, recurring | Significant unobservable inputs (Level 3) | Commercial paper
Assets:
Marketable securities:	$ 0