Fair Value Measurements - Additional Information (Detail) - Position	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, investments in unrealized loss positions, number of positions		15
Available-for-sale, investments in unrealized loss positions, number of positions, less than twelve months		25
Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments effective maturity period	2 years