Available-for-Sale Marketable Securities in Unrealized Position (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	$ 4,072
Less than 12 Months, Unrealized Loss	(2)
Total, Fair Value	4,072
Total, Unrealized Loss	(2)
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	3,073	$ 5,105
Less than 12 Months, Unrealized Loss	(1)	(3)
Total, Fair Value	3,073	5,105
Total, Unrealized Loss	(1)	$ (3)
United States government agency securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	999
Less than 12 Months, Unrealized Loss	(1)
Total, Fair Value	999
Total, Unrealized Loss	$ (1)