The Company and Significant Accounting Policies - Summary of Amortized Cost and Unrealized (Gains) Losses of Available for Sale Securities (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2019 USD ($)
Certificates of Deposit
Amortized Cost
Due within a year	$ 3,766
Due after one year through five years	3,036
Total	6,802
Unrealized gains (losses)
Due within a year	15
Due after one year through five years	24
Total	39
Corporate Bonds
Amortized Cost
Due within a year	45,000
Due after one year through five years	55,096
Total	100,096
Unrealized gains (losses)
Due within a year	168
Due after one year through five years	381
Total	$ 549