The Company and Significant Accounting Policies - Summary of Amortized Cost and Unrealized (Gains) Losses of Available for Sale Securities (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($)
Certificates of Deposit
Amortized Cost
Due within a year	$ 2,880
Due after one year through five years	4,882
Total	7,762
Unrealized gains (losses)
Due within a year	1
Due after one year through five years	19
Total	20
Corporate Bonds
Amortized Cost
Due within a year	29,997
Due after one year through five years	75,206
Total	105,203
Unrealized gains (losses)
Due within a year	41
Due after one year through five years	323
Total	$ 364