Fair Value Measurement - Summary of Contractual Maturities of Available for Sale Securities (Detail) $ in Thousands	Jun. 30, 2019 USD ($)
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	$ 51,207
Available for sale securities, contractual maturities between 1 to 5 years	173,253
Available for sale securities, contractual maturities between 5 to 10 years	52,600
Available for sale securities, contractual maturities after 10 years	152
Available for sale securities, contractual maturities, Total	277,212
Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	9,162
Available for sale securities, contractual maturities between 1 to 5 years	143,773
Available for sale securities, contractual maturities between 5 to 10 years	24,886
Available for sale securities, contractual maturities after 10 years	152
Available for sale securities, contractual maturities, Total	177,973
U.S. Treasuries [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	21,155
Available for sale securities, contractual maturities between 1 to 5 years	16,612
Available for sale securities, contractual maturities, Total	37,767
U.S. Government Agency Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	4,002
Available for sale securities, contractual maturities between 1 to 5 years	7,921
Available for sale securities, contractual maturities between 5 to 10 years	27,714
Available for sale securities, contractual maturities, Total	39,637
Money Market Funds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	16,838
Available for sale securities, contractual maturities, Total	16,838
Supranational Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities between 1 to 5 years	4,801
Available for sale securities, contractual maturities, Total	4,801
Asset Backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities between 1 to 5 years	146
Available for sale securities, contractual maturities, Total	146
Municipal Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, contractual maturities less than 1 year	50
Available for sale securities, contractual maturities, Total	$ 50

Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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