Quarterly report pursuant to Section 13 or 15(d)

Financial Instruments - Amortized Cost and Fair Value of Available-for-Sale Securities by Contractual Maturity (Detail)

v3.19.1
Financial Instruments - Amortized Cost and Fair Value of Available-for-Sale Securities by Contractual Maturity (Detail) - USD ($)
$ in Thousands
Mar. 31, 2019
Dec. 31, 2018
Amortized cost    
Maturing within one year, Amortized cost $ 216,066 $ 287,755
Maturing in one to five years, Amortized cost 15,730 23,169
Total available-for-sale securities, Amortized cost 231,796 310,924
Estimated Fair value    
Maturing within one year, Estimated fair value 216,062 287,469
Maturing in one to five years, Estimated fair value 15,772 23,115
Total available-for-sale securities, Estimated fair value $ 231,834 $ 310,584