Fair Value of Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2020

Fair Value Disclosures [Abstract]

Summary of the valuation of cash equivalents and marketable securities by pricing levels

The following table presents the financial instruments that are carried at fair value and summarizes the valuation of its cash equivalents and marketable securities by the above pricing levels as of March 31, 2020 and December 31, 2019:

	As of March 31, 2020
(In thousands)	Total		Quoted  Market  Prices in  Active  Markets  (Level 1)		Significant  Other  Observable  Inputs  (Level 2)		Significant  Unobservable  Inputs  (Level 3)
Money market funds	$	22,143	$	22,143	$	—	$	—
U.S. Government bonds and notes	44,247		—		44,247		—
Corporate notes, bonds, commercial paper and other	323,639		—		323,639		—
Total available-for-sale securities	$	390,029	$	22,143	$	367,886	$	—

	As of December 31, 2019
(In thousands)	Total		Quoted  Market  Prices in  Active  Markets  (Level 1)		Significant  Other  Observable  Inputs  (Level 2)		Significant  Unobservable  Inputs  (Level 3)
Money market funds	$	10,065	$	10,065	$	—	$	—
U.S. Government bonds and notes	39,086		—		39,086		—
Corporate notes, bonds, commercial paper and other	314,391		—		314,391		—
Total available-for-sale securities	$	363,542	$	10,065	$	353,477	$	—

Financial instruments not carried at fair value but requiring fair value disclosure

The following table presents the financial instruments that are not carried at fair value but require fair value disclosure as of March 31, 2020 and December 31, 2019:

	As of March 31, 2020						As of December 31, 2019
(In thousands)	Face  Value		Carrying  Value		Fair Value		Face  Value		Carrying  Value		Fair Value
1.375% Convertible Senior Notes due 2023 (the “2023 Notes”)	$	172,500	$	150,561	$	166,468	$	172,500	$	148,788	$	174,239