Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 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 December 31, 2020 and 2019:

	As of December 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	$	32,815	$	32,815	$	—	$	—
U.S. Government bonds and notes	169,880		—		169,880		—
Corporate notes, bonds and commercial paper	238,491		—		238,491		—
Total available-for-sale securities	$	441,186	$	32,815	$	408,371	$	—

	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	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 which require fair value disclosure as of December 31, 2020 and 2019:

	As of December 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	$	156,031	$	194,709	$	172,500	$	148,788	$	174,239