Cash, Cash Equivalents and Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2020

Cash and Cash Equivalents [Abstract]

Amortized Cost and Fair Value of Cash, Cash Equivalents and Marketable Securities

The following table summarizes the amortized cost and fair value of our cash, cash equivalents and marketable securities by major investment category as of December 31, 2020 and 2019:

	December 31, 2020
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Current assets:
Cash	$	23,887	$	—	$	—	$	23,887
Cash equivalents:
Money market funds	80,986		—		—		80,986
Commercial paper	61,043		—		—		61,043
Certificate of deposits	1,000		—		—		1,000
Total cash equivalents	143,029		—		—		143,029
Total cash and cash equivalents	166,916		—		—		166,916
Marketable securities:
U.S. Treasuries	43,050		1		(1)		43,050
Commercial paper	210,986		—		—		210,986
Certificate of deposits	44,480		—		—		44,480
U.S. Government-sponsored enterprises debt securities	6,200		17		—		6,217
Corporate debt securities	33,288		172		—		33,460
Total marketable securities	338,004		190		(1)		338,193
Total cash, cash equivalents and marketable securities	$	504,920	$	190	$	(1)	$	505,109

	December 31, 2019
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Current assets:
Cash	$	43,058	$	—	$	—	$	43,058
Cash equivalents:
Money market funds	11,527		—		—		11,527
Commercial paper	7,485		—		—		7,485
Total cash and cash equivalents	62,070		—		—		62,070
Marketable securities:
Commercial paper	73,366		—		—		73,366
Corporate debt securities	74,038		381		(2)		74,417
Certificates of deposit	41,302		—		—		41,302
Total marketable securities	188,706		381		(2)		189,085
Total cash, cash equivalents and marketable securities	$	250,776	$	381	$	(2)	$	251,155

Cost and Fair Values of Marketable Securities

The following table summarizes the amortized cost and fair value of marketable securities based on stated effective maturities as of December 31, 2020:

(In thousands)	Amortized Cost		Estimated Fair Value
Due within one year	$	331,804	$	331,976
Due between one and two years	6,200		6,217
Total	$	338,004	$	338,193