Short-term Investments (Tables)

9 Months Ended

Sep. 30, 2021

Investments, Debt and Equity Securities [Abstract]

Debt Securities, Available-for-sale

Short-term investments consisted of available-for-sale and equity securities as follows (in thousands):

Type of securities as of September 30, 2021	Amortized cost		Gross unrealized gains		Gross unrealized losses		Fair value
Corporate debt securities	$	197,737	$	17	$	(22)	$	197,732
Government-related debt securities	33,186		—		(12)		33,174
Asset-backed securities	31,788		2		(9)		31,781
Total available-for-sale debt securities	$	262,711	$	19	$	(43)	$	262,687

Type of securities as of December 31, 2020	Amortized cost		Gross unrealized gains		Gross unrealized losses		Fair value
Corporate debt securities	$	22,338	$	71	$	—	$	22,409
Government-related debt securities	5,000		3		—		5,003
Asset-backed securities	1,462		9		—		1,471
Total available-for-sale debt securities	$	28,800	$	83	$	—	$	28,883

Fair Values of Available-for-Sale Securities by Contractual Maturity

The fair values of available-for-sale debt securities by contractual maturity were as follows (in thousands):

	September 30, 2021		December 31, 2020
Maturing in one year or less	$	185,131	$	28,883
Maturing in one to three years	77,556		—
Total available-for-sale debt securities	$	262,687	$	28,883

Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value

The following table summarizes investments that have been in a continuous unrealized loss position as of September 30, 2021 (in thousands).

	Less than 12 months				12 months or greater				Total
	Fair Value		Gross unrealized losses		Fair Value		Gross unrealized losses		Fair Value		Gross unrealized losses
Corporate debt securities	$	41,858	$	(22)	$	—	$	—	$	41,858	$	(22)
Government-related debt securities	33,174		(12)		—		—		33,174		(12)
Asset Backed Securities	11,202		(9)		—		—		11,202		(9)
Total	$	86,234	$	(43)	$	—	$	—	$	86,234	$	(43)