Financial Instruments

6 Months Ended

Jun. 30, 2022

Investments, Debt and Equity Securities [Abstract]

Cash equivalents and marketable securities are recorded at fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. To increase the comparability of fair value measures, the following hierarchy prioritizes the inputs to valuation methodologies used to measure fair value.

•Level 1—Valuations based on quoted prices in active markets for identical assets or liabilities.

•Level 2—Valuations based on quoted prices for similar assets and liabilities in active markets or inputs that are observable for the assets or liabilities, either directly or indirectly through market corroboration.

•Level 3—Valuations based on unobservable inputs reflecting our own assumptions used to measure assets and liabilities at fair value. These valuations require significant judgment.

The following table summarizes, by major security type, our restricted cash, cash equivalents, and marketable securities that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy (in thousands):


	June 30, 2022								December 31, 2021
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value		Fair Value
Level 1:
Restricted cash:
Restricted cash	$	10,755	$	—	$	—	$	10,755	$	10,823
Total restricted cash	$	10,755	$	—	$	—	$	10,755	$	10,823

Level 1 securities:
Cash equivalents:
Money market funds	$	166,174	$	—	$	—	$	166,174	$	73,138


Total cash equivalents	$	166,174	$	—	$	—	$	166,174	$	73,138

Level 2 securities:
Marketable securities:
Commercial paper	$	127,113	$	—	$	—	$	127,113	$	59,792
Asset-backed securities	28,317		—		(90)		28,227		40,942
Corporate bonds	208,362		—		(3,465)		204,897		237,402
U.S. treasury securities	181,344		—		(2,164)		179,180		272,300
Supranational bonds	53,027		—		(969)		52,058		70,887

Total marketable securities	$	598,163	$	—	$	(6,688)	$	591,475	$	681,323

We do not intend to sell any of the securities in an unrealized loss position and we expect to realize the full value of all these investments, which may be upon maturity. We did not recognize any credit losses related to our available-for-sale debt securities during the three and six months ended June 30, 2022 and 2021.

The following table summarizes the amortized cost and fair value of our marketable securities as of June 30, 2022, by contractual years to maturity (in thousands):


	Amortized Cost		Fair Value
Due within one year	$	542,211	$	537,242
Due between one and two years	55,952		54,233
Total	$	598,163	$	591,475

There were no material realized or unrealized gains or losses, either individually or in the aggregate, during the three and six months ended June 30, 2022 and 2021.

Nonrecurring Fair Value Measurements

We hold equity investments in certain unconsolidated entities without a readily determinable fair value. These strategic investments represent less than a 20% ownership interest in each of the entities, and we do not have significant influence over or control of the entities. We elected the practical expedient in Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") Topic 321, Investments-Equity Securities, and measure these investments at cost less any impairment, adjusted for observable price changes, if any. As of June 30, 2022, the equity investments totaled $15.6 million.