Financial Instruments

6 Months Ended

Jun. 30, 2021

Investments All Other Investments [Abstract]

4.	Financial Instruments

Cash equivalents and investments (debt securities) which are classified as available-for-sale securities, consisted of the following (in thousands):

June 30, 2021	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Money market funds (cash equivalents)	$	73,621	$	—	$	—	$	73,621
U.S. government agency securities		7,778		1		—		7,779
Federal agency securities		5,122		1		—		5,123
Total financial assets	$	86,521	$	2	$	—	$	86,523
Classified as:
Cash and cash equivalents							$	73,621
Short-term investments								12,902
Total financial assets							$	86,523

December 31, 2020	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Money market funds (cash equivalents)	$	30,360	$	—	$	—	$	30,360
U.S. government agency securities		37,835		2		—		37,837
Federal agency securities		13,697		3		—		13,700
Total financial assets	$	81,892	$	5	$	—	$	81,897
Classified as:
Cash and cash equivalents							$	30,360
Short-term investments								48,994
Long-term investments								2,543
Total financial assets							$	81,897

There have been no material realized gains or losses on available-for-sale debt securities for the periods presented. As of June 30, 2021, the remaining contractual maturities of $12.9 million of available-for-sale debt securities were less than one year.

The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable, and other accrued liabilities approximate their fair values due to the short-term maturity of these instruments.