Short-term Investments

3 Months Ended

Mar. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Our investments consist of highly-rated instruments that mature in less than 12 months. We classify our short-term investments as available for sale. Available-for-sale securities are recorded on our condensed consolidated balance sheets at fair market value and any unrealized gains or losses are reported as part of other comprehensive loss on our condensed consolidated statements of comprehensive loss. We determine realized gains or losses on the sales of investments through the specific identification method and record such gains or losses as part of interest and other expense, net on our condensed consolidated statements of operations. We did not have any material realized gains or losses on investments during the three months ended March 31, 2021 and 2020. We measure the fair value of investments on a recurring basis.

Accrued interest receivables related to our available-for-sale securities of $0.6 million and $0.5 million as of March 31, 2021 and December 31, 2020 were included within prepaid expenses and other assets on our condensed consolidated balance sheets.

The following table summarizes, by major security type, our cash equivalents and short-term investments that are measured at fair value on a recurring basis (in thousands) as of March 31, 2021:


	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value		Cash equivalents		Short-term Investments
	(unaudited)
Money market funds	$	125,378	$	—	$	—	$	125,378	$	125,378	$	—
U.S. Treasury notes	49,123		7		—		49,130		—		49,130
Commercial paper	57,067		—		—		57,067		—		57,067
Corporate bonds	27,615		—		(5)		27,610		—		27,610

Total	$	259,183	$	7	$	(5)	$	259,185	$	125,378	$	133,807

The following table summarizes, by major security type, our cash equivalents and short-term investments that are measured at fair value on a recurring basis (in thousands) as of December 31, 2020:


	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value		Cash equivalents		Short-term Investments
Money market funds	$	79,387	$	—	$	—	$	79,387	$	79,387	$	—
US treasury notes	59,382		7		—		59,389		—		59,389
Commercial paper	68,018		—		—		68,018		—		68,018
Corporate bonds	48,494		8		(1)		48,501		—		48,501
Asset-backed securities	3,009		—		—		3,009		—		3,009
Total	$	258,290	$	15	$	(1)	$	258,304	$	79,387	$	178,917

On a quarterly basis we evaluate unrealized losses on our available-for-sale debt securities and the related accrued interest receivables to determine whether a decline in the fair value below the amortized cost basis is due to credit-related factors or noncredit-related factors. We do not intend to sell investments that are in an unrealized loss position and it is not likely that we will be required to sell any investments before recovery of their amortized cost basis. As of March 31, 2021 and December 31, 2020, there were no material unrealized losses due to credit-related factors.