Investments

3 Months Ended

Mar. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Our investments are classified as available-for-sale and consist of the following:


	March 31, 2021
	Amortized		Unrealized Gross				Aggregate
	Cost		Gains		Losses		Fair Value

Commercial paper	$	13,286	$	—	$	—	$	13,286
Corporate bonds	6,509		—		(3)		6,506

U.S. government securities	23,992		12		—		24,004
Short-term investments	$	43,787	$	12	$	(3)	$	43,796


	December 31, 2020
	Amortized		Unrealized Gross				Aggregate
	Cost		Gains		Losses		Fair Value

Commercial paper	$	13,275	$	—	$	—	$	13,275
Corporate bonds	6,543		—		(3)		6,540

U.S. government securities	23,997		32		—		24,029
Short-term investments	$	43,815	$	32	$	(3)	$	43,844

As of March 31, 2021 and December 31, 2020, we had no investments with a contractual maturity of greater than one year. Currently, we do not intend to sell the investments and it is not more likely than not that we will be required to sell the investments before recovery of their amortized cost bases, which may be maturity. We do not consider those investments to be other-than-temporarily impaired as of March 31, 2021. At the end of each reporting period,

we evaluate potential credit impairment on available-for-sale securities in an unrealized loss position, based on the expected cash flows to be collected and the yield-to-maturity on those securities. Securities with a valuation allowance for expected credit losses and deemed uncollectible are permanently written-down, and a reversal out of the valuation allowance occurs.