Cash Equivalents and Marketable Securities

12 Months Ended

Dec. 31, 2019

Investments Debt And Equity Securities [Abstract]

Cash Equivalents and Marketable Securities

4.  Cash Equivalents and Marketable Securities

The following tables summarize the estimated fair value of the Company’s cash equivalents and marketable securities and the gross unrealized gains and losses (in thousands):

	December 31, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Cash equivalents:
Money market funds	$	7,023	$	—	$	—		$	7,023
Reverse repurchase agreements		6,250		—		—			6,250
Commercial paper		2,247		—		—			2,247
Total cash equivalents		15,520		—		—			15,520
Marketable securities:
Commercial paper		12,931		15		—			12,946
Corporate bonds		39,714		45		(9	)		39,750
Total marketable securities	$	52,645	$	60	$	(9	)	$	52,696

	December 31, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
Cash equivalents:
Money market funds	$	7,180	$	—	$	—		$	7,180
Reverse repurchase agreements		6,250		—		—			6,250
Commercial paper		5,977		—		(1	)		5,976
Total cash equivalents		19,407		—		(1	)		19,406
Marketable securities:
Commercial paper		47,964		—		(24	)		47,940
U.S. government securities		4,114		—		(2	)		4,112
Total marketable securities	$	52,078	$	—	$	(26	)	$	52,052

The reverse repurchase agreements are settled in cash nightly, and as such are classified as cash equivalents.

As of December 31, 2019 and 2018, all debt securities with an unrealized loss position have been in a loss position for less than one year. The aggregate fair value of debt securities in an unrealized loss position as of December 31, 2019 and 2018 were $13.0 million and $45.6 million, respectively, with no individual securities in a significant unrealized loss position. The Company evaluated its securities for other-than-temporary impairment and considered the decline in market value for the securities to be primarily attributable to current economic and market conditions and would not be required to sell the securities before recovery of the amortized cost basis. Based on this analysis, these marketable securities were not considered to be other-than-temporarily impaired as of December 31, 2019 and 2018.

The following table summarizes the contractual maturities of the Company's marketable securities at estimated fair value (in thousands):

	December 31,
	2019		2018
Due in one year or less	$	49,687	$	52,052
Due in 1 - 2 years		3,009		—
Total marketable securities	$	52,696	$	52,052

The Company may sell investments at any time for use in current operations even if they have not yet reached maturity. As a result, the Company classifies marketable securities, including securities with maturities beyond twelve months as current assets.