Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2019

Investments Debt And Equity Securities [Abstract]

Summary of Major Security Type Assets Measured at Fair Value on Recurring Basis

The following table summarizes, by major security type, our assets that are measured at fair value on a recurring basis (in thousands):

	September 30, 2019
	Amortized		Gross Unrealized		Gross Unrealized		Estimated Fair
	Cost		Gains		Losses		Value
Corporate debt securities	$	4,996	$	10	$	—	$	5,006
Government treasury bills		—		—		—		—
	$	4,996	$	10	$	—	$	5,006

	December 31, 2018
	Amortized		Gross Unrealized		Gross Unrealized			Estimated Fair
	Cost		Gains		Losses			Value
Corporate debt securities	$	31,977	$	3	$	(7	)	$	31,973
Government treasury bills		26,662		—		(5	)		26,657
	$	58,639	$	3	$	(12	)	$	58,630

Schedule of Estimated Fair Value of Investments by Contractual Maturity

The estimated fair value of investments by contractual maturity is as follows (in thousands):

	September 30,		December 31,
	2019		2018
Due within one year	$	5,006	$	58,630
Total	$	5,006	$	58,630