Investment in marketable securities (Tables)

3 Months Ended

Mar. 31, 2020

Investment in marketable securities

Schedule of fair value, amortized cost and unrealized holding gains and losses of marketable securities

	March 31, 2020
	Amortized		Unrealized		Unrealized
	Cost		gains		losses		Fair Value
	(unaudited)
U.S. treasury bonds	$	75,509	$	175	$	—	$	75,684
Corporate bonds		34,768		—		(119)		34,649
Total	$	110,277	$	175	$	(119)	$	110,333

	December 31, 2019
	Amortized		Unrealized		Unrealized
	Cost		gains		losses		Fair Value
U.S. treasury bonds	$	75,340	$	76	$	—	$	75,416
Corporate bonds		34,965		—		(17)		34,948
Total	$	110,305	$	76	$	(17)	$	110,364

Schedule of fair value and amortized cost of the available-for-sale securities by contractual maturity

	Amortized
	Cost		Fair Value
Due within one year	$	96,225	$	96,337
Due after one year through two years		14,052		13,996
Total	$	110,277	$	110,333