Fair Value of Financial Assets and Liabilities - By Type (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Marketable securities:
Amortized Cost	$ 35,501	$ 39,074
Gross Unrealized Gain	28	7
Gross Unrealized Loss	(1)	(3)
Fair Value	35,528	39,078
Corporate debt securities
Marketable securities:
Amortized Cost	5,688	7,815
Gross Unrealized Gain	2	2
Fair Value	5,690	7,817
Commercial paper
Marketable securities:
Amortized Cost	15,768	15,129
Fair Value	15,768	15,129
Asset-backed securities
Marketable securities:
Amortized Cost	1,408	8,004
Gross Unrealized Gain		4
Gross Unrealized Loss	(1)
Fair Value	1,407	8,008
U.S. government agency debt securities
Marketable securities:
Amortized Cost	12,637	8,126
Gross Unrealized Gain	26	1
Gross Unrealized Loss		(3)
Fair Value	$ 12,663	$ 8,124

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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