Marketable Securities - Schedule of Marketable Securities by Category (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 189,309	$ 62,681
Gross Unrealized Holding Gains	260	43
Gross Unrealized Holding Losses	6	40
Fair Value	189,563	62,684
Municipal notes and bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	80,926	62,681
Gross Unrealized Holding Gains	188	43
Gross Unrealized Holding Losses	6	40
Fair Value	81,108	$ 62,684
Asset-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,767
Gross Unrealized Holding Gains	12
Gross Unrealized Holding Losses	0
Fair Value	10,779
Certificates of deposits [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	30,500
Gross Unrealized Holding Gains	7
Gross Unrealized Holding Losses	0
Fair Value	30,507
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	30,707
Gross Unrealized Holding Gains	1
Gross Unrealized Holding Losses	0
Fair Value	30,708
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	36,409
Gross Unrealized Holding Gains	52
Gross Unrealized Holding Losses	0
Fair Value	$ 36,461

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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