Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Marketable Securities
Amortized Cost	$ 2,250	$ 157,640
Gross Unrealized Gains	0	14
Gross Unrealized Losses	0	(5)
Fair Value	2,250	157,649
Treasury securities
Marketable Securities
Amortized Cost	0	10,038
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	(2)
Fair Value	0	10,036
Corporate debt securities
Marketable Securities
Amortized Cost	2,250	127,003
Gross Unrealized Gains	0	13
Gross Unrealized Losses	0	(3)
Fair Value	2,250	127,013
Agency securities
Marketable Securities
Amortized Cost	0	20,599
Gross Unrealized Gains	0	1
Gross Unrealized Losses	0	0
Fair Value	$ 0	$ 20,600

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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Amount, before tax, of unrealized loss 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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Amortized cost of 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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Amount of 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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