Marketable Securities and Fair Value Measurements - Schedule of Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair value measurements
Amortized Cost	$ 121,005	$ 82,824
Gross Unrealized Losses	(201)	(231)
Securities, available-for-sale	120,804	82,593
Investment securities
Fair value measurements
Amortized Cost	114,402	61,129
Gross Unrealized Losses	(124)	(97)
Securities, available-for-sale	114,278	61,032
Investment securities
Fair value measurements
Amortized Cost	6,603	21,695
Gross Unrealized Losses	(77)	(134)
Securities, available-for-sale	$ 6,526	$ 21,561

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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-Section 50
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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).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
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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).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
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