Investment Securities and Fair Value Measurements - Schedule of Available-for-sale Securities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Total available-for-sale investment securities	$ 14,451	$ 34,920
Gross Unrealized Gains	177	47
Gross Unrealized Losses	0	(2)
Estimated Fair Value	$ 14,628	$ 34,965
Maximum contractual maturity period	36 months	36 months
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Total available-for-sale investment securities	$ 1,597	$ 9,597
Gross Unrealized Gains	2	18
Gross Unrealized Losses	0	(1)
Estimated Fair Value	1,599	9,614
Agency securities
Debt Securities, Available-for-sale [Line Items]
Total available-for-sale investment securities	2,649	11,101
Gross Unrealized Gains	40	17
Gross Unrealized Losses	0	0
Estimated Fair Value	2,689	11,118
Treasury securities
Debt Securities, Available-for-sale [Line Items]
Total available-for-sale investment securities	10,205	14,222
Gross Unrealized Gains	135	12
Gross Unrealized Losses	0	(1)
Estimated Fair Value	$ 10,340	$ 14,233

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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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