Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Summary of Placement in the Fair Value Hierarchy of Financial Assets that are Measured at Fair Value on a Recurring Basis

The following table presents the placement in the fair value hierarchy of financial assets that are measured at fair value on a recurring basis, including the items for which the fair value option has been elected, as of December 31, 2019:

	Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		December 31, 2019
Assets
United States government debt securities	$	—	$	8,996	$	—	$	8,996
Other	—		264		—		264
Total	$	—	$	9,260	$	—	$	9,260

The following table presents the placement in the fair value hierarchy of financial assets that are measured at fair value on a recurring basis, including the items for which the fair value option has been elected, as of December 31, 2018:

	Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		December 31, 2018
Assets
United States government debt securities	$	—	$	119,340	$	—	$	119,340
Equity securities	950		74		—		1,024
Other	—		394		191		585
Total	$	950	$	119,808	$	191	$	120,949

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation

The following table summarizes the changes in the Level 3 investments during the years ended December 31, 2019 and 2018.

	2019			2018
Beginning balance	$	191		$	161,225
Retained interest in deconsolidated subsidiary	14,239			—
Dividend income from investments in preferred stock	48			14,841
Net unrealized appreciation (depreciation) in the fair value of the investments in equity securities and preferred stock	7,446			(17,499		)
Return of preferred stock	—			(158,376		)
Proceeds from sale of equity securities	(21,587		)	—
Proceeds to be received from preferred stock	(337		)	—
Ending balance	$	—		$	191