Note 10 - Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2020

Notes Tables

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Fair Value Measurements Using
March 31, 2020	Fair Value		Quoted Prices in Active Markets For Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents	$	69,492	$	69,492	$	–	$	–
Restricted cash and cash equivalents		14,688		14,688		–		–
Marketable equity securities		92,061		92,061		–		–
Corporate debt securities		67,151		47,434		19,717		–
Mortgage–backed securities		53,465		–		53,465		–
U.S. Treasury securities		14,130		14,130		–		–
State and municipal securities		13,065		1,974		11,091		–
Total financial assets	$	324,052	$	239,779	$	84,273	$	–

	Fair Value Measurements Using
December 31, 2019	Fair Value		Quoted Prices in Active Markets For Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents	$	50,334	$	50,334	$	–	$	–
Restricted cash and cash equivalents		10,676		10,676		–		–
Marketable equity securities		152,453		152,453		–		–
Corporate debt securities		65,653		48,584		17,069		–
Asset - backed securities		55,185		–		55,185		–
U.S. Treasury securities		13,410		13,410		–		–
State and municipal securities		13,158		1,975		11,183		–
Total financial assets	$	360,869	$	277,432	$	83,437	$	–