Note 10 - Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2019

Notes Tables

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

	Fair Value Measurements Using
September 30, 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	$	59,261	$	59,261	$	–	$	–
Restricted cash and cash equivalents		8,821		8,821		–		–
Marketable equity securities		156,319		156,319		–		–
Corporate debt securities		64,683		48,941		15,742		–
Mortgage–backed securities		58,454		–		58,454		–
U.S. Treasury securities		13,211		13,211		–		–
State and municipal securities		13,209		–		13,209		–
Total financial assets	$	373,958	$	286,553	$	87,405	$	–

	Fair Value Measurements Using
December 31, 2018	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	$	43,247	$	43,247	$	–	$	–
Restricted cash and cash equivalents		11,673		11,673		–		–
Marketable equity securities		140,223		140,223		–		–
Corporate debt securities		67,632		47,921		19,711		–
Asset - backed securities		62,068		–		62,068		–
U.S. Treasury securities		21,457		21,457		–		–
State and municipal securities		21,436		–		21,436		–
Total financial assets	$	367,736	$	264,521	$	103,215	$	–