Note 2 - Investment Securities (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

Cash, Cash Equivalents and Investments [Table Text Block]

	December 31,
	201 9		201 8
Cash and cash equivalents:
Cash	$	20,005	$	21,969
Cash equivalents:
Money market funds		6,311		4,083
Total cash and cash equivalents		26,316		26,052
Marketable securities:
U.S. government notes		4,114		1,397
U.S. government agencies		—		2,677
Municipal securities		—		200
Commercial paper		3,491		2,433
Corporate debt securities		—		2,816
Total marketable securities		7,605		9,523
Total cash, cash equivalents and marketable securities	$	33,921	$	35,575

Unrealized Gain (Loss) on Investments [Table Text Block]

December 31, 201 9	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Market Value
Cash and cash equivalents	$	26,316	$	-	$	-	$	26,316
Marketable investments
U.S. government notes		4,114		-		-		4,114
U.S. government agencies		—		-		-		—
Municipal securities		—		-		-		—
Commercial paper		3,491		-		-		3,491
Corporate debt securities		—		-		-		—
Total marketable securities		7,605		-		-		7,605
Total cash, cash equivalents and marketable securities	$	33,921	$	-	$	-	$	33,921

December 31, 2018	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Market Value
Cash and cash equivalents	$	26,052	$	-	$	-		$	26,052
Marketable investments
U.S. government notes		1,397		-		-			1,397
U.S. government agencies		2,677		-		-			2,677
Municipal securities		200		-		-			200
Commercial paper		2,433		-		-			2,433
Corporate debt securities		2,825		-		(9	)		2,816
Total marketable securities		9,532				(9	)		9,523
Total cash, cash equivalents and marketable securities	$	35,584			$	(9	)	$	35,575

Investments Classified by Contractual Maturity Date [Table Text Block]

	Amount
Due in less than one year	$	7,605
Due in 1 to 3 years		—
Total marketable securities	$	7,605

Fair Value Measurements, Recurring and Nonrecurring [Table Text Block]

December 31, 201 9	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	6,311	$	-	$	-	$	6,311
Short term marketable investments:
Available-for-sale securities		4,114		3,491		-		7,605
Total assets at fair value	$	10,425	$	3,491	$	-	$	13,916

December 31, 2018 *	Level 1		Level 2		Level 3		Total
Cash equivalents:
Money market funds	$	4,083	$	-	$	-	$	4,083
Short term marketable investments:
Available-for-sale securities		4,274		5,249		-		9,523
Total assets at fair value	$	8,357	$	5,249	$	-	$	13,606