Note 4 - Fair Value Measurements

12 Months Ended

Dec. 31, 2016

Notes to Financial Statements

Fair Value Disclosures [Text Block]

4.

Fair Value Measurements

The Company’s investments are all classified within Level

2

of the fair value hierarchy. The Company’s investments classified within Level

2

of the fair value hierarchy are valued based on matrix pricing compiled by

third

party pricing vendors, using observable market inputs such as interest rates, yield curves, and credit risk.

The fair value hierarchy of the Company’s cash equivalents and investments at fair value is as follows:

			Fair Value Measurements at Reporting Date Using
	December 31, 2016		Quoted Prices in Active Markets  for Identical Assets   (Level 1)		Significant Other  Observable Inputs   (Level 2)		Significant   Unobservable Inputs   (Level 3)
Cash equivalents:
Money market funds	$	68,352	$	-	$	68,352	$	-
Bank certificates of deposit		750		-		750		-
Total cash equivalents		69,102		-		69,102		-
Investments:
Bank certificates of deposit	$	20,500	$	-	$	20,500	$	-

			Fair Value Measurements at Reporting Date Using
	December 31, 2015		Quoted Prices in Active Markets  for Identical Assets  (Level 1)		Significant Other  Observable Inputs  (Level 2)		Significant   Unobservable Inputs  (Level 3)
Cash equivalents:
Money market funds	$	61,385	$	-	$	61,385	$	-
Bank certificates of deposit		250		-		250		-
Total cash equivalents	$	61,635	$	-	$	61,635	$	-
Investments:
Corporate debt securities	$	2,001	$	-	$	2,001	$	-
Bank certificates of deposit		25,750		-		25,750		-
Total investments	$	27,751	$	-	$	27,751	$	-

The Company did not have any transfers between Level

1

and Level

2

or transfers in or out of Level

3

of the fair value hierarchy during the years ended

December

31,

2016

and

2015.