Note 5 - Fair Value Measurements

9 Months Ended

Sep. 30, 2019

Notes to Financial Statements

Fair Value Disclosures [Text Block]

5. Fair Value Measurements

The Company’s investments are all classified within Level

1

of the fair value hierarchy and are valued based on quoted prices in active markets. For cash and cash equivalents, current receivables, accounts payable, and interest accrual, the carrying amounts approximate fair value because of the short maturity of these instruments, and therefore fair value information is

not

included in the table below. The accretion to amortized cost included within interest and other income, net represented

$1.1

million and

$0.4

million as of

September 30, 2019

and

December 31, 2018.

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

			Fair Value Measurements at Reporting Date Using
			Quoted Prices in
			Active Markets		Significant Other		Significant
			for Identical Assets		Observable Inputs		Unobservable Inputs
	September 30, 2019		(Level 1)		(Level 2)		(Level 3)		Amortized Cost
Cash equivalents:
Money market funds	$	6,406	$	6,406	$	-	$	-	$	6,406
Investments:
U.S. treasury bills	$	69,825	$	69,825	$	-	$	-	$	69,821

			Fair Value Measurements at Reporting Date Using
			Quoted Prices in
			Active Markets		Significant Other		Significant
			for Identical Assets		Observable Inputs		Unobservable Inputs
	December 31, 2018		(Level 1)		(Level 2)		(Level 3)		Amortized Cost
Cash equivalents:
Money market funds	$	4,984	$	4,984	$	-	$	-	$	4,984
Investments:
U.S. treasury bills	$	69,972	$	69,972	$	-	$	-	$	69,972