XML 26 R15.htm IDEA: XBRL DOCUMENT v3.7.0.1
Note 4 - Fair Value Measurements (Tables)
6 Months Ended
Jun. 30, 2017
Notes Tables  
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
           
Fair Value Measurements at Reporting Date Using
 
 
 
 
 
 
 
Quoted Prices in
 
 
Significant
 
 
 
 
 
 
 
 
 
 
 
Active Markets
 
 
Other
 
 
Significant
 
 
 
Balance at
 
 
for Identical
 
 
Observable
 
 
Unobservable
 
 
 
June 30,
 
 
Assets
 
 
Inputs
 
 
Inputs
 
 
 
201
7
 
 
(Level 1)
 
 
(Level 2)
 
 
(Level 3)
 
Money market funds
  $
21,790
    $
21,790
    $
    $
 
United States government and agency
   
19,981
     
4,997
     
14,984
     
 
United States corporate debt securities
   
12,590
     
     
12,590
     
 
United States commercial paper
   
25,450
     
     
25,450
     
 
Foreign commercial paper
   
25,960
     
     
25,960
     
 
Total
  $
105,771
    $
26,787
    $
78,984
    $
 
           
Fair Value Measurements at Reporting Date Using
 
 
 
 
 
 
 
Quoted Prices in
 
 
Significant
 
 
 
 
 
 
 
 
 
 
 
Active Markets
 
 
Other
 
 
Significant
 
 
 
Balance at
 
 
for Identical
 
 
Observable
 
 
Unobservable
 
 
 
December 31,
 
 
Assets
 
 
Inputs
 
 
Inputs
 
 
 
201
6
 
 
(Level 1)
 
 
(Level 2)
 
 
(Level 3)
 
Money market funds
  $
11,493
    $
11,493
    $
    $
 
United States corporate debt securities
   
12,039
     
     
12,039
     
 
Foreign corporate debt securities
   
14,057
     
     
14,057
     
 
United States commercial paper
   
8,635
     
     
8,635
     
 
Foreign commercial paper
   
2,993
     
     
2,993
     
 
Total
  $
49,217
    $
11,493
    $
37,724
    $