Note 9 - Income Taxes (Tables)
12 Months Ended
Dec. 31, 2014
Income Tax Disclosure [Abstract]  
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]
   

Year Ended December 31,

 
   

2014

   

2013

   

2012

 

United States

  $ (2,684 )   $ (2,507 )   $ (2,852 )

Foreign

    (18,186 )     (8,919 )     (4,166 )

Total

  $ (20,870 )   $ (11,426 )   $ (7,018 )
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]
   

Year Ended December 31,

 
   

2014

   

2013

   

2012

 

Current:

                       

U.S. Federal

  $ 350     $ 1,816     $ 3,760  

U.S. State

    55       1       (132 )

Foreign

    846       98       91  
      1,251       1,915       3,719  
                         

Deferred:

                       

U.S. Federal

    895       (135 )     4,842  

U.S. State

                5,088  

Foreign

    (408 )     (28 )     24  
      487       (163 )     9,954  

Total

  $ 1,738     $ 1,752     $ 13,673  
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
   

Year Ended December 31,

 
   

2014

   

2013

   

2012

 

Provision (benefit) at statutory rate

  $ (7,096 )   $ (3,886 )   $ (2,456 )

State income taxes

    1,651       303       200  

Research and development credits

    (7,384 )     (5,850 )     (1,345 )

Change in valuation allowance

    5,271       6,781       15,247  

Foreign earnings, taxed at different rates

    6,381       2,888       1,649  

Unrecognized tax benefits

    1,713       1,708       1,487  

Stock-based compensation

    166       142       336  

Tax exempt income

    (83 )     (157 )     (197 )

Prior year return to provision adjustment

    292       (257 )     (1,264 )

Cortina acquisition transaction cost

    444              

Other

    383       80       16  
    $ 1,738     $ 1,752     $ 13,673  
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]
   

December 31,

 
   

2014

   

2013

 

Deferred tax assets

               

Net operating loss carry forwards

  $ 8,314     $ 8,532  

Research and development credits

    30,637       15,460  

Stock-based compensation

    6,966       5,192  

Accrued expenses and allowances

    2,117       1,592  

Amortization and depreciation

    1,052        

Other temporary differences

    3,461       111  

Valuation allowance

    (39,682 )     (22,448 )

Total deferred tax assets

    12,865       8,439  
                 

Deferred tax liabilities

               

Subpart F income on foreign subsidiaries earnings

    (5,981 )     (5,621 )

Acquired intangible assets

    (6,157 )      

Amortization and depreciation

          (2,790 )

Other deferred tax liabilities

    (820 )      

Total deferred tax liabilities

    (12,958 )     (8,411 )

Deferred tax assets (liabilities), net

  $ (93 )   $ 28  
Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]
   

Year Ended December 31,

 
   

2014

   

2013

   

2012

 

Balance as of January 1

  $ 8,031     $ 6,155     $ 4,132  

Increases based on tax positions related to the current year

    3,102       1,918       1,418  

Increase (decreases) based on tax positions of prior year

    (61 )     (42 )     605  

Gross increases for acquired unrecognized tax benefits

    33,935              

Statute of limitation expirations

    (926 )            

Balance as of December 31

  $ 44,081     $ 8,031     $ 6,155