XML 137 R121.htm IDEA: XBRL DOCUMENT v3.19.1
Note 15 - Stock-based Compensation (Details) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Remaining shares of common stock available for grant 302,066    
Expected life 10 years    
Minimum      
Vesting period 3 years    
Maximum      
Vesting period 7 years    
The 2008 Equity Incentive Plan [Member]      
Shares of common stock authorized 250,000    
2010 Equity Incentive Plan [Member]      
Shares of common stock authorized 350,000    
The 2013 Equity Incentive Plan [Member]      
Shares of common stock authorized 350,000    
The 2016 Equity Incentive Plan [Member]      
Shares of common stock authorized 400,000    
Employee Stock Purchase Plan      
Remaining shares of common stock available for grant 175,507    
Maximum amount any one participant can elect in an offering period $ 10,000    
Maximum amount any one particpant can contribute (as a percent) 10.00% 8.00% 8.00%