Note 14 - Employee Benefit Plan

12 Months Ended

Dec. 31, 2018

Notes to Financial Statements

Compensation and Employee Benefit Plans [Text Block]

14.

Employee Benefit Plan

The Company’s U.S. employees are eligible to participate in the Company’s

401

(k) savings plan. Employees

may

elect to contribute a percentage of their compensation to the plan, and the Company will make

140%

matching contributions up to a limit of

5%

of an employee’s eligible compensation. In addition, the Company

may

make annual discretionary contributions. The Company made matching contributions of

$0.8

million,

$0.6

million, and

$0.6

million for the years ended

December 

31,

2018,

2017,

and

2016,

respectively.