Note 4 - Investments

6 Months Ended

Jun. 30, 2017

Notes to Financial Statements

Cash and Cash Equivalents Disclosure [Text Block]

4.

       Investments

All of the Company’s investments are classified as available-for-sale and are carried at fair value with unrealized gains and losses recorded as a component of accumulated other comprehensive income, net of related income taxes. The Company held bank certificates of deposit of

$25.0

million and

$20.5

million at

June 30, 2017

and

December 31, 2016,

respectively. There were

no

unrealized gains or losses on the Company’s available-for-sale securities at

June 30, 2017

or

December 31, 2016.