Note 4 - Fair Value Measurements - Liabilities Measured on a Recurring Basis (Details) - Fair Value, Measurements, Recurring [Member] $ in Thousands	Dec. 31, 2017 USD ($)
Contingent consideration liability	$ 5,744
Fair Value, Inputs, Level 1 [Member]
Contingent consideration liability
Fair Value, Inputs, Level 2 [Member]
Contingent consideration liability
Fair Value, Inputs, Level 3 [Member]
Contingent consideration liability	$ 5,744