Note 3 - Summary of Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member]
Financial Assets	$ 22,873	$ 39,233
Fair Value, Inputs, Level 1 [Member] | US Government Agencies Debt Securities [Member]
Financial Assets	$ 35,326	$ 25,232
Fair Value, Inputs, Level 1 [Member] | Foreign Currency Forward Contracts [Member]
Financial Liabilities
Fair Value, Inputs, Level 1 [Member]
Financial Assets	$ 58,199	$ 64,465
Financial Liabilities
Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member]
Financial Assets
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member]
Financial Assets
Fair Value, Inputs, Level 2 [Member] | Foreign Currency Forward Contracts [Member]
Financial Liabilities	$ 319	$ 537
Fair Value, Inputs, Level 2 [Member]
Financial Assets
Financial Liabilities	$ 319	$ 537
Fair Value, Inputs, Level 3 [Member] | Cash and Cash Equivalents [Member]
Financial Assets
Fair Value, Inputs, Level 3 [Member] | US Government Agencies Debt Securities [Member]
Financial Assets
Fair Value, Inputs, Level 3 [Member] | Foreign Currency Forward Contracts [Member]
Financial Liabilities
Fair Value, Inputs, Level 3 [Member]
Financial Assets
Financial Liabilities
Cash and Cash Equivalents [Member]
Financial Assets	$ 22,873	$ 39,233
US Government Agencies Debt Securities [Member]
Financial Assets	35,326	25,232
Foreign Currency Forward Contracts [Member]
Financial Liabilities	319	537
Financial Assets	58,199	64,465
Financial Liabilities	$ 319	$ 537