Note 3 - Financial Instruments - Summary of Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Financial Assets	$ 16,108	$ 68,830
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Financial Assets
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
Financial Assets
Cash and Cash Equivalents [Member]
Financial Assets	$ 16,108	$ 68,830
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Financial Assets	$ 57,429	$ 6,508
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Financial Assets
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Financial Assets
US Government Agencies Debt Securities [Member]
Financial Assets	$ 57,429	$ 6,508
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Financial Assets
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Financial Assets	$ 490	$ 8,247
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Financial Assets
Corporate Debt Securities [Member]
Financial Assets	$ 490	$ 8,247
Fair Value, Inputs, Level 1 [Member] | Foreign Currency Forward Contracts [Member]
Financial Liabilities
Fair Value, Inputs, Level 1 [Member]
Financial Assets	$ 73,537	75,338
Financial Liabilities
Fair Value, Inputs, Level 2 [Member] | Foreign Currency Forward Contracts [Member]
Financial Liabilities	$ 112
Fair Value, Inputs, Level 2 [Member]
Financial Assets	490	$ 8,247
Financial Liabilities	$ 112
Fair Value, Inputs, Level 3 [Member] | Foreign Currency Forward Contracts [Member]
Financial Liabilities
Fair Value, Inputs, Level 3 [Member]
Financial Assets
Financial Liabilities
Foreign Currency Forward Contracts [Member]
Financial Liabilities	$ 112
Financial Assets	74,027	$ 83,585
Financial Liabilities	$ 112