Note 3 - Financial Instruments (Details) - Summary of Assets and Liabilities Measured at Fair Value (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Financial assets
Assets	$ 83,585	$ 5,140
Financial liabilities
Liabilities		1,443
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 3 [Member]
Financial liabilities
Liabilities		1,443
Derivative Financial Instruments, Liabilities [Member]
Financial liabilities
Liabilities		1,443
Fair Value, Inputs, Level 1 [Member] | Cash Equivalents [Member]
Financial assets
Assets	68,830	2,781
Fair Value, Inputs, Level 1 [Member] | US Government Agencies Debt Securities [Member]
Financial assets
Assets	6,508	2,359
Fair Value, Inputs, Level 1 [Member]
Financial assets
Assets	75,338	5,140
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Financial assets
Assets	8,247
Fair Value, Inputs, Level 2 [Member]
Financial assets
Assets	8,247
Fair Value, Inputs, Level 3 [Member]
Financial liabilities
Liabilities		1,443
Cash Equivalents [Member]
Financial assets
Assets	68,830	2,781
US Government Agencies Debt Securities [Member]
Financial assets
Assets	6,508	2,359
Corporate Debt Securities [Member]
Financial assets
Assets	$ 8,247