Note 6 - Commitments and Contingent Liabilities (Details Textual) - USD ($) $ in Thousands		12 Months Ended
	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Leases, Rent Expense		$ 3,258	$ 4,296	$ 2,986
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals		1,509
Deferred Rent Credit, Current		624	514
Deferred Rent Credit, Noncurrent		$ 5,377	$ 5,366
Promissory Note [Member]
Line of Credit Facility, Maximum Borrowing Capacity	$ 7,000
Debt Instrument, Basis Spread on Variable Rate	0.15%
Line of Credit Facility, Interest Rate at Period End		3.60%
Long-term Line of Credit		$ 0