Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Capitalized Contract Cost, Net, Total	$ 3,600
Capitalized Contract Cost, Accumulated Amortization	1,400
Contract with Customer, Asset, Net, Total	4,000		$ 3,900
Retained Earnings (Accumulated Deficit), Ending Balance	$ (40,460)		$ (43,459)
Accounting Standards Update 2014-09 [Member]
Retained Earnings (Accumulated Deficit), Ending Balance		$ 1,500

Amount of accumulated amortization of asset recognized from cost incurred to obtain or fulfill contract with customer.

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