Note 4 - Property and Equipment, Net - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Property and equipment and finance lease	$ 209,195	$ 183,893
Less: accumulated depreciation and amortization	(141,621)	(123,314)
Property and equipment and finance lease, net	67,574	60,579
Computer Equipment [Member]
Property and equipment and finance lease	133,628	112,599
Computer Software, Intangible Asset [Member]
Property and equipment and finance lease	26,298	26,137
Furniture and Fixtures [Member]
Property and equipment and finance lease	8,335	6,973
Assets Held under Capital Leases [Member]
Property and equipment and finance lease	3,503	3,503
Scanner Appliances [Member]
Property and equipment and finance lease	16,388	15,864
Leasehold Improvements [Member]
Property and equipment and finance lease	$ 21,043	$ 18,817