Note 18 - Segment Reporting - Information by Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Net Revenues	$ 85,612	$ 83,519	$ 81,087	$ 95,795	$ 90,621	$ 85,008	$ 84,223	$ 69,568	$ 346,013	$ 329,421	[1]	$ 189,819	[1]
Cost of revenues									232,103	230,600	[1]	120,187	[1]
Network expenses									9,846	9,324	[1]	5,210	[1]
Depreciation of property and equipment									5,298	3,142	[1]	1,320	[1]
Amortization of intangible assets									1,996	1,834	[1]	48	[1]
Total cost of revenues									249,243	244,900	[1]	126,765	[1]
Gross Profit	$ 27,731	$ 24,262	$ 22,158	$ 22,619	$ 25,736	$ 20,494	$ 21,347	$ 16,944	96,770	84,521	[1]	63,054	[1]
Sales and marketing									33,063	29,423	[1]	20,755	[1]
Technical operations and development									8,748	7,258	[1]	4,495	[1]
General and administrative									17,710	13,594	[1]	11,405	[1]
Depreciation of property and equipment									424	585	[1]	504	[1]
Amortization of intangible assets									7,247	6,566	[1]	905	[1]
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)										111	[2]	43	[2]
Loss (gain) on currency forward contracts									254	(98)	[1]	(99)	[1]
Income from operations									29,324	27,082	[1]	25,047	[1]
Other income (expenses), net									(3,169)	(3,007)	[1]	66	[1]
Income before provision for income taxes									26,155	24,075	[1]	25,113	[1]
Network Access Services [Member]
Net Revenues									97,324	89,452		74,306
Cost of revenues									50,055	48,640		37,825
Network expenses									2,029	1,861		1,399
Depreciation of property and equipment									4,063	2,201		977
Amortization of intangible assets									46	46		48
Total cost of revenues									56,193	52,748		40,249
Gross Profit									41,131	36,704		34,057
Domain Name Services [Member]
Net Revenues									248,689	239,969		115,513
Cost of revenues									182,048	181,960		82,362
Network expenses									7,817	7,463		3,811
Depreciation of property and equipment									1,235	941		343
Amortization of intangible assets									1,950	1,788
Total cost of revenues									193,050	192,152		86,516
Gross Profit									$ 55,639	$ 47,817		$ 28,997

[1] The Company has initially applied ASC 2014-09 (Topic 606) using the modified retrospective method. Under this method, the comparative information is not restated.

[2] The Company has initially applied ASC 2014-09 (Topic 606) using the modified retrospective method. Under this method, the comparative information is not restated.