Note 4 - Revenue - Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue	$ 172,948	$ 163,097	$ 525,879	$ 466,926
Warrant contra revenue	(161)	(410)	(991)	(1,173)
Net revenue	172,787	162,687	524,888	465,753
Communications [Member]
Revenue	56,676	54,834	161,961	160,362
E-Commerce and Consumer [Member]
Revenue	22,434	23,320	74,757	71,884
Health Care and Education [Member]
Revenue	15,315	18,774	73,020	44,757
Media [Member]
Revenue	22,863	25,536	72,435	70,801
Financial and Business Service [Member]
Revenue	17,161	12,208	48,374	36,034
Travel and Hospitality [Member]
Revenue	12,027	15,063	33,066	45,028
Technology, IT and Related Service [Member]
Revenue	5,125	4,813	15,064	14,310
Other Sector [Member]
Revenue	$ 21,347	$ 8,549	$ 47,202	$ 23,750