Note 2 - Revenue Recognition - Disaggregation of Revenue by Type (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Revenues	$ 96,204	$ 79,988
Revenues, percentage	100.00%	100.00%
Revenues, variance	$ 16,216
Revenues, variance, percentage	20.30%
Internet [Member]
Revenues	$ 81,511	$ 67,023
Revenues, percentage	84.70%	83.80%
Revenues, variance	$ 14,488
Revenues, variance, percentage	21.60%
Contact Center [Member]
Revenues	$ 14,693	$ 12,965
Revenues, percentage	15.30%	16.20%
Revenues, variance	$ 1,728
Revenues, variance, percentage	13.30%
Reorder Customer [Member]
Revenues	$ 80,425	$ 67,742
Revenues, percentage	83.60%	84.70%
Revenues, variance	$ 12,683
Revenues, variance, percentage	18.70%
New Order Customer [Member]
Revenues	$ 15,779	$ 12,246
Revenues, percentage	16.40%	15.30%
Revenues, variance	$ 3,533
Revenues, variance, percentage	28.90%