Note 3 - Contracts With Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue	$ 32,465	$ 30,013	$ 95,359	$ 89,047
Transferred over Time [Member] | Subscription Services [Member]
Revenue	28,629	26,328	84,460	77,746
Transferred over Time [Member] | Fixed, Non-subscription Services [Member]
Revenue	1,043	973	2,083	2,561
Transferred over Time [Member] | Unit Price Services [Member]
Revenue	1,187	1,905	4,585	5,817
Transferred at Point in Time [Member] | Subscription Services [Member]
Revenue	$ 1,606	$ 807	$ 4,231	$ 2,923