Note 3 - Contracts With Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue	$ 133,277	$ 127,982	$ 119,686
Transferred over Time [Member] | Subscription Services [Member]
Revenue	122,499	114,216	104,777
Transferred over Time [Member] | Fixed, Non-subscription Services [Member]
Revenue	2,907	3,248	3,163
Transferred over Time [Member] | Unit Price Services [Member]
Revenue	4,939	5,526	6,971
Transferred at Point in Time [Member] | Service [Member]
Revenue	$ 2,932	$ 4,992	$ 4,775