Note 11 - Revenue Streams and Concentrations - Revenue Streams (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues		$ 15,591	$ 15,762	$ 15,658	$ 15,755	$ 16,200	$ 16,252	$ 16,890	$ 16,726	$ 62,766	$ 66,068	$ 68,526
Revenue Benchmark [Member]
Revenues, percentage										100.00%	100.00%
Month-to-Month Customers [Member]
Revenues, within scope of ASU 2014-09										$ 27,617	$ 29,556
Revenues, percentage within scope of ASU 2014-09										61.30%	61.30%
Month-to-Month Customers [Member] | Revenue, Product and Service Benchmark [Member]
Revenues, percentage										44.00%
Month-to-Month Customers [Member] | Revenue Benchmark [Member]
Revenues, percentage											44.70%
Competitive Local Exchange Carrier Business Customers [Member]
Revenues, within scope of ASU 2014-09										$ 13,162	$ 14,060
Revenues, percentage within scope of ASU 2014-09										29.20%	29.10%
Competitive Local Exchange Carrier Business Customers [Member] | Revenue, Product and Service Benchmark [Member]
Revenues, percentage										21.00%
Competitive Local Exchange Carrier Business Customers [Member] | Revenue Benchmark [Member]
Revenues, percentage											21.30%
Network Access Customers [member]
Revenues, within scope of ASU 2014-09										$ 2,513	$ 2,711
Revenues, percentage within scope of ASU 2014-09										5.60%	5.60%
Network Access Customers [member] | Revenue, Product and Service Benchmark [Member]
Revenues, percentage										4.00%
Network Access Customers [member] | Revenue Benchmark [Member]
Revenues, percentage											4.10%
Month-to-Month, Competitive Local Exchange Carrier Business, and Network Access Customers [Member]
Revenues, within scope of ASU 2014-09										$ 43,292	$ 46,327
Revenues, percentage within scope of ASU 2014-09										96.10%	96.00%
Month-to-Month, Competitive Local Exchange Carrier Business, and Network Access Customers [Member] | Revenue, Product and Service Benchmark [Member]
Revenues, percentage										69.00%
Month-to-Month, Competitive Local Exchange Carrier Business, and Network Access Customers [Member] | Revenue Benchmark [Member]
Revenues, percentage											70.10%
Global Access Customers [Member]
Revenues, within scope of ASU 2014-09	[1]									$ 1,770	$ 1,932
Revenues, percentage within scope of ASU 2014-09	[1]									3.90%	4.00%
Global Access Customers [Member] | Revenue, Product and Service Benchmark [Member]
Revenues, percentage	[1]									2.80%
Global Access Customers [Member] | Revenue Benchmark [Member]
Revenues, percentage	[1]										2.90%
Month-to-Month, Competitive Local Exchange Carrier Business, Network Access, and Global Access Customers [Member]
Revenues, within scope of ASU 2014-09										$ 45,062	$ 48,259
Revenues, percentage within scope of ASU 2014-09										100.00%	100.00%
Month-to-Month, Competitive Local Exchange Carrier Business, Network Access, and Global Access Customers [Member] | Revenue, Product and Service Benchmark [Member]
Revenues, percentage										71.80%
Month-to-Month, Competitive Local Exchange Carrier Business, Network Access, and Global Access Customers [Member] | Revenue Benchmark [Member]
Revenues, percentage											73.00%
Managed Services [Member]
Revenues	[2]									$ 626	$ 639
Managed Services [Member] | Revenue, Product and Service Benchmark [Member]
Revenues, percentage	[2]									1.00%
Managed Services [Member] | Revenue Benchmark [Member]
Revenues, percentage	[2]										1.00%
Sales Channel, Directly to Consumer [Member]
Revenues										$ 45,688	$ 48,898
Sales Channel, Directly to Consumer [Member] | Revenue, Product and Service Benchmark [Member]
Revenues, percentage										72.80%
Sales Channel, Directly to Consumer [Member] | Revenue Benchmark [Member]
Revenues, percentage											74.00%
Local services [Member]
Revenues										$ 19,313	$ 20,948
Local services [Member] | Sales Channel, Directly to Consumer [Member]
Revenues										19,313	20,948
Network Access [Member]
Revenues										21,210	21,662
Network Access [Member] | Sales Channel, Directly to Consumer [Member]
Revenues										4,283	4,643
Internet [Member]
Revenues										14,646	15,221
Internet [Member] | Sales Channel, Directly to Consumer [Member]
Revenues										14,646	15,221
Transport Services [Member]
Revenues										4,236	4,774
Transport Services [Member] | Sales Channel, Directly to Consumer [Member]
Revenues										4,085	4,623
Video and Security [Member]
Revenues										2,735	2,824
Video and Security [Member] | Sales Channel, Directly to Consumer [Member]
Revenues										2,735	2,824
Management Service [Member]
Revenues										626	639
Management Service [Member] | Sales Channel, Directly to Consumer [Member]
Revenues										626	639
Indefeasible Rights-Of-Use Agreements, Outside of ASU 2014-09 Scope [Member]
Revenues	[2]									$ 151	$ 151
Indefeasible Rights-Of-Use Agreements, Outside of ASU 2014-09 Scope [Member] | Revenue, Product and Service Benchmark [Member]
Revenues, percentage	[2]									0.20%
Indefeasible Rights-Of-Use Agreements, Outside of ASU 2014-09 Scope [Member] | Revenue Benchmark [Member]
Revenues, percentage	[2]										0.20%
Network Access, Outside of ASU 2014-09 Scope [Member]
Revenues	[2]									$ 16,927	$ 17,019
Network Access, Outside of ASU 2014-09 Scope [Member] | Revenue, Product and Service Benchmark [Member]
Revenues, percentage	[2]									27.00%
Network Access, Outside of ASU 2014-09 Scope [Member] | Revenue Benchmark [Member]
Revenues, percentage	[2]										25.80%

[1] Fixed fees charged to MTM customers and CLEC business customers.

[2] Revenue generated from sources not within the scope of ASU 2014-09. See Note 2, Summary of Significant Accounting Policies – Revenue Recognition, for accounting policies associated with these sources of revenue.