Note 5 - Accounts Receivable (Details Textual) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accounts Receivable, after Allowance for Credit Loss, Current, Total	$ 25,659	$ 31,472
Rural Health Care Customers [Member]
Accounts Receivable, after Allowance for Credit Loss, Current, Total	$ 5,198	$ 8,122

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant