Note 6 - Deferred Revenue (Tables)

3 Months Ended

Mar. 31, 2020

Notes Tables

Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block]

	Three Months Ended
	March 31,
	2020			2019
Beginning Balance	$	14,222	$	12,566
Add: Payments received		2,058		3,173
Less: Revenue		(3,312)		(2,649)
Ending Balance	$	12,969	$	13,090